Great Plant Picks, the new plant awards program sponsored by the Elisabeth C Miller Botanical Garden in Seattle, has endorsed almost sixty-five plants for 2002. The tree and shrub selections were discussed in the previous issue of Pacific Horticulture (January 2002). The majority of the winners this year are in the perennial and bulb category. The perennial and bulb selection committee, chaired by Alex LaVilla of Swansons Nursery in Seattle, is an enthusiastic group of specialty growers and nursery staff with a passion for excellence and horticultural variety.
Great Grasses, Seductive Sedges, and Luscious Rushes
The popularity of ornamental grasses continues, but, with so many to choose from today, the interested gardener is challenged to find the one that will best suit the garden situation available. It is not surprising, then, to find several grasses, sedges, and rushes among this year’s Great Plant Picks. Several of the grasses chosen offer strong foliage contrast and are shade tolerant, making them ideal for lightening up shady corners common to Northwest gardens.
The shade tolerant variegated tufted sedge (Carex elata ‘Aurea’) is bright yellow with dark green variegation. It prefers a moist location and is an excellent plant for color contrast in the border. Another shade tolerant selection is golden Japanese forest grass (Hakonechloa macra ‘Aureola’). This graceful deciduous grass is bright yellow with narrow green striping. It is slow to spread but definitely worth the wait: mature clumps resemble low cascades of yellow green froth in the landscape. A small grass, it develops beautiful reddish tones in autumn.
Silver and blue add elegance and a sense of calm to the garden. Blue oat grass (Helictotrichon sempervirens) is beautiful used either alone or massed in the mixed border. Approximately three feet high, blue oat grass has a fine texture that is striking with purple foliage or flowers. It produces golden seed heads in early to midsummer. Preferring sun, blue oat grass is drought tolerant once established.
Miscanthus sinensis ‘Morning Light’ features slender bluish green leaves with white margins, creating a silvery sheen in the border. It produces arching seed heads on stalks to four feet high in late summer and early autumn. A clump-growing grass, it is ideal as a mixed border specimen.
All gardeners appreciate a low maintenance plant. Carex morrowii ‘Ice Dance’ is a trooper of a sedge, requiring little care in return for its bold variegation of cream and grayish-green. Its rhizomatous growth habit makes it a fine groundcover for the front of the border. It will grow well in both dry and moist shade, but can tolerate sun. If that was not enough, it is also evergreen.
Acorus gramineous ‘Ogon’ is another splendid variegated plant, this one with gold to chartreuse cream variegation on green leaves. This is an excellent sweetflag if you are looking for an accent plant. It stays small, making it a good, fast-growing groundcover. ‘Ogon’ prefers a wet condition in full sun to part shade, and would look splendid at the edge of a pond or bog.
Variegated purple moor grass (Molinia caerulea ‘Variegata’) is considered one of the lowest maintenance grasses available. The foliage is dark green with creamy stripes, which in itself makes for an appealing plant. In addition, the purple seed heads put on a colorful show in summer. Slow growing to two feet high, it can be used singly or in masses in the mixed border.
Among the taller grasses, used to create drama and tension in the garden, is pheasant’s tail grass (Anemethale lessoniana, formerly Stipa arundinacea). This is an elegant green grass with long-lasting seasonal interest. From mid-summer to autumn it produces three-foot-long panicles of seed heads. In late summer, the foliage is streaked with orange brown tones, and in winter, the entire plant turns bronze. It can be evergreen in milder gardens and is tolerant of dry shade once established.
Perhaps the most dramatic grass selected this year is giant needle grass (Stipa gigantea). Evergreen in mild winters, it rises to eight feet in height when its silvery seed heads are produced in summer. The seed heads age to gold by autumn, and the entire plant can be left for off-season interest. Giant needle grass dances in the slightest breeze, adding movement and grace to a sunny location.
Easy, Beautiful, Hardy Geraniums
Given the number of hardy geraniums nominated this year, it is somewhat surprising that only four were selected, but these four are excellent garden plants. All but the first are groundcovers.
Geranium ‘Ann Folkard’ was selected for its eye-catching contrast of chartreuse foliage and magenta flowers. This is an outstanding geranium, blooming from summer to mid-autumn. ‘Ann Folkard’ prefers sun but will tolerate some shade, and grows two feet high by three feet wide.
Geranium himalayense ‘Baby Blue’, a carpet-forming perennial, bears large, violet blue flowers from early summer to early autumn. Used as a groundcover, it is incredibly easy to grow, tolerating a variety of light conditions from full sun to full shade. Geranium x riversleaianum ‘Mavis Simpson’ has silvery blue foliage and, in summer, clear pink flowers. It has a trailing habit, making it ideal for a sunny or semi-shady rockery edge. Geranium ‘Salome’ is another selection used for contrast and groundcover. Its spring foliage emerges yellow and chartreuse and, depending on light conditions, may turn pale green in summer. The large summer flowers are lavender and maroon. ‘Salome’ will tolerate some shade.
The Shade Garden
There are enough shade-tolerant plants on this year’s list to create an entire shade border. The selections range in height from ankle-high cyclamen, perfect for the woodland floor, to the tall, breezy thalictrum, ideal for the back of the border.
Two cyclamen were chosen this year. Cyclamen coum bears shiny, rounded leaves, often with silver markings. They make a perfect foil for the sweet flowers, ranging in color from white to maroon in winter and early spring. Cyclamen hederifolium has a more triangular, ivy-like shape to its leaves, with varying patterns of dark to light green, gray green, or silver. Flowers vary from light to dark pink and appear in late summer through early winter. Plant the two species together for months of delight in a lightly shaded corner.
Another low-growing, shade-tolerant plant is miniature London pride (Saxifraga umbrosa var. primuloides). This evergreen, mat-forming perennial features airy stalks of white flowers whose petals are dotted with red, held above scalloped green leaves. It is useful in rock gardens where it will fill cracks and crevices.
Pulmonaria ‘Benediction’ joins Pulmonaria longifolia subsp. cevennensis, chosen in the first year (2001) of the Great Plant Picks. ‘Benediction’ was selected for its rich blue flowers in early spring and dark green summer foliage with a light variegation.
Hosta ‘June’ is the 2001 American Hosta Growers Association “Hosta of the Year.” It’s no wonder: the heart-shaped leaves are a wonderful combination of blue, gold, chartreuse, and green. It has a good resistance to slugs and quickly forms a sizable clump. Summer flowers on ‘June’ are pale lavender. Like most hostas, she prefers a somewhat shady position in the garden.
Hellebores are increasingly popular in the Northwest garden for their evergreen foliage and low maintenance needs, and because they flower when the rest of the garden is fairly quiet. This year, Great Plant Picks features two selections to compliment last year’s choice of stinking hellebore (Helleborus foetidus). Corsican hellebore (Helleborus argutifolius) bursts with pale green and creamy flowers in late winter to early spring (see Pacific Horticulture, January 2001). Its leathery, evergreen leaves are light green with a distinct platinum sheen. Corsican hellebore prefers full sun but will take some shade. The hybrid Lenten rose (Helleborus hybridus) offers a wide variety of flower color, including white, pink, purple, yellow, rose, and green. Flowers appear from mid-winter to mid-spring. Generally evergreen, this hybrid group is the perfect anchor for the shade border.
Variegation is always welcome in the shade, and variegated water figwort (Scrophularia auriculata ‘Variegata’) makes an ideal foliage plant. The wrinkled, matte green leaves feature bold creamy white margins. This large perennial bears yellowish-green flowers throughout the summer and into early autumn. It prefers some moisture and would be useful in marginally aquatic situations.
For the back of the shade border, consider Thalictrum delavayi ‘Hewitt’s Double’. At four feet high, this meadow rue presents sprays of double pink, pompom-like flowers from mid-summer to early autumn, lending an airy texture to the shady border.
More Best Bulbs
In addition to the two species of cyclamen, the perennial group selected two other bulbs this year. Star of Persia (Allium christophii) was selected for its large purple flower heads that may reach ten inches across in late spring and early summer. The flower heads dry well and can be left on the plant for summer and fall interest.
Crocus tommasinianus is less attractive to wildlife than other crocuses and is a staple of the winter garden. This species varies in color from pale lilac to reddish purple and appears just when we need it the most in late winter and early spring. A dwarf crocus, with flowers no more than three inches tall, it is clump forming and prefers a sunny location.
Flowers to Extend the Season
Several of this year’s perennial Great Plant Picks will flower late in the summer and into autumn. Aster lateriflorus ‘Prince’ was selected for its profusion of small pink flowers (actually white with burgundy centers) in late summer and autumn. In autumn, the foliage turns from the deep purplish-green of summer to plum-purple. ‘Prince’ grows from two to three feet high and has an upright shrubby habit, which makes it useful as a low hedge.
Another late bloomer is Cimicifuga simplex var. simplex ‘Brunette’. Its dark, brownish purple foliage provides a splendid contrast for the yellow or variegated foliage of other selections for the shade garden this year. ‘Brunette’ will grow approximately three feet high and produces long, creamy white, fragrant panicles in autumn.
Euphorbia characias subsp. wulfenii is a large, evergreen, Mediterranean spurge chosen for its bold chartreuse flower heads from late winter to early spring. The purple-tinged foliage provides a striking contrast for the flowers. This species is drought tolerant once established.
The Rest of the Best for 2002
One of the easiest groundcovers to grow, Leptinella squalida ‘Platt’s Black’ creates a furry textured mat between stepping-stones and at the base of perennials and shrubs. Not particular about soil, and drought tolerant once established, this tiny fern-like plant features gray and blackish-purple foliage year-round. Tiny yellow flowers, like brass buttons, are produced in late spring and early summer.
Leucanthemum x superbum ‘Becky’ is a Shasta daisy selected for its large white blooms that do not require staking, for its flowering season from early summer to early autumn, and for its value as a cut flower. Place ‘Becky’ in a sunny position for best performance.
Salvia verticillata ‘Purple Rain’ features tall, branched stems of rich lavender purple floral spires in summer. The leaves are similar to other salvias, softly hairy and gray green. The contrast of flower color to foliage is sumptuous in the middle of a sunny border.
Diggers’ speedwell (Parahebe perfoliata) is an evergreen perennial selected for its bluish-gray foliage and for its terminal spikes of tiny, blue violet flowers in summer. This speedwell prefers some shelter from cold, drying winds, but you’ll find its ability to tolerate a variety of soil and moisture conditions makes it an easy plant to grow.
2002 Great Plant Picks
Perennials and Bulbs
Acorus gramineus ‘Ogon’ (3b-10, 14-24)
Allium christophii (1-24)
Star of Persia
Anemathele lessoniana (14-24)
pheasant’s tail grass (formerly Stipa arundinacea)
Aster lateriflorus ‘Prince’ (1-10, 14-21)
Carex morrowii ‘Ice Dance’ (3-9, 14-24)
Carex elata ‘Aurea’ (2-9, 14-24)
variegated tufted sedge
Cimicifuga simplex var. simplex ‘Brunette’ (1-7, 17)
Crocus tommasinianus (1-24)
Cyclamen coum (2-9, 14-24)
Cyclamen hederifolium (2-9, 14-24)
Diascia vigilis ‘Jack Elliott’ (4-9, 14-24)
Euphorbia characias subsp. wulfenii (4-24)
Geranium ‘Ann Folkard’ (2b-9, 14-24)
Geranium himalayense ‘Baby Blue’ (1-24)
Geranium x riversleaianum ‘Mavis Simpson’ (2b-9, 14-24)
Hakonechloa macra ‘Aureola’ (2-9, 14-24)
golden Japanese forest grass
Helictotrichon sempervirens (1-24)
blue oat grass
Helleborus argutifolius (3b-9, 14-24)
Helleborus hybridus (2b-10, 14-24)
hybrid Lenten rose
Hosta ‘June’ (1-10, 14-21)
Leptinella squalida ‘Platt’s Black’
formerly Cotula ‘Platt’s Black’
Leucanthemum x superbum ‘Becky’ (1-24)
Miscanthus sinensis ‘Morning Light’ (2-24)
Molinia caerulea ‘Variegata’ (1-9, 14-24)
variegated purple moor grass
Parahebe perfoliata (5, 6, 15-17, 20-24)
Pulmonaria ‘Benediction’ (1-9, 14-17)
Salvia verticillata ‘Purple Rain’ (2-10, 14-24)
Saxifraga umbrosa var. primuloides (2-7, 14-17)
miniature London pride
Scrophularia auriculata ‘Variegata’ (3-9, 14-24)
variegated water figwort
Stipa gigantea (4-9, 14-24)
giant needle grass
Thalictrum delavayi ‘Hewitt’s Double’ (2-10, 14-17)
All selections in the Great Plant Picks have been chosen for their suitability in USDA hardiness zones 7 and 8, which covers most of the Pacific Northwest, west of the Cascades. In the list above, zone numbers in parentheses refer to Sunset zones in the latest Sunset Western Garden Book and have been provided for readers beyond the Northwest. Plants may not perform equally well in all of the Sunset zones noted.
To learn more about Great Plant Picks, please visit our website at www.greatplantpicks.org. There you will find photographs, fact sheets, selection criteria, and current evaluation reports. To join our mailing list, please call (206) 363-4803.