By Bernadette Vangool
Saskatchewan Perennial Society
Few roses are more rewarding than the Rugosas (Rosa rugosa). Beginning gardeners can enjoy these robust additions to the perennial border without worrying unduly about the many things that can go wrong when growing roses. Rugosas are hardy through our freezing winters and are relatively pest and disease free. On top of these redeeming qualities, they often offer repeat or continuous bloom, providing colour, fragrance and interest throughout the growing season. When not in bloom, the wrinkled dark green foliage fills out a perennial border and in fall plants are adorned with beautiful rose hips.
To keep your rose shrubs looking healthy, prune out the old canes (at ground level) and any winter die back in late May. In summer, remove the spent blooms until about mid-August. This will encourage repeat bloom but delay the production of rose hips. When pruning always make the cut just above an outfacing bud.
Plant your roses where they’ll receive six or more hours of direct sunlight. Anything less results in less bloom as well as the slow deterioration of the plant. Afternoon sunshine is best as it is generally hotter. Avoid planting roses too close to foundations as those areas tend to get too hot and too dry and do not provide enough air circulation. These conditions stress the plants and stressed plants are more prone to pests and diseases.
When planting, dig the hole deep and wide, at least twice the size of the pot, and in clay soil even larger. Throw a handful of bone meal in the hole (I often don’t bother with this step), fill the hole with half soil and half compost or composted manure. If working with clay soil, discard the clay soil and replace it with half and half good top soil and compost. If you bought a potted rose, plant it at the same depth as in the pot. Gently untangle the roots on the sides of the pot if required, to ensure that they will grow into their new environment.
Most Canadian hardy roses are grown on their own rootstock. If you bought bare root roses, often available in early spring, soak them overnight in water. Some of these may be grafted and will show a swelling or knobby area where the graft union is located. This should be placed about 10 cm below the soil line. When planting bare root plants, mound good soil at the bottom of your planting hole over which to drape the roots while slowly filling and gently tapping the soil around the plant. Leave a small depression/dyke around the rose for ease of watering. Water thoroughly to ensure no air pockets exist around the roots. Mulch after watering to keep the roots cool and retain moisture.
There should be no need for fertilizer the first year. In subsequent years, move the mulch away from the base and top dress the area around the rose with compost and fertilize with a granular fertilizer with a higher middle number (phosphorus). If you tend to baby your roses, you can fertilize lightly once a month starting in May. Do not fertilize after the end of July as the rose needs to go dormant for winter.
Water your newly planted rose every two to three days, to the depth of their root system and a bit beyond, to encourage deeper rooting. Water them once a week thereafter when there is no rainfall. Unless you use drip irrigation, it is best to water roses and perennials in the early morning. Less water is lost to evaporation and the plants have a chance to dry out before nightfall. Once established, roses are quite drought tolerant.
Rugosa roses you may want to try;
Pavement series: ‘Purple Pavement’ with purple-crimson blooms and ‘Snow Pavement’ with white blooms were introduced from Germany and are typically 1.2 x 1 m. They can be used as a low hedge if pruned to 50 cm high each spring.
‘Henry Hudson’ has white blooms and is 1.2 x 1 m. It was part of the Explorer series, introduced 1976.
‘Reta Bugnet’, introduced by Georges Bugnet from Alberta in 1958, is 1.2 x 2 m and has pink buds that develop into white blooms.
‘Therese Bugnet’, also a Bugnet introduction (1950), is 2 x 2 m, with red buds that open pink.
Bernadette Vangool is a long-time member of the Saskatchewan Perennial Society.
This column is provided courtesy of the Saskatchewan Perennial Society (SPS; firstname.lastname@example.org ). Check our website (www.saskperennial.ca) or Facebook page (www.facebook.com/saskperennial). All Saskatchewan Perennial Society events are ‘ON HOLD’ till further notice.