Vines for the prairies

Sask Perennial Society
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Vines for the prairies

Jackie Bantle

Saskatchewan Perennial Society

Vines can be used to beautify a vertical garden structure, provide privacy, take advantage of vertical space when horizontal space is limited or cover a large space with one plant. Every situation is unique and sometimes it may seem that we lack vine options in our climate however, there are alternatives available.

One of the most common perennial vines found in the prairie landscape is the Virginia creeper (Parthenocissus quinquefolia). This hardy vine will cover a fence or horizontal structure in several years from planting. The leaves are palmately compound with five leaflets. Although the flowers and tiny fruit are insignificant, when grown in a sunny location, the red foliage color in the fall can be spectacular.

‘Dropmore Scarlet Honeysuckle’ is a fine textured vine, compared to the Virginia creeper. The roundish blue-green leaves provide a beautiful backdrop for the prolific and beautiful scarlet colored, trumpet shaped flowers that bloom from early to mid-summer. The flowers attract hummingbirds and the small red berries that ensue are a favorite food for birds. 

There are many types of clematis vines available for growing in the garden. Always check the hardiness zone when purchasing a clematis to survive the Prairie climate. Clematis need a structure to grow vertically since their vine twists around the structure as it grows. ‘Jackmanii’ is a vigorous growing clematis with profuse, dark purple flowers that bloom during the summer. ‘Jackmanii’ is recommended for zone 4: protect the roots in our climate with extra mulch in the fall. ‘Nelly Moser’ is another clematis recommended for zone 4 however, its flowers are bright pink and the bloom time is early summer.

‘Prairie Traveler’s Joy’ is a hardy clematis developed by Dr. Frank Skinner out of Manitoba. This clematis is not like the large flowering clematis previously mentioned however it is drought tolerant and will fill in a horizontal space where other plants may find it difficult to grow. The starry white flowers are only 2cm across and bloom later in the summer however, the clusters of flowers provide an attractive display at this time of the year. Considered invasive in some parts of the United States, be prepared to keep this plant in check.  ‘Rosy O’Grady’ clematis was also released by Dr. Skinner. Recommended for zone 3, ‘Rosy O’Grady’ has pink, bell-shaped flowers which appear in late spring followed by attractive seed heads in summer.  ‘Joe Zary’ clematis is a double flowering purple clematis bred on the Prairies by Mr. Stan Zubrowski. This clematis blooms in late spring/early summer and is one of the hardiest for the Prairies.     

When considering vines, one must include grapes in the possibilities.  Vitis riparia, commonly known as the riverbank grape, is found throughout North America in moist areas such as riverbanks. Riverbank grape is a large, multi-stemmed vine that produces small fruits that are tasty for birds however, not so much for humans. 

For the Prairie climate, the most hardy edible grape vines to grow are ‘Valiant’ and ‘Beta’. Both grape types produce dark blue clusters of grapes that are ready to harvest in early September. The grapes are a little small for fresh eating however, they are highly recommended for juice, jams and jellies. Of the two cultivars, ‘Valiant’ is considered more cold hardy than ‘Beta’. 

Other fruit producing vines that should be considered in the Prairie garden include kiwis and hops. 

The kiwi fruit that will be produced on Prairie hardy vines are much smaller than the kiwi fruit you can purchase at the grocery store.  (2-4cm compared to 7-10cm). To produce kiwi fruit, plant both a male and female kiwi vine. Expect to harvest a few fruit within 3-4 years and by the 7th or 8th year, hopefully, you will have enough fruit to fill a 4 liter pail. 

Hops (Humulus lupulus) is an aggressive vine that requires a support to grow vertically. Even if you don’t want to make your own beer from the fruit, hops are an attractive, interesting plant that provide an excellent privacy screen. Hops die back to ground level each winter and spring back to life at the start of each growing season, growing up to 6m in one season.  

A unique vine that is an excellent talking point in the garden is ‘Dutchman’s Pipe’ (Aristolochia macrophylla). This vine requires a trellis or structure for support. It gets its name from the 4-5cm long yellowish-green flowers that resemble a Dutchman’s pipe. ‘Dutchman’s Pipe’ is recommended for Zone 4 and will require a protected location or extra winter mulch for the Prairies.

American bittersweet (Celastrus scandens) is a woody vine native to North America that produces orange-red fruit that attracts birds in fall and winter. Both a male and a female vine are required for fruit production. Leaves turn an attractive bright yellow in fall.  Do not confuse American bittersweet with Oriental bittersweet (Celatrus arbiculatis) which is similar but a highly invasive vine.

Whether you decide to grow a grape, hops or American bittersweet, always put the supporting structure in place BEFORE planting your vine. Think about how big your vine is going to get in the future and be sure that your support structure is strong enough to support the mature plant. Happy gardening!

This column is provided courtesy of the Saskatchewan Perennial Society
(SPS; saskperennial@hotmail.com). Check our website (www.saskperennial.ca) or Facebook page for a list of upcoming gardening events.

Those pesky beetles are back

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Those pesky beetles are back

Bernadette Vangool

Saskatchewan Perennial Society

My fight with the dreaded lily beetle began early this year, even before the actual Martagon and Asiatic lilies put in an appearance. In my garden they are attracted to the early blooming fritillary. This year they had decimated my checkered lily, Fritillaria meleagris before I caught them in time to save a white fritillary variety that has more robust foliage. As the years go on I have gotten braver, picking them off with bare hands and crushing them underfoot. From mid May to early June, I picked an average of twenty adults a day, mostly around my emerging Martagon lilies which broke ground usually already covered with the now familiar red creatures. Disturbing the soil around the lilies every morning, usually sent several of them scurrying mostly unsuccessfully for safety.

There was a break in activity around the beginning of June, with only the occasional sighting of the adult beetles for the next few weeks, this lulled me into thinking that the problem was over for the year, alas it was not to be. Holes started reappearing in Martagon and Asiatic lily foliage as the grubs hatched out of eggs laid on the underside of the leaves and voraciously devoured their garden salad or lily leaves.

The scarlet lily beetle, red lily beetle or lily leaf beetle (Lilioceris lilii) first arrived in eastern Canada through the importation of plant bulbs in the early 1940s and has been slowly making its way west. It is unmistakable: bright red, with a black head and large black eyes, 8-10 mm in length, oval in shape. The adults overwinter in the soil or under leaf litter, often near the plants they feed on. They emerge in late April or early May and soon settle down to feed and mate.

The female lays 2 to 16 reddish-orange eggs on the underside of lily leaves in an irregular line. The eggs hatch within 8-10 days. The first larvae that hatch are black while later larvae are yellowish-white with a black head. The lily beetle larva deposits its feces on its back (this is called a “fecal shield”) as a protection against the hot sun and to disguise itself from predators. The larvae feed for about 3 weeks and can wreck havoc, capable of devouring entire lily plants. Once mature, the larvae enter the soil, change to an orange colour, and pupate within a cocoon. In 3 weeks they emerge as beetles and continue to feed on lilies until cold weather sets in when they head for the soil to overwinter.

Lily beetles have no natural enemies in North America. In Europe and their native Asia, they are controlled by a parasitic wasp, (Tetrastichus setifer) which lays its eggs in lily beetle larvae and the developing wasp larvae consumes the beetle larvae effectively killing them. While these wasps have been released near Olds College and Calgary in Alberta and in Winnipeg, Manitoba where they have successfully overwintered and seem to control beetle populations, no data is available for Saskatchewan.

As a natural gardener, who does not use diatomaceous earth or pesticides, because they can be detrimental to other insects, my only option is to continue to be vigilant and use my preferred dispatch method. Either picking them manually or flicking them into a jar of soapy water. As a deterrent, I have stopped planting Asiatic lilies and concentrate on the survival of my existing Martagon lilies. My advise to gardeners is to plant lilies in spots that are easily accessible to you, near pathways, so you can inspect them daily throughout the season.

As an end note, last year in September, I noted some damage on two of my hostas, and thought that now, besides thrips and aphids I would have to start looking for snails in my somewhat dry shaded garden. Inspection of the underside of the leaves revealed that in the absence of available lily fodder the evil lily beetle had resorted to a hosta buffet.

This column is provided courtesy of the Saskatchewan Perennial Society
(SPS; saskperennial@hotmail.com). Check our website (www.saskperennial.ca) or Facebook page  for a list of upcoming gardening events.

Big-leafed perennials – Think Foliage!

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Big-leafed perennials – Think Foliage!

Sara Williams, Saskatchewan Perennial Society

Why not go for perennials with large leaves and let their foliage make a statement? Flowers may be fleeting, but the foliage is there for the entire growing season.  If you have the space, go for it. Here are some perennials you might consider.

Bergenia (Bergenia cordifolia) has large handsome leaves that turn a reddish bronze in the fall. Clusters of rosy-pink flowers are produced in early spring. Native to Siberia, it’s very adaptable and will grow in sun or shade. It’s a useful plant for rock gardens, the edge of a pond, edging, or the front of a perennial border. Easily propagated by division.

Marsh marigold (Caltha palustris) is native to the wetlands of Canada as well as Europe. It needs a moist or wet habitat so try to duplicate its natural habitat. Yellow, buttercup-like flowers are produced in early spring above large heart-shaped leaves. Grow in full sun or partial shade with even moisture. It’s ideal for ponds, streams or water gardens. Propagate by division.

Goatsbeard (Aruncus dioicus) is a tall perennial, up to 1.3 m (4 ft.) with an equal spread, producing panicles of cream white flowers in June and July above large, compound feathery dark green leaves. Male and female flowers are on separate plants with the male plants considerably more showy. The leaves turn bronze in fall. It is best grown in partial shade with even moisture. Best placed toward the back of a border, it is easily propagated by division.

Hosta ‘Sum and Substance’ is one of the largest hostas available, with leaves of up to 16 inches, forming a huge mound. Leaf colour varies from light green to chartreuse to gold, depending on the sunlight available. It will grow in full sun to partial shade but needs even moisture.

Ligularia (Ligularia dentata) is a tall perennial (90 to 120 cm/3 to 4 ft) with huge rounded or kidney-shaped basal leaves. Spikes of yellow to orange flowers are produced in July or August. Give them even moisture and a deep soil that has been enriched with organic matter. They will do better in full to partial shade. They are long lived and non-invasive.

Lungwort (Pulmonaria spp.) were once thought to cure lung problems, thus the common name. In the 1400s, it was believed that a plant’s physical appearance indicated its medicinal use. Thus, the large spotted leaves were compared to diseased lungs. Long lived and non-invasive, they prefer an evenly moist soil in full or partial shade. Flowers vary from blue to pink in spring.

Joe Pye Weed (Eutrochium maculatum) is native to North America, including Ontario. It is a bold, architectural plant with good foliage, a height of 150-250 cm and a spread of 90-120 cm. It will grow in full sun to partial shade in evenly moist soil. It has purple flowers in fall.

Delphinium (Delphinium elatum) is an old fashioned plant well adapted to prairie conditions. Up to 120 to 180 cm in height, they have attractive palmate leaves and flowers in white, blue or pink. They do best in full sun with adequate moisture and good fertility and are best placed toward the back of a border.

Rhubarb (Rheum hybridum) is better known for its edible stalks, but the triangular leaves are enormous (but toxic, containing high levels of oxalic acid and anthrone glycosides)! The stalks are widely  used in pies, muffins, cakes and other goodies.

Shieldleaf rodgersia (Astilboides tabularis) has huge, rounded leaves up to 90 cm across and sstilbe-like white flowers in June and July. Native to northern China, they do best in moist soils in partial to full shade.

Astilbe (Astilbe chinensis ‘Pumila’) was introduced from China in 1892. Noted for their large, finely divided leaves, they spread by stolons to form dense compact clumps. Only 30 cm high, they produce fluffy pink flowers in late July, early August. They do best in partial shade in evenly moist organic soil.

This column is provided courtesy of the Saskatchewan Perennial Society
(SPS; saskperennial@hotmail.com). Check our website (www.saskperennial.ca) or Facebook page for a list of upcoming gardening events.

What strawberry should I grow?

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What strawberry should I grow?

Jackie Bantle

Saskatchewan Perennial Society

Strawberries are indigenous to temperature regions in both the northern and southern hemispheres. Wild strawberries have been eaten by people around the world since ancient times.

The modern strawberry that is popular today, Fragaria ananassa, originated from crosses of two New World species of strawberries, Fragaria chiloensis and Fragaria virginiana. The transition from these native species to the modern varieties that we eat today was a long process. The English did most of the early breeding work to develop the ancestors of the varieties we presently grow. 

There are three main types of modern strawberries: June-bearing, Ever-bearing and Day-neutral. The main differences between the different types of strawberries involve the time of year of fruit production and winter hardiness.

June-bearing strawberries produce one strawberry crop/year. Plants flower in spring and fruit is ready to be picked in late June and early July (about a 3 week fruiting time). The runners that the plants send out in fall will produce fruit for the following summer so it is important not to remove these runners.

Common June-bearing strawberry cultivars include; ‘Kent’ (mid-season maturity, high yielding, produces abundant runners, slightly susceptible to powdery mildew), ‘AC Wendy’ (early, one of the top commercial producers), ‘Bounty’ (late season maturity, average yields of larger berries), ‘Honeoye’ (mid-season maturity, firm fruit, produces over a longer time period) and ‘Cavendish’ (mid-season, originated from Nova Scotia, large, firm, dark red fruit with excellent flavour).

Ever-bearing and day-neutral strawberries are often confused as the same type of strawberry, but they are not the same. Ever-bearing strawberries have two distinct fruiting periods: late-June into mid-July and again in late August to mid-September whereas day neutral strawberries also start producing in late-June to early July but continue to produce throughout the summer and into the fall until freeze-up.

Typically, ever-bearing strawberries have smaller fruit size than other types but have better winter hardiness than other strawberry types. Day-neutral strawberries are usually planted as annuals but can be overwintered with mulch in a mild winter.

When planted in spring, ever-bearing strawberries will produce fruit in late summer or fall of that same year. Runners should be left on the ever-bearing fruit plants as they will provide more plants and fruit for the following year.  ‘Ogallala’ and ‘Fort Laramie’ are two common cultivars of ever-bearing strawberries. ‘Ogallala’ fruit can be bitter if produced during hot weather. ‘Fort Laramie’ fruit is large and bright red in colour. With the wider availability of day-neutral strawberries, ever-bearing strawberry types are not very common.

One big advantage of growing day neutral strawberries is that they will produce a good crop of fruit in the same year that they are planted. Additionally, they will also produce fruit on runners that have not rooted, although, runners that develop early in the season should be removed.

Day-neutral strawberry cultivars recommended for northern locations include: ‘Tristar’ (medium sized plants and fruit with good flavour, resistant to verticillium wilt, leaf scorch and leaf blight however, excessive heat creates small fruit), ‘Fern’ (medium to high yielding, firm fruit with good texture, one of the best day neutrals for hardiness), ‘Seascape’ (firm large fruit with good texture, most of the fruit are produced later in summer) and ‘Albion’ (not winter hardy in northern locations, long, narrow, firm fruit, produces fruit later in the season)

Plant new strawberry plants as early as possible in spring after the site is prepared. Strawberry plants can withstand a slight frost. Strawberry plants are often sold in bundles as bare root plants: these are plants that have no soil around their roots and have been stored in cool, moist conditions.

Once you receive the bare root plants, you should plant them in your garden within one or two days. Keep the bare root plants cool and moist until you are planting out: sun and drying wind will kill the tender rootlets. Carry the plants in a pale of water, if necessary, while transplanting. Plant strawberries so that the mid point of the crown is level with the soil surface.  If the crown is covered by soil, the plant will either rot or fail to send out runners. If the strawberry plant is planted too shallow, the crown and roots will dry out. Gently firm the soil around all strawberry plants for good soil to root contact. 

In-row spacing for June bearing strawberries should be 30 cm whereas everbearing and day-neutral strawberries should be planted in double rows 15 cm apart. Runners from the June bearing strawberries will fill in the row. Between-row spacing for all strawberry types should be 1.0-1.5m.

Water in strawberry transplants with 10-52-10 fertilizer. Mix according to label directions.  Thoroughly water the entire strawberry plants immediately after transplanting. For best results, keep strawberry plants well-watered throughout the growing season but especially for several weeks after transplanting.

Strawberries require a healthy soil for good fruit production. For June-bearing and ever-bearing strawberry patches, add a minimum of 8-10cm of compost annually in spring and work into the soil. If you prefer to use fertilizers, apply 200mL per 10 m2 of 34-0-0 after the June crop has been harvested. 

For day-neutral strawberries, fertilize plants in mid-June, mid-July and mid-August with a high nitrogen fertilizer like 34-0-0 at a rate of 50 mL per 10 m2. Water the crop thoroughly after applying any fertilizer to prevent leaf burn on the plants.

Always harvest strawberries when they are ripe red on the plant. Immature strawberry fruit does not ripen after harvesting. Ideal storage for harvested strawberries is 0-2°C and 90-95% relative humidity. This column is provided courtesy of the Saskatchewan Perennial Society. Check our website (www.saskperennial.ca) or Facebook page for a list of upcoming gardening events.

There’s nothing like vine-ripened watermelon and cantaloup from the garden

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There’s nothing like vine-ripened watermelon and cantaloup from the garden

Jackie Bantle

Saskatchewan Perennial Society

Cantaloupe and watermelon are members of the Cucurbit family of plants.  This family also includes pumpkins, cucumbers and winter squash however, of all of these vine crops, watermelon and cantaloup are the most challenging to grow during the relatively short growing season in Saskatchewan. 

Cantaloup and watermelon require soil temperatures of at least 15°C for seed germination and optimal growth to occur.  To get a head start on the season, it is best to start plants indoors and transplant outdoors once the outdoor soil and air temperatures are at least 20˚C.  Cucurbits (ie. vine crops) do not like to have their roots disturbed: germinate seeds in Jiffy 7’s and transplant the Jiffy 7 directly into the soil – without disturbing the plant roots. 

Cantaloup and watermelon transplants should only be 10-14 days old before planting out (cotyledons have emerged along with only one or two true leaves).  Larger transplants will experience transplant shock when they are planted outdoors: plants will not grow for several weeks (or at all) depending on the level of transplant shock they experience.  Be sure to harden off transplants at least 5 days prior to planting out.  Start by setting the transplants outdoors in a protected, partially shaded location for several hours/day.  Increase the length of time spent outdoors as the hardening-off period continues.  When transplanting into the garden, avoid extremely hot or windy conditions.

Instead of starting transplants, it is possible to direct seed cantaloup and watermelon directly into the garden however, when direct seeding, I recommend laying down clear or black plastic mulch along the soil at least one week prior to seeding.  Lay the plastic mulch (approximately 1mil thickness) onto the garden soil and secure the edges of the plastic with soil, rocks or heavy boards.  It is important that the plastic mulch is pulled tightly against the soil to discourage weed growth under the plastic and to effectively heat up the soil.  Punch holes in the plastic (approximately 5cm in diameter) and bury seeds about 1cm deep in the holes.  Lightly water in the seeds.  Plastic mulch can also be used in conjunction with transplants: plant transplants in the holes rather than the seeds.  When transplanting, cover the Jiffy 7 peat pellet completely with soil to prevent the pellet (and the transplant) from drying out.

All cucurbits benefit from clear perforated plastic tunnels or crop covers.  Use crop covers with a weight of 0.5 oz/yd2 or that allow at least allow 85% light transmission.  Be sure that the perforated plastic is supported by wire hoops as clear plastic directly on plant leaves will burn the leaves.  Cover seeded rows or transplants with crop cover or plastic tunnels immediately after seeding or transplanting.  Leave covers in place until flowers are formed on the plants or until the 3rd week in June, whichever is later. Remove covers to allow pollinators to pollinate the flowers. After fruit has set, crop covers can be replaced, especially if outdoor temperatures are cool (mid-July).  Protect the plants from frost by using crop covers or heavier frost blankets.

Watermelon and cantaloup plants have both male and female flowers on their vines.  Male flowers are the first flowers to appear on the plant.  It is normal to observe some of these initial male flowers  falling off.  Female flowers appear 7-10 days after the male flowers start to appear.  The female flowers are identified by what looks like a small fruit where the stem meets the base of the flower. 

Poor fruit set on plants can occur for several reasons:  lack of female flowers on the plant and/or poor pollination by bees or insects.  Poor pollination can be due to a lack of pollinators, extreme heat making pollen sterile or poor weather (cold, rainy, cloudy) that discourages bees and other insects from flying around to pollinate.

During the growing season, provide 2.5cm of water per week early in the season.  By mid-July, provide 2.5cm of water, twice weekly. Apply soluble 20-20-20 fertilizer weekly prior to fruit set, and bi-weekly after fruit set.  Apply fertilizer according to label directions.

Cantaloupe is ready to harvest when the fruit skin looks slightly orange in color and the stem end of the fruit easily slips free from the vine. (full slip) Once harvested, the cantaloupe is best stored at cool room temp (10°C); 15°C if picked slightly immature. After the cantaloupe is cut, store cut in the fridge at 5°C.

Determining when a watermelon is mature can be challenging.  Mature watermelon fruit will sound hollow when they are tapped with your fingers; the tendril closest to the stem end that attaches to the fruit will be dried up; the skin surface of the watermelon loses its shine and becomes dull, and the rind on a mature watermelon fruit will be difficult to puncture with a thumb nail.  Watermelon fruit does NOT slip from the vine like cantaloupe.

Once harvested, watermelon can be stored at room temperature for several days.  Long term storage of watermelon should be in the fridge at 5°C.

Not every cantaloup and watermelon cultivar are created equal.  Look for varieties that will mature in 75 days or less. ‘Athena’, ‘Goddess’, ‘Tasty Bites’ and ‘Pixie’ cantaloup are recommended cantaloup cultivars to try.  ‘Sugar Baby’ (red), ‘Favorite Ball’ (red seedless), ‘Sangria’ (red) and ‘Yellow Doll’ (juicy, sweet, yellow flesh) are all recommended as watermelon cultivars to try in Saskatchewan.

By growing the best cultivars recommended for our region along with some ‘tricks’ to enhance the growing conditions, almost any Saskatchewan gardener can experience the unmatched flavour of a vine ripened watermelon or cantaloup from their own garden.

 This column is provided courtesy of the Saskatchewan Perennial Society (SPS; saskperennial@hotmail.com). Check our website (www.saskperennial.ca) or Facebook page for a list of upcoming gardening events.

An update on growing Sweet Potatoes in Saskatchewan

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An update on growing Sweet Potatoes in Saskatchewan

Jill Thomson

Saskatchewan Perennial Society

In 2024, I was asked to write an article on growing sweet potatoes in Saskatchewan, which I did in the fall, as we tried several new techniques in the summer of 2024. I have included much of the information from that article, with the latest news for this season.

We have been growing sweet potatoes in Saskatoon for about 7 years, harvesting enough tubers that we can store them and eat some each week until the New Year. The harvest from last year has finally been eaten and I have started plants from some of the small, sprouted tubers, to provide slips for this season.

Sweet potatoes (Ipomea batatas) are native to tropical America and are related to the Morning Glory flowering plant. They are not closely related to our common potatoes (Solanum tuberosum) or yams (Dioscorea spp). Although the white fleshed sweet potatoes may be called yams in the grocery store, they are mis-labelled. True yams are usually grown in Africa and Asia, not in North America.

Sweet potatoes require a longer frost-free period than is normally experienced in Saskatchewan and extra care must be taken to give them warm soil and adequate water during the summer, and to protect them from frost in late spring or early fall. They are usually planted as shoots (slips) taken from parent plants, that have been placed in water for 5-6 days, until they have produced roots. We used to buy rooted slips from seed companies in Eastern Canada, but for the past few years we have kept plants growing indoors through the winter, which can be used to produce slips in the spring. This spring I have also started plants from the sprouted tubers, to plant out in the bed in June.

Originally, we tried about 8 of the cultivars available, but for the past few years we have grown only Covington and Japanese Yam (really a sweet potato). Covington has a brown skinned tuber with orange flesh, which I prefer to the red skinned, white fleshed Japanese Yam. In 2024 we tried a new cultivar, Radiance, which is about 3 weeks earlier to mature than other available varieties. Radiance was bred in the Vineland Research and Innovation Centre, Ontario, and sufficient numbers of slips were produced in 2024 by an Alberta company, for sale to Canadian growers. Radiance did very well in our garden but unfortunately the Alberta company did not have a good crop for producing slips in 2025. However, they are now growing a second new cultivar, Luminance, and have sufficient slips of this variety to supply in place of Radiance. Radiance produces orange-fleshed tubers, which I prefer, but I am willing to try the white-fleshed Luminance.

It is important to prepare a suitable growing environment for your slips. We dig our soil bed in mid May, adding in compost, and then making a raised bed, the width of 1 row, like a hilled potato row, with a flat top and slanted sides. We run 2 soaker hoses on each side of the top of the row, cover it with a strip of plastic that is anchored with soil in the depressions each side of the row. You can use either clear or black plastic, as it is needed to warm up the soil. Black plastic has the advantage of reducing weed growth, but it is not difficult to loosen the plastic to remove weeds early in the season, and the dense growth of the sweet potatoes will crowd out the weeds by mid-season. We plant the slips in the centre of the row, through slits made in the plastic, at about 30cm apart (Photo 1). In 2024, the slips were encouraged to poke up through the slits, but the weather was dreadful, cold and windy for about 2 weeks, and the new plants were very slow to develop. Luckily, the season was long, with some hot spells, and eventually the plant tops grew vigorously as we could keep them well watered with the drip irrigation (Photo 2). 

Harvest is exciting, as you really don’t know what to expect. The green leaves and stems are cut off at ground level so the plastic can be rolled back, and the soil is dug away carefully. Most plants have a cluster of tubers hanging down near the main stem. Occasionally the roots go searching for water, and then a tuber will be found away from the main plant. In 2024, our biggest tubers were produced on the Radiance plants. These tubers were 20-30 cm and weighed 600-700 gm each (Photo 3), but usually tubers range from about 300g to unusable thin roots, about 20- 30cm long. We keep a few plant tops attached to tubers initially, so we can identify the cultivar, and save a few stems to grow on for winter plants.

Harvested tubers are placed in crates with good air circulation, but initially the crates are enclosed in large, plastic bags, for about 3 weeks at high room temperature, being careful not to allow high humidity, and moisture build-up. The bags are then removed, and the cured tubers kept in the crates at room temperature for the remainder of the winter. We usually eat any damaged tubers and the smaller tubers first. Some of the smaller tubers can be kept till spring when they will often sprout and can be used to produce new slips.

Mice (or voles) like the tubers and in our first year several of the biggest Japanese Yam tubers were completely hollowed out. In 2024 the rodents again ate tubers, and interestingly they again selected Japanese Yams and did not eat the orange fleshed tubers. This may have been a chance selection, I have no data on mice preferences! We have only noticed insect pests once, about 6 years ago, when there were small green caterpillars (identified as caterpillars of the morning glory plum moth) eating new leaves. One spray of Bt insecticide was sufficient to reduce the caterpillar population significantly. We did not notice an impact on yield.

The book “Sweet Potatoes for the Home Garden” by Ken Allan, gives excellent information on growing this crop, and describes most of the older cultivars. There is also an article in The Gardener magazine that provides information on cultivation of sweet potatoes in the prairies (Summer 2017, Vol 23 Issue 2). Now we are growing Canadian varieties, and slips are being produced in Alberta, there will likely be more information on-line about growing sweet potatoes in Canada.

Jill Thomson is a plant disease specialist (retired) who enjoys gardening in Saskatoon with her family, including the dogs. This column is provided courtesy of the Saskatchewan Perennial Society (saskperennial@hotmail.com). Check our website (www.saskperennial.ca) or Facebook page for a list of upcoming gardening events.

Growing a Big Pumpkin: Good Genetics + Good Environment

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Growing a Big Pumpkin: Good Genetics + Good Environment

Jackie Bantle

Saskatchewan Perennial Society

Howard Dill is perhaps the most famous large pumpkin grower of the last century. Mr. Dill is known for winning four straight world titles for growing the largest pumpkin. His famous Dill’s Atlantic Giant pumpkin seed is a ‘must have’ for those of us who are trying to grow a gigantic pumpkin. 

To successfully grow a large pumpkin in our relatively short growing season, start pumpkin transplants indoors about 2 weeks before you plan to transplant outdoors. Pumpkin seeds should be seeded in peat pots or Jiffy 7’s so that roots will not be disturbed when transplanted. Two weeks is ample time to produce a pumpkin transplant. Transplants that have more than two true leaves will not transplant well.  Avoid long, leggy transplants. The first two leaves to emerge from the seed will be the cotyledons, after that, the first true leaf will emerge. 

It may be just as easy to direct seed pumpkins into the soil. When direct seeding, ensure that the soil is warmed up to at least 20°C. Warm temperatures encourage speedy germination and quick emergence.  Place a clear plastic sheet on the ground.  Tightly secure the edges of the plastic with soil or heavy 2 x 6 boards: this will warm up the soil early in spring.  Pumpkin plants should be spaced 3m2/plant apart. Poke small holes (about 5cm diameter) into the plastic sheet and direct seed the pumpkin seed into the soil (about 2cm deep).  Water the seeded holes lightly. As seedlings emerge, they will grow out of the plastic through the holes. The clear plastic can remain on the soil throughout the season as it will continue to warm the soil and encourage good pumpkin vine growth. 

Avoid using organic mulch such as grass clippings or leaves around the base of the pumpkin plant as this will reduce soil temperatures and slow plant growth. As soon as seedlings have emerged or immediately after transplanting, water in the transplants or tiny seedlings with a 10-52-10 soluble fertilizer mixed according to label directions. Apply 20-20-20 soluble fertilizer every two weeks until fruit set (late June).  After fruit set, fertilizer weekly with 20-20-20 fertilizer. 

Pumpkin plants require a lot of water.  Initially, apply 2.5cm of water/week. By mid-July, increase watering to 2.5cm of water, twice weekly. 

Pumpkins love heat. Agricultural crop covers warm up the air and soil around the plants. Place crop covers over the plants as soon as they are transplanted or emerged from the soil.  Agricultural crop covers can be purchased at your local garden center and have different weights. Some crop covers are referred to as ‘frost blankets’: these are a bit heavier weight and can limit the amount of light reaching the plant under the cover. Covers that have a weight of 0.5 oz/yd2 are recommended for large pumpkin production:  these covers will warm air temperatures around the plant and allow 85% light transmission.  The only time you must remove crop covers is during flower pollination (3rd & 4th week in June) and to weed the garden.

Pumpkin fruit is produced by cross pollination. The first flowers that appear on the pumpkin plant are male flowers. The pollen is ready to use from these male flowers when it comes off easily from the stamens onto your fingers. Female flowers will appear several days to one week after the male flowers.  Female flowers are very obvious in that they have a small little pumpkin located beneath the flower petals and the stem. To pollinate the female flower, carefully remove the male flower from the plant and rub the stamens over the interior parts of the female flower. Follow this same process for several flowers. After several days, the female flowers that are pollinated will continue to grow whereas the tiny fruit on non-pollinated female flowers will wither and die. You can leave the pollination process up to bees and other pollinators however, they may not be as efficient as you. 

To produce a giant pumpkin, once the fruit reaches the size of a basketball, thin pumpkins to one fruit per plant. Remove any other developing fruit and flowers throughout the season. Removing excess fruit and flowers focuses all of the plant resources into producing one giant fruit.    Replace crop covers after fruit set. 

As the pumpkin grows and matures, minimize the length of the vine: the main stem should not exceed 5m while the secondary stems should not exceed 3m. Throughout the season, the weight of the pumpkin will cause the fruit to flatten. If possible, turn the pumpkin slightly to ensure a more rounded shape. Be careful not to damage the fruit or the vines during this process. Moving a very large pumpkin on the vine will not be possible later in the season.  

Not all pumpkin cultivars are created equal.  If you want to grow a record breaking pumpkin, start with seed from a big pumpkin.  ‘Dill’s Atlantic Giant’ is probably the best know cultivar for growing record-breaking pumpkins.  If you happen to grow your own large pumpkin, maybe you can sell the seed.  Some websites are selling giant pumpkin seeds at $349.00 for one seed!

This column is provided courtesy of the Saskatchewan Perennial Society (SPS; saskperennial@hotmail.com). Check our website (www.saskperennial.ca) or Facebook page (www.facebook.com/saskperennial) for a list of upcoming gardening events.

What’s new in this year’s newly released Saskatoon Tree Tour booklet

Sask Perennial Society
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What’s new in this year’s newly released Saskatoon Tree Tour booklet

Bernadette Vangool

Saskatchewan Perennial Society

Early this year the SOS Trees Coalition released its Saskatoon Tree Tour booklet, with new destinations of remarkable trees to visit within Saskatoon’s city limits. SOS Trees Coalition grew out of the SOS Elm Coalition which was founded in 1992. Citizens were concerned about the future of American Elm trees within the city. There was the very real threat of Dutch Elm Disease (DED) which had invaded south-eastern Saskatchewan. With the aging of the city’s original tree canopy and many infill projects, the scope of the organization widened to include other species at risk due to new threats such as climate change, urban expansion and the aging inventory of trees.

This year’s edition of the Tree Tour does not disappoint – with a new section added on the proper planting of trees. It clearly outlines the benefits of trees and why urban trees matter. As well, It features twenty-seven distinctive Saskatoon trees. Each tree has one page dedicated to its description, including a large photograph showing the tree form and a smaller one featuring a distinct leaf or fruit. This is great for the new tree enthusiast, helping them identify a particular species in the general landscape. Each description also includes information about its native habitat and its usefulness, past and present. For example, the bur oak’s fruit, the acorn, is loved by squirrels, whereas humans would use the Douglas fir in home building and boat construction.

Each featured tree has its address included, and at the bottom of the page, an alternate location is mentioned for most specimens. The centre of the publication has a map, giving you an overview of tree locations, to more easily plan your driving route. And for those of us walking, it is also easy to find groupings of trees for your personal walking tour.

Another innovation this year, is the section that deals with tree destinations, where many trees can be observed in one visit. These include; Woodlawn Cemetery, where Memorial Avenue, begun in 1923, was planted with stately elms commemorating Saskatoon soldiers who died in the First World War; Patterson Gardens, established in 1966 to test hardiness of trees to local conditions; Richard St. Barbe Baker Afforestation Area, established in 1972 and named in 1979 after Richard St. Barbe Baker, a great forester and environmental pioneer; University of Saskatchewan Campus with a unique collection of trees which was curated by Dieter Martin, the Grounds Supervisor from 1957 to 1976; Innovation Place, which includes the Boffins Garden; and last but not least the Saskatoon Forestry Farm Park, formerly the Sutherland Forest Nursery Station, which distributed 147 million tree seedlings during its history and now is a Saskatoon park, which also houses the Zoo.

A page on Dutch Elm Disease, which is fatal to the American Elm, is included, describing its symptoms and ways to discourage its spread. This has become urgent – Saskatoon had a huge increase of confirmed cases of DED in 2024, causing 18 mature elms to be removed.  The suspected cause was illegal elm firewood brought into the city from elsewhere.

Another addition this year is a discussion around planting native trees and shrubs to enhance your natural landscape. Native species will benefit native pollinators and can be successfully integrated into your garden. References to Wild about Saskatoon which has plant list resources for starting a native garden and the Native Plant Society of Saskatchewan which has a “grow me instead” list of plants to replace some perennial plant species which have become invasive.

With Arbor Week in Saskatoon fast approaching, be sure to pick up your new copy of the Tree Tour at one of the following locations: Steep Hill Food Coop on Broadway Ave., Early’s on Lorne Ave., the Western Development Museum, Wild Birds Unlimited and Dutch Growers.  Other locations for booklet pick-up and a copy of the new Tree Tour will be available for download on the SOS Trees website https://www.sostrees.ca in the near future.

To kick off Arbor Week, the Friends of the Forestry Farm House are having a walking tour of the Forestry Farm Park starting at the Superintendent’s Residence at 2.30 pm on Sunday, May 25. If you are interested in local history, you can also view the house between 1.30 and 2.30pm. On Arbor Day, May 30, 9am till noon, SOS Trees volunteers will be helping grade 5 students of Ecole Henry Kelsey plant 60 trees and shrubs in Pierre Radisson Park. Thank you to the City of Saskatoon Parks Department for assisting with this project and for watering the new plantings for three years to help the trees become established. In closing the week, the Saskatchewan Perennial Society has a Labour and Learn scheduled for May 31from 9am until noon. Join us to help clean up the Robin Smith Meditation Garden and Heritage Rose Garden at the Forestry Farm Park. The crab apple blossoms in the garden and the park are usually spectacular at this time.

This column is provided courtesy of the Saskatchewan Perennial Society
(SPS; saskperennial@hotmail.com). Check our website (www.saskperennial.ca) or Facebook page (www.facebook.com/saskperennial) for a list of upcoming gardening events.

Dwarf Conifers for the Mixed Border

Sask Perennial Society
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Dwarf Conifers for the Mixed Border

Sara Williams

Saskatchewan Perennial Society

Let’s begin with some definitions. A “mixed border” consists mainly of herbaceous perennials (those that die back to ground level each winter) but may also include hardy and tender bulbs, annuals, biennials, vines, and coniferous and deciduous shrubs. Together, these plants give the border greater interest with their different heights, textures, and colours, and an extended season that perennials alone could seldom accomplish.

“Dwarf conifers” generally range in height from 0.3 m (12 in.) up to 2 m (6 ft.), but even at their largest remain considerably smaller than their “normal” cousins. They vary in size, colour, form and texture; give a certain weight and substance to the border through spring, summer and fall; and extend its interest into winter (assuming that they are not buried in snow.)

They generally require less maintenance than perennials, and as I become older this feature assumes greater value. The following have proved hardy in my zone 2b garden. Most have been selected for their limited spread as well as height; they are not “groundcovers” that   will continue indefinitely. Some may eventually (after 40 years) become larger, but that is generally a problem for “the next owner.”

Dwarf balsam fir (Abies balsamea ‘Nana’) – (0.6 x 1. m/2 x 3 ft.) is attractive, densely branched, deep green and globular.

‘Mother Load’ juniper (Juniperus horizontalis ‘Mother Lode’) – (10-15 cm x 1 m/4-6 in. x 3 ft.), is a sport of J. wiltonii, with unique golden variegated foliage.

Nest spruce (Picea abies ‘Nidiformis’) – (1 x 1 m/3 x 3 ft.), a dwarf form of Norway spruce, has a dense, flat-topped, globular form with a slight dip in the centre resembling a bird’s nest, and bright green needles.

‘Ohlendorfii’ (Picea abies ‘Ohlendorfii) – (2 x 1.3 m/6 x 4 ft.) tends to be somewhat more informal, irregular and lumpy in form (a characteristic I can now readily identify with) with dark green foliage.

Dwarf Alberta spruce (Picea glauca ‘Conica’) – (2.5 x 1.5 m/8 x 5 ft.) is widely available but seldom over-winters well on the prairies. Place it where it will not become desiccated by the winter sun: on the north side of a fence or building. (In its native habitat it’s generally totally buried under the snow.)

Dwarf globe spruce (Picea pungens ‘Glauca Globosa’ – (1.2 x 1.8 m/4 x 6 ft.) lends the border a lovely silvery blue and a sense of substance throughout the year. It can be occasionally sheared if a smaller size is desired.

Dwarf black spruce (Picea mariana ‘Ericoides’) – 30-45 x 30 cm/24-30 x 24 in.), is low and dense with tiny soft blue-green needles and a mounded form.

‘Slowmound’ mugo pine (Pinus mugo ‘Slowmound’) – 0.6-1.2 x 1.3 m/2-4 x 4 ft.) Although its eventually size may seem intimidating, the name says it all: it grows very slowly. It has a rich green foliage.

‘Danica’ dwarf cedar (Thuja occidentalis ‘Danica’) – (0.6-0.8 /2-2.5 ft. in height and spread) is slow growing and globe-shaped with glossy emerald green foliage held in a vertical plane. It may become bronze tinged in winter and is best placed in a sheltered location.

‘Little Gem’ dwarf cedar (Thuja occidentalis ‘Little Gem’) – (0.6/2 ft. in height and spread) is slow growing, dense and globe-shaped, with glossy, dark green foliage with a unique slightly twisted texture.

‘Little Giant ‘ dwarf cedar (Thuja occidentalis ‘Little Giant’) – (0.5/1.5 ft in height and spread) is the smallest of the dwarf cedars, very dense, with soft, rich green foliage.

This column is provided courtesy of the Saskatchewan Perennial Society (SPS; saskperennial@hotmail.com). Check our website (www.saskperennial.ca) or Facebook page (www.facebook.com/saskperennial) for a list of upcoming gardening events.

Congratulations Dr. Bob Bors!

Sask Perennial Society
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Congratulations Dr. Bob Bors!

Bernadette Vangool

Saskatchewan Perennial Society

This year, six individuals are being recognized for their lifetime achievements in agriculture and will be formally inducted into the Saskatchewan Agricultural Hall of Fame at a ceremony this weekend at Prairieland Park.

Frank and Gerry Bourgault are recognized for their entrepreneurial spirit and innovation at Bourgault Industries, Harold Martens for his work in agriculture as an elected Member of the Legislative Assembly, Dr Grant Royan of Sherwood Animal Clinic, Regina, as a mentor for many veterinarian students and Bill Wilson for his work in media as a reporter on agricultural news and trends.

Last but not least, is Dr. Bob Bors who for over twenty years headed the Fruit Program at the University of Saskatchewan. His fruit plants are grown by home gardeners and commercial fruit growers alike in Saskatchewan, Canada, the United States as well as in Europe.

Dr. Bob Bors, who was educated in Maryland and received his Ph. D. from the University of Guelph, arrived in Saskatoon in the middle of winter of 1999, in -40 C. But undeterred, he persevered and settled into the cooler northern weather.

No man is an island, and he soon made the acquaintance of Rick Sawatzky, a technician at the University of Saskatchewan, who was working with sour cherries and honeyberries. In the 1970s Rick had received stock of sour cherries from Les Kerr who had been breeding them for 20 years. Rick crossed the ‘Kerr Easy Pick’ with ‘North Star, a sour cherry introduced in Minnesota. The result was ‘Sk Carmine Jewel’ the first sour cherry introduced by the University of Saskatchewan in 1999.

Bob arrived in this fertile environment. He recognized Rick as the “father of the cherries’ and himself as the ‘honorary god-father’. Bob did further testing on cherries and developed protocols for their tissue culture. He gathered more breeding material and made additional crosses. Selections were made based on flavour, size, ease of pitting as well as the possibility of mechanical harvesting, which would make the cherries a viable option for commercial growers.

In 2003, the University of Saskatchewan introduced the Romance series of cherries. Of this series, Bob’s preference were ‘Romeo’ and ‘Juliet’. Others in this series included ‘Cupid’, ‘Valentine’ and ‘Crimson Passion’.

Besides his passion for cherries, Rick Sawatzky also was working with what we now know as haskaps, previously called honeyberries or blue honeysuckle. Bob had his first taste in the year 2000 during a field tour led by Rick. He became quite excited. The tour was held in June and already the berries were ripe on the bushes.

Bob’s excitement never did wane and he carried out extensive work, researching different suppliers and breeders and varieties collected across the globe, first from Russia, then Japan, Poland as well as stock shared by Dr. Maxine Thomson from the Oregon State University.

This work culminated in the release of several early to midseason varieties in 2007: ‘Borealis” and ‘Tundra’ and the Indigo series. From 2014 to 2016, the Boreal series were released. They are a later ripening group, and I have observed that berries tend to stay on the plant better than the early releases – which is great for commercial operations.

While the early years of cherry and haskap development was funded by grants, since 2013 over 75% of program funding has come from plant patent royalties derived from new introductions.

One of Bob’s most important contributions is extension: sharing knowledge with home gardeners as well as commercial growers through workshops, talks, plant sales, and plot tours at the University and through articles on cherries and haskaps. He has provided technical information on sour cherries and haskaps at meetings and seminars across North America. During his tenure as head of the Fruit Program the University of Saskatchewan has become known as the world’s foremost breeding program for haskaps.

Bob believes that grassroots connections are crucial to successful fruit program development. Besides working with sour cherries and haskaps he also ensured that other northern fruit breeding stock is maintained in the ‘Prairie Fruit Gene Bank’

This column is provided courtesy of the Saskatchewan Perennial Society (SPS; saskperennial@hotmail.com). Check our website (www.saskperennial.ca) or Facebook page (www.facebook.com/saskperennial) for a list of upcoming gardening events.

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