Spring blossoms, funky ferns, charming groundcovers, fancy foliage, delicious fragrance, knock-your-socks-off color—the 2005 Great Plant Picks have it all! There are almost one hundred new selections this year, and about half of those are clustered into “small collections,” each represented by only one photograph on our iconic poster. This is an ingenious compromise, we think, between earmarking a comprehensive plant palette for Pacific Northwest gardeners and overwhelming gardeners with too many choices.
So, where to begin? Gardeners love perennial flowers, so let’s start with those. White wood aster (Aster divaricatus) is a shade-loving species native to eastern North America. It has an open habit with wiry, blackish purple stems; it bears small white flower heads in summer. Carl Elliot of Northwest Perennials comments that wood aster provides “a cooling look in summer’s heat. It’s perfect for the woodland garden, skirting shrubs and mixed with ferns. Allow it to spill into other plants or stake it if you are overly tidy.”
Of a similar, airy quality is the curiously named bowman’s root (Gillenia trifoliata). This lovely perennial was introduced into cultivation in 1713, so it is surprising that it is not more widely grown. Graham Stuart Thomas’s description, in Perennial Garden Plants is hard to beat: “A tough, wiry plant whose reddish stems are sparsely leaved, but branch freely into flights of small white flowers. The red calyces persist in beauty after the petals have dropped. Dainty and refined. Almost any position and soil seem to suit it.”
Variegated Dalmatian iris (Iris pallida ‘Argentea Variegata’ and ‘Variegata’) boasts showy flowers of light purple flowers on two-foot stems above striking, brightly striped foliage fans—more white in the former, more yellow in the latter. Unlike many of the bearded irises, the leaves of Dalmatian iris remain presentable throughout the season. These are dependable irises for the mixed border with average garden soil in a sunny or lightly shaded situation.
Epimedium x rubrum (which is rarely asked for by its common name, barrenwort) and creeping forget-me-not (Omphalodes verna) are dainty groundcovers with sweet flowers. In time, both will fill an area and produce a sheet of blossoms in spring—epimedium with soft red flowers, forget-me-not with soft blue. Both do well in shade, making them ideal beneath trees or shrubs. At VanDusen Botanical Garden in Vancouver, BC, the wide-reaching branches of witch hazels (Hamamelis) stretch to cover a sea of blue Omphalodes—quite a sight in March.
A handful of bulbs have made the Great Plant Picks list for 2005. The earliest of these to bloom are the snowdrops (Galanthus), most often flowering in January, but this will vary with the weather. Giant snowdrop (G. elwesii) is the tallest, reaching nine inches. It has broad, bluish leaves that may twist. Galanthus ikariae is one of my personal favorites, with its bright green leaves and smaller stature. Common snowdrop (G. nivalis) is even shorter (six inches) but has glaucous leaves. If they are happy, snowdrops will form large swathes in your garden. The most glorious planting of snowdrops around is at the Dunn Garden in Seattle, where the moss has been allowed to carpet the ground. The composition of acid-green moss, blue gray leaves and white flowers is memorable.
Yellow fawn lily (Erythronium ‘Pagoda’) grows from a corm. It is a hybrid of E. revolutum, also called trout lily, and is more vigorous than the species, easily spreading to form a mass of mottled, glossy, deep green leaves with stems bearing three or four soft yellow flowers each. Soon after flowering in April, the whole plant withers, enabling it to survive our dry summers with little supplemental water.
Narcissus ‘King Alfred’ is one of the most popular of all the yellow trumpet daffodils and was chosen as a Great Plant Pick for its ability to persist in the landscape. After ‘King Alfred’ comes Tulipa ‘Spring Green’, which is one of the “viridiflora” (green-flowered) tulips. Its flowers are stunning: ivory white with emerald green brushstrokes emerging from the base of the flower; they appear in mid- to late season on twenty-inch stems.
A superlative native bulb, variously called quamash, Indian hyacinth, or camas (Camassia quamash), flowers in late May or early June. In Plants of the Pacific Northwest Coast, authors Pojar and MacKinnon quote Meriwether Lewis’s June 1806 journal entry. He wrote, “The quawmash is now in blume…and resembles lakes of fine clear water.” The ensuing spread of agriculture and human habitation has greatly depleted those wild drifts, but it makes a good garden plant, particularly for large or natural gardens. If the soil is moist, it spreads quickly, or it can be naturalized in rough grass.
A tradition of mine is to plant sweet box (Sarcococca confusa) near the door that opens to the shady side of my home. This is because it blooms early in the season (actually late winter) and is exquisitely fragrant. If you tuck it too far afield, you might miss its scent. This evergreen shrub does not mind deep shade and dry soil once established—hence, its success under the eaves on the north side. It is my favorite in this genus because each glossy, dark green leaf has a little wave to it, so the overall effect is richly textural. The tiny white flowers mature into glossy black fruit. Seedlings often appear under the shrub to be potted up and given away. In Vancouver, I once saw a hedge of sweet box under handsome the leaded glass windows of a home’s library. An image of cracking open a window in March, while curled up with a good book, and inhaling a wonderful perfume came to mind—ah, heaven…
Also fragrant and evergreen, Daphne x transatlantica ‘Jim’s Pride’ is nearly always in bloom, bearing small, pink-flushed, white flowers, with the heaviest bloom period in April. It has small leaves and a rounded habit, growing to only about four feet high. Although daphnes have a reputation for being difficult to cultivate, this hybrid is easy. It is always sold, incorrectly, under the name of D. caucasica; what you buy under that name will, in fact, be ‘Jim’s Pride’.
One of the hottest plants to come out of Great Britain in the past few years is a black elder with deep burgundy leaves that retain their color all season. Sambucus nigra ‘Gerda’ (usually sold as Black Beauty) has pink flower clusters, rather than the cream ones of its main competitor, ‘Guincho Purple’. Black elder makes a major statement in the garden, so give it plenty of room to spread and reach skyward.
A Great Plant Pick goes to Berberis thunbergii f. atropurpurea ‘Rose Glow’, a compact, deciduous Japanese barberry. This selection leafs out dark purple, but, as spring turns to summer, the leaves gain a spattering of candy pink, vanilla, and sometimes a little fresh green thrown in for good measure. As Canadian GPP member Christine Allen points out, it is a “poor choice for siting near deciduous trees, as blowing leaves tend to collect on the lower spines and are difficult to extract without bloodshed!” Nevertheless, it is a colorful shrub with a sturdy constitution.
Japanese spicebush (Lindera obtusiloba) is variable in habit: plants are dioecious, and males tend to become trees, whereas females remain more shrubby. They will eventually reach twenty feet high and wide, with low, horizontal branches and broad, three-lobed deciduous leaves. Female trees bear fruit only if a male is present. The trees at the Washington Park Arboretum fruit regularly, but Arthur Lee Jacobson, author of North American Landscape Trees, notes that the fruit is not particularly showy. Spectacular, however, is the autumn color, which lights up a woodland garden. The trees were described by plant hunter Ernest Wilson in the woods of China’s Hupeh Province as “very conspicuous on account of the brilliant colour of the young leaves.”
Surely, every garden must have a spot for at least one cultivar of hinoki cypress (Chamaecyparis obtusa), an evergreen conifer native to Japan. While the species itself reaches one hundred feet tall in the wild, it is extremely variable, even producing mutations that remain the size of a tennis ball. This calls to mind Canada hemlock (Tsuga canadensis), which we rarely see in cultivation, yet dozens of its cultivars find homes in our gardens.
The five GPP cultivars of hinoki cypress demonstrate this variability. ‘Gracilis’ is the tallest growing, maturing at about twenty feet in height and forming a slender column to about three feet wide. Its twisted, deep green branchlets are held on tiered branches, creating an open habit. With thoughtful pruning, taking care to hide cuts within the branchlets and to respect the irregular structure, this small tree can be shaped to accommodate tight quarters.
‘Nana Gracilis’ is intermediate in habit and structure between ‘Gracilis’ and the dwarf ‘Nana’. Most widely grown of the hinoki cypress cultivars, it has glossy, dark green foliage that also twists, creating a sumptuous texture on a tightly conical shrub. It grows to only two feet in ten years, but with time will reach fifteen feet high.
‘Nana’ repeats the theme on a much smaller scale. Branchlets twist more tightly, almost forming little green cups. The entire plant reaches only two feet in height and three feet across. ‘Nana’ is perfect for a rock garden or a handsome container, perhaps with well-behaved companions while it is young.
In general, the Great Plant Picks Selection Committee hesitates to award a GPP to plants for which there is confused nomenclature. With ‘Nana’, ‘Nana Gracilis’ and ‘Gracilis’, this is sometimes the case as the names are so interconnected. For these plants, however, the committee had several thoughts. First of all, all three are wonderful plants. If you were hoping for one and got another, you would still have an outstanding garden shrub.
Secondly, once you realize the difference between these three cultivars, look carefully at nursery plants for the growth habit. Compactness will indicate rate of growth. Finally, these shrubs are amenable to pruning, within reason. If you wanted ‘Nana Gracilis’ and ended up with ‘Gracilis’, for instance, you could keep it to fifteen feet with attentive pruning.
Chamaecyparis obtusa ‘Coralliformis’ grows slowly to six feet tall and four to five feet wide, with contorted branchlets and twisted foliage. ‘Pygmaea’ has a spreading habit, ultimately growing to three feet high and five feet wide. Red brown shoots carry fan-shaped, bright green foliage that takes on bronze hues in cooler winter weather.
A Rainbow of Rhododendrons
In the spotlight for 2005 are thirty-three outstanding hybrid rhododendrons recommended by the GPP Rhododendron Advisory Group. A veritable rainbow of cultivars falls into five color groups: pink, purple, red, yellow and bicolor. We’ll detail those in the April issue of Pacific Horticulture. The full list will be in our 2005 GPP booklet, available at the Northwest Flower & Garden Show, on our website after February 1, 2005, or by mail if you request one by phone (206/362-8612).
2005 Great Plant Picks
Perennials and Bulbs
Aster divaricatus (1-10, 14-21)
white wood aster
Blechnum penna-marina (15-17, 20-24)
alpine water fern
Brunnera macrophylla ‘Jack Frost’ (1-24)
Camassia quamash (1-10, 14-17)
quamash, Indian hyacinth, camas
Carex oshimensis ‘Evergold’
variegated Japanese sedge
Wallich’s wood fern
Epimedium x rubrum (2-9, 14-17)
Erythronium ‘Pagoda’ (1-7, 14-17)
yellow fawn lily
Galanthus elwesii (1-9, 14-17)
Galanthus ikariae (1-9, 14-17)
Galanthus nivalis (1-9, 14-17)
Gentiana asclepiadea (2-6, 14-17)
Iris pallida ‘Argentea Variegata’ Hort. (1-24)
variegated Dalmatian iris
Iris pallida ‘Variegata’ (1-24)
variegated Dalmatian iris
Narcissus ‘King Alfred’ (1-24)
Osmunda regalis and cultivars (1-9, 14-17)
royal fern, regal fern
crested royal fern
purple-tinged royal fern
undulate royal fern
Perovskia atriplicifolia (2-24)
Polystichum munitum (2-9, 14-24)
Smilacina racemosa (1-7, 14-17)
false Solomon’s seal
Tulipa ‘Spring Green’ (1-24)
Shrubs and Vines
Arbutus unedo ‘Compacta’ (4-24)
compact strawberry tree
Berberis thunbergii f. atropurpurea ‘Rose Glow’ (2b-24)
variegated Japanese barberry
Clematis [Alpina Group] ‘Constance’ (2-6, 15-17)
Cornus alba ‘Elegantissima’ (1-9, 14-24)
Cotinus coggygria ‘Royal Purple’ (2-24)
Daphne x transatlantica ‘Jim’s Pride’
Hibiscus syriacus ‘Diana’ (2-24)
Pieris japonica ‘Variegata’ (2b-9, 14-17)
variegated lily-of-the-valley shrub
Sambucus nigra ‘Gerda’ (sold as Black Beauty) (2-7, 14-17)
purpleleaf black elder
Sarcococca confusa (4-9, 14-24)
Vaccinium ovatum (4-7, 14-17, 22-24)
Viburnum plicatum f. tomentosum ‘Mariesii’ (3-9, 14-24)
Trees and Conifers
Abies grandis (1-9, 14-17)
Abies pinsapo (5-11, 14-24)
Cephalotaxus harringtonii (4-9, 14-17)
cowtail pine, plum yew
Chamaecyparis obtusa cultivars (2b-6, 15-17)
dwarf hinoki cypress
dwarf hinoki cypress
dwarf hinoki cypress
dwarf hinoki cypress
dwarf hinoki cypress
Cryptomeria japonica ‘Cristata’ (4-9, 14-24)
crested Japanese cedar
Lindera obtusiloba (3b-6, 14-17)
Liriodendron tulipifera and cultivars (2-12, 14-24)
variegated tulip tree
columnar tulip tree
Nyssa sylvatica (2-10, 14-21)
black gum, sour gum
Thuja occidentalis ‘Smaragd’ (1-9, 15-17, 21-24)
Thujopsis dolabrata (3b-7, 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 (when available) and have been provided as an aid 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) 362-8612.
Great Plant Picks Selection Criteria
All plants should:
- be hardy in USDA zones 7 and 8 (0° to 10° F/ -18° to -12° C).
- be long lived.
- be vigorous and easy to grow by a gardener of average means and experience. (Plants shouldn’t require the knowledge of a specialist.)
- be reasonably disease and pest resistant.
- have a long season or preferably multiple seasons of interest.
- be available from at least two retail sources in Canada and the US.
- be adaptable to a variety of soil and fertility conditions.
- not require excessive moisture (with the exception of aquatic plants).
- not be invasive or overly vigorous in colonizing the garden or the larger environment.
- perennials should not require staking, continuous deadheading, or frequent division.
- trees and shrubs should require little pruning and nominal training to achieve their best form (excluding plants used for hedges).
- bulbs should persist in the garden, without being lifted, for at least three years.
- leaves of variegated plants should be stable and not revert back to a green form.