by Erl Svendsen
Hostas are the workhorses of a shade garden. They add colour, texture and interest. Most are hardy, take little care, have few pests on the Prairies and are well-behaved by staying where they’ve been planted. Hostas range in size from dwarfs to giants; leaf colour in blues, greens, yellows, whites/creams and in variegated combinations; leaves may be smooth, shiny, glaucus, wrinkly (reticulated), long and skinny, or wide and rounded; and flower colour is mostly limited to shades of pink, lavender and purple.
But with 1000s of available cultivars and dozens more introduced every year, how do you choose the right one? The American Hosta Growers Association (www.hostagrowers.org) has been trying to help by highlighting a Hosta of the Year, a program they started in 1996. Selected cultivars have a proven track record and should be available in most garden centres at a reasonable price.
This year’s winner, ‘Rainbow’s End’ (natural sport of ‘Obsession’) was selected by Hans Hansen and introduced in 2005 by Shady Oaks Nursery in Minnesota. Like all hostas, ‘Rainbow’s End’ is a mound-forming herbaceous perennial, consisting mostly of leaves arising from very short, compressed stems. At maturity, the medium-sized mounds are about 11 inches (28 cm) tall (not including flowering stalks) with a 21-inch (53-cm) spread.
When the leaves of ‘Rainbow’s End’ first emerge (5-7 leaves per shoot or ‘eye’), they are shiny and predominantly yellow with dark green margins and random light and dark green streaks shooting into the leaf’s centre. As the leaves age, they lose some of their shine and the yellow matures to creamy-white. Like snowflakes, the variegation is so irregular that no two leaves look alike. This is in contrast to its progenitor, ‘Obsession’, which has dark green margins and subtle light and dark green variegation. Leaf blades have a wide rounded base and come to slightly downward curled point, about 4 inches (10 cm) wide and 6 inches (15 cm) long. The petioles add an additional 6.5 inches (17 cm) to the overall leaf length.
In Minnesota, flowering begins in early August and continues for about three weeks. About 15-20 pale violet, unscented, tubular flowers are produced on attractive, showy red flowering stems that add an additional 5-8 inches (13-20 cm) in height to the mound. After flowering, remove the flowering stalks close to their base (use scissors or secateurs) to keep the mounds looking tidy.
For best results, plant in light to dark shade, in the front to middle of your border. ‘Rainbow’s End’ can be planted as a single specimen, used as a border or groundcover, or planted as a bright ribbon running through your perennial border to draw your eye to other interesting features in your garden. Your soil should be well-amended with compost or other organic matter. Add a 3-4 inch (7-10 cm) layer of mulch to retain soil moisture and to protect the crowns from summer’s heat and winter’s cold. Hostas like to be kept evenly moist but not wet.
Erl gardens in Saskatoon and tweets about on occasion @ErlSv.