Following article used by permission of the Hudson Valley Chapter of the North American Rock Garden Society. Copyright © 1992.
These plants are selected for ease of cultivation and availability. That said, most are not tolerant of arbitrary environmental choices; you ignore the cultural suggestions at your plant's peril. Moreover, what is easy in the Northwest is not necessarily easy in the Southeast.
Though we have attempted to counter our Northeast bias with review from around the country, the blame for inappropriate recommendations remains with us. Still, you can read this advice with a view towards adapting it to your own climate. If you are in Seattle and the advice is "part or full sun," choose full sun. If you are in the Rockies with a third of the Northeast's rainfall, figure out how you are going to accommodate woodland plants before you tackle them. If you are in the Piedmont, where summer heat murders alpines, the saving grace may be replacing "full sun" with afternoon shade.
USDA ratings are given for the minimum and maximum Zones where these plants grow well. (If you don't know your Zone, ask your county extension agent.) The high end was chosen to reflect the rigorous heat and humidity of the Southeast. If you are subject to a drier or more moderate climate, you can stretch the upper limits.
No matter what you do, you will have failures; all rock gardeners do. When that happens, look at the brethren of the recently deceased in rock gardens near you. Note the differences in cultural conditions; ask what's under the gravel mulch; ask about the pH factor of the soil; ask about watering. Use the local chapter of the North American Rock Garden Society for access and invitations.
Where do you get these plants? Even in a list like this, chosen for availability, only a smattering will be at your local garden center. Your local chapter of NARGS will have suggestions, and they may even have a plant sale. Check out the 'Links' section located at the top of the NARGS Home Page for a list of nurseries and seed sources.
Acantholimon [ah-kan-tho-ly-mon]. This handsome evergreen perennial, a native of Turkey, does well on sunny slopes, in scree beds, the alpine house, and, sometimes, in the open garden. The needle-like foliage makes a fine background for pink summer flowers, which are followed by papery bracts. The plant makes a compact mat, and will grow comfortably in Zones 6-9, and sometimes even in Zones 3, 4 and 5. The acantholimons grow wild from Greece eastward to Asia and several varieties are well known. A. glumaceum [gloo-mah-see-um], native to Russia, has deep rose pink flowers and is the easiest species to grow.
Achillea ageratifolia [ah-kil-lee-ah a-ge-ra-ti-fo-lee-ah]. (syn. A. serbica). Profuse 1" white daisies in May on 6" stems above a creeping mat of silvery, felted, lance-shaped leaves. Sun, well-drained soil, scree or between paving stones. From mountains in Greece and the Balkans. Zone 3.
Achillea tomentosa [toe-men-toe-sa]. Yellow flowers on 6" stems over downy, wooly, finely cut aromatic foliage. Tough and dependable. Can be mowed. There exists a fine dwarf form 'Aurea'. Full sun, good drainage. Eurasia. Zones 2-8.
Adiantum venustum [a-dee-an-tum ve-new-stum]. A Maidenhair Fern with 6-12" triangular fronds that are brilliant soft green in spring, bluish green when mature. Spreads fairly rapidly; good wall plant. Likes rich, humusy soil, and should not be planted too deeply. Himalayas. Zones 2-8.
Aethionema armenum [eeth-ee-oh-nee-ma ar-mee-num]. Shrublet with gray-blue foliage and spikes of soft pink flowers in late spring. The hybrid cultivar 'Warley Rose' is especially nice, with deep pink flowers. Grows in full sun in well-drained soil. Prolific bloomer. 3-8". Fragrant. Asia Minor. Zones 5-8.
Alchemilla alpina [al-keh-mil-lah al-pie-nah]. Foliage is green on top, silvery underneath, and more attractive than the short sprays of green-tinged flowers in spring. Sun or partial shade, in well-drained but moisture-retentive soil. Good wall plant. 6-8" high. Europe. Zones 3-7. A. saxatilis [sachs-a-til-lis] is similar and even easier.
Alyssum saxatile [ah-lis-sum sachs-sah-ta-lee]. (syn. Aurinia saxatilis). Basket of Gold. Clouds of tiny yellow flowers in May, very floriferous. Up to 6" with strap-shaped silvery foliage but can spread to 2'. The cultivar 'Citrinum' is pale yellow and combines better with other spring flower colors. Europe. Zones 2-7.
Allium thunbergii 'Ozawa' [al-ee-um thun-ber-jee-eye]. Strap-like leaves, bright rosy purple flowers on 8-12" stems. Likes moist, well-drained soil and half-day of sun. Late-blooming treasure from Japan. Zones 2-8.
Anacyclus pyrethrum var. depressus [an-ah-cy-klus pie-ree-thrum de-press-us]. (Commonly known simply as A. depressus). Mt. Atlas Daisy, 3-6", grows in a well-drained sunny location. White daisy-like flowers, with red underside, in May-June, so it opens white and closes red over gray-green filigree foliage. Morocco. Zones 3-8.
Androsace lanuginosa [an-dross-ah-see lah-noo-gi-noh-sa]. A summer-flowering trailing species, with wooly leaves and umbels of pale pink flowers. 3-4". Likes a light sandy soil and afternoon shade in the Southeast. Himalayas. Zones 3-8.
Androsace sarmentosa [sar-men-toe-sah]. Perennial rosettes, slightly hairy leaves. Umbels of pink flowers with yellow eyes in late spring. Sun or partial shade. Limy scree. 4-6" high, slowly spreads via strawberry-like runners to 2'. The overwintering form has tight, small rosettes. The variety 'Chumbyi' is densely tufted and hairy. Himalayas. Zones 2-8.
Anemone nemorosa [ah-nem-oh-nee nem-oh-roh-sa]. European Wood Anemone. A few inches high. Many colored formswhite, red, lavender, and blue. Deeply cut leaves. A fine spring ephemeral for the woodland. Place in an undisturbed location as it goes dormant at the end of June. It may take two or three years to establish, but will spread rapidly if well-sited. Zones 3-8.
Anemone sylvestris [sill-vess-tris]. Clump-forming perennial, with tufts of dark leaves. Fragrant, nodding 2" white flowers in late spring. Grows in partial shade in humus-rich conditions. 6-15" high. Eurasia. Zones 2-7.
Anemonella thalictroides [ah-nem-oh-nell-ah tha-lick-troy-i-dees]. Tuberous-rooted perennial with delicate 3-lobed leaflets. Single, white flowers. Double forms and pink-flowered forms also exist. A favorite Northeastern woodland native. Humus-rich soil. 4-10" high. Zones 3-8.
Antennaria dioica [an-ten-nay-ree-ah dye-oh-ee-ka]. Pussytoes is a mat-forming perennial with wooly, gray leaves, white underneath and bears heads of gray everlasting flowers in mid-spring. Full sun, no competition and dry, lean soil. There are forms with pink or reddish coloring. 2-4" high. Circumpolar. Zones 2-8.
Aquilegia bertolonii [a-kwi-lee-jee-ah ber-toe-low-nee-eye]. One of the best of the columbines for the rock garden. Dark green leaves. Large, rich purple flowers in May with incurved spurs on 3" stems. Woodland or cool scree. Southern Europe. Zones 3-8.
Aquilegia canadensis [kan-uh-den-sis]. A 1-2' columbine. Spring flowers, with scarlet sepals and yellow petals ending in scarlet spurs. Sun or half shade. Cultivar 'Nana' is better proportioned for the rock garden. Nova Scotia to Florida, west to Minnesota. Zones 2-8.
Aquilegia flabellata [fla-bell-lah-tah]. Short-spurred blue and white flowers on 8-10" stems in early summer. Light green glaucous foliage. There are dwarf ('Nana', 3") and larger white-flowering ('Alba') cultivars. Japan. Zones 2-9.
Arabis caucasica [ar-ah-biss kaw-kah-si-ka]. 8-14", white fragrant flowers on loose racemes in early spring. There is a magenta and a double white form. Caucasus. Zones 3-8.
Arabis procurrens [pro-cur-rens]. (Material in cultivation is often called Arabis ferdinandi-coburgii). Gray leaves. White flowers on 5" stems in spring. There is a preferred selection 'Variegata' which does best in bright shade. Bulgaria. Zones 3-8.
Arabis x sturii [times stur-ee-eye]. Neat dark green tufts of small pointed glossy leaves. Large white flowers on 3-4" stems in spring. Sun. Sparser in bloom but better in foliage than most species. Southern Europe. Zones 3-8.
Arenaria montana [a-ren-air-ee-ah mon-tan-ah]. Large white flowers in June on long trailing stems with narrow lance-shaped leaves. Forms low mounds. Sun. A rather fast grower which can spread 2' in one season. Alps. Zones 3-8.
Armeria juniperifolia [ar-mer-ee-ah ju-nip-er-i-fo-lee-ah]. (syn. A. caespitosa). Dense evergreen cushions of short rigid stems, 2" high, covered with large pink, ball-shaped flower heads. Light, well-drained soil. Good for troughs. Spain. Zones 3-8.
Armeria maritima [ma-ri-tee-mah]. Very variable in color, from white to rose, the usual form is lilac pink. Tiny flowers in rounded heads in late May. Forms a dark green grass-like mat. Brightest selection is cherry-red 'Düsseldorf Pride'. Greenland, Europe. Zones 3-8.
Asarum europaeum [ah-sah-rum you-row-peh-um]. European Ginger is an excellent, evergreen ground cover for smaller, refined areas. It likes humusy soil in part or full shade. It is approximately 4" high with shiny, kidney-shaped leaves. Zones 4-7.
Asplenium trichomanes [ah-splee-nee-um try-koh-mah-nees]. Maidenhair Spleenwort. Evergreen hardy rock fern, slender fronds 4-6" long, 3/4" wide in neat rosettes. Likes well-drained, moist, limy loam, some sun. Good wall or woodland plant. Eastern North America. Zones 3-8.
Aster alpinus [ass-ter al-pie-nus]. This is a European high alpine, perennial aster having elliptical, hairy leaves with large solitary violet flowers on 10" stems in mid-spring. It grows easily in rocky soil in full sun. It may need protection from slugs, at least when young. There are many selected forms. Zones 3-7.
Astilbe chinensis 'Pumila' [ah-still-bee chi-nen-sis pooh-mi-lah]. This member of the Saxifrage family has heavily "cut" foliage. It does best in rocky, moist areas, but is more drought-tolerant than other astilbes. Rosy lavender 8" spikes flower in August. Spreads rapidly by rhizomes, but easily controlled. Zones 2-8.
Astilbe simplicifolia [sim-pli-si-fo-lee-ah]. Perennial plant with white flower spikes in July-August. 8-10" tall. 'Rosea' is smaller with rich pink flowers. 'William Buchanan' has reddish leaves with cream flowers. Likes rich loam with moisture; does well in part or full shade. Japan. Zones 2-8.
Athyrium niponicum 'Pictum' [ah-thi-ree-um ni-pon-eh-kum pik-tum]. Japanese Painted Fern. Deciduous with fronds 8-12" long of a soft gray-green, whitish in the center with wine-red stems. The lovely colorings show best in partial shade. Moist, humus-rich soil. The fronds emerge in late May. Zones 5-8.
Aubrieta deltoides [oh-bree-ay-tah del-toe-i-dees]. Rockcress. A fairly easy, prostrate mat-forming perennial with pink or purple flowers, 6" high trailing to 2'. A classic rockery plant, it looks best dropping over a wall and often does best in an east-facing exposure. It should be pruned back after blooming to keep it compact and to avoid seeding. From stony, limy rockslides of the Mediterranean. Zones 3-8.
Callirhoe involucrata [kah-lee-row-ee in-vol-you-kray-tah]. Poppy Mallow or Winecups. It grows to 8" high with a spread of 16-24". Best grown from seed, it develops tremendous roots and looks better dropping over a wall. Blooms constantly through July and August with large magenta, cup-like flowers. Great Plains. Zones 3-8.
Campanula carpatica [kam-pan-you-lah car-pah-ti-kah]. Carpathian Harebell. One of the best known of the campanulas, it produces large white or blue saucer-shaped flowers over a long period in summer. 8-12". Sun or semi-shade in a well-drained soil, mixed with manure or compost. Slugs are a problem in the Northwest. Carpathians. Zones 2-8.
Campanula garganica [gar-gah-ni-kah]. 2-3" with toothed, rounded, heart-shaped leaves and many small starry blue flowers with white eyes. Considered a showy variety. One of the best and easiest. Flowers June-July. Italy. Zones 2-8.
Campanula portenschlagiana [por-ten-schlahg-ee-ah-nah]. (syn. C. muralis). This plant is an easy grower, 4-8" , with long-lasting, purple-blue flowers, spreading among rocks in a wall. Flowers in early summer and early autumn. Yugoslavia. Zones 2-8.
Chrysogonum virginianum [kri-sog-on-um vir-gin-ee-ay-num]. This is a useful hardy herbaceous ground cover for sun or light shade producing yellow daisy flowers, 1-2" in diameter, May to October. It is a native of the eastern U.S. Plant in a dry, well-drained peaty soil. Grows easily in Zones 5-9.
Claytonia virginica [klay-tone-ee-ah vir-gi-ni-kah]. Spring Beauty. One of our best eastern wild flowers with pink-striped white flowers in very early spring. It requires moist rich soil in shade. It comes on early, but vanishes just as early, before the start of summer. Zones 3-8.
Crocus speciosus [krow-kus spee-see-oh-sus]. An autumn-flowering member of the genus, the closest to blue. The cultivar 'Cassiope' is large, late and very blue. Sun or shade. The foliage emerges in early spring. Iran, Turkey, Russia. There are many fine species of crocus for both spring and fall. Zones 3-9.
Cyclamen hederifolium [sick-lah-men head-er-eh-fo-lee-um]. (syn. C. neapolitanum). This striking plant comes from southern Europe and eastern Asia Minor. The leaves are heart-shaped with highly variable silver markings. Flowers vary from white to rose, blooming in the autumn. The leaves disappear in spring and reemerge when flowering commences. Another species, C. coum has a rounder leaf and is late-winter-blooming. The foliage emerges with the flowers and dies back in mid-summer. Both require woodland shade and mulch north of Zone 6. Zones 4-9.
Delosperma nubigenum [dell-oh-sper-mah new-bi-jee-num]. Ice Plant. Wide-spreading, inch-high mats of yellow-green succulent foliage that turns red in cold weather. Dazzling spring display of bright yellow flowers. Hardy in a well-drained soil or scree. From the mountains of southeastern Africa. Zones 3-8.
Dianthus alpinus [dye-an-thus al-pie-nus]. A mat-forming plant, with a spread of 8-10". Deep green, almost lush, strap-shaped leaves with large (1" or more), attractive, late spring flowers varying from deep rose to white. The plant prefers a light, well-drained limy soil in sun or light shade. Slugs are a problem in the Northwest. Switzerland to Russia. Zones 3-8.
Dianthus deltoides [dell-toe-i-dees]. Up to 9" in height with a spread of 16-20", this species has long grassy, linear blue-green leaves with charming fringed deep pink flowers. Blooms mid-summer, when most other rock plant flowers are scarce, with a succession of bloom all summer. In dry soil, it is sometimes tinged with bronze coloration. It can become invasive. Eurasia. Zones 2-9.
Dianthus gratianopolitanus [grah-tee-ah-no-po-li-tay-nus]. (Formerly D. caesius). Cheddar Pink. Very fragrant rose-pink flowers. Excellent in dry areas. 6-8". June. Evergreen ground cover. The cultivar 'Tiny Rubies' is a choice, scaled-down selection with double pink flowers. Europe. Zones 3-9.
Dicentra eximia [dye-sen-trah eks-i-mee-ah]. Fringed Bleeding Heart. Handsome, gray-green, lacy foliage with 12" sprays of deep rose-pink, heart-shaped flowers from spring through summer. Freely speads around the garden, but is easily transplanted to more desirable sites. Partial shade to full sun. Rich, moist soil. Appalachians. Zones 2-9.
Dodecatheon meadia [doh-de-ka-thee-on mee-dee-ah]. Shooting Star. Prefers cool, shaded sites. Grows to a height of 14". It has broad, oblong leaves of soft, attractive green and, during late spring, umbels of magenta or white cyclamen-like flowers with yellow anthers. It goes dormant in summer. Eastern North America. Zones 2-8.
Draba aizoides [drah-bah aye-zoh-i-dees]. Whitlow Grass. An evergreen, mat-forming perennial, it makes densely packed cushions producing small yellow crucifer flowers in early spring. Spreads slowly as a bun and the seeds never create a problem. Southern Europe. Zones 2-7.
Dryas octopetala [dry-ass awk-toe-pet-ah-lah]. Generally, it is a splendid and good-tempered rock plant with white, eight-petalled 1" flowers in early summer. Fluffy seed heads are decorative. 3-4" high, it forms dense mats of scalloped, evergreen oak-like leaves. Grow in sandy scree, in sun, with good air circulation. Circumpolar. Zones 1-6.
Epimedium x youngianum 'Niveum' [ep-eh-mee-dee-um times yung-ee-aye-num nih-vee-um]. 6" high foliage with pure white flowers on 8" stems in May. Shady rock garden or woodland with well-drained humus-rich soil. Maximize the show of flowers by cutting down the overwintering foliage. Japan. All epimediums are desirable. Zones 2-8.
Eranthis hyemalis [eh-ran-thus hy-eh-mah-liss]. Winter Aconite. At 4", the first buttercup. If you work at it, you can find strains that will bloom from dead winter to early spring in shady, undisturbed sites. Purchased tubers seldom are viable; beg some from a friend. Europe. Zones 3-7.
Erinus alpinus [eh-rye-nus al-pie-nus]. Hardy, low, tufted evergreen perennial mat 3" x 3". Rosy purple flowers are in racemes on 4" stems in June. Partial shade, well-drained gritty soil or protected crevice. There are also good white and pink forms. Native of the rocks, screes and stony grassland in the Pyrenees, Alps, and central Apennines. Zones 4-8.
Eriogonum umbellatum [air-ee-awe-gon-um um-bell-ay-tum]. Sulphur Flower, Umbrella Plant. Natives of western North America, the eriogonums thrive in well-drained soil and sunny spaces. Yellow flowers on 6-12" stems blooming from June to August arch over a slow-spreading mat of silvery green leaves. In high rainfall areas it should be grown in scree. Rocky Mountains. Zones 2-7.
Erysimum kotschyanum [eh-rih-sih-mum kot-chee-aye-num]. (Material in commerce is probably E. helveticum). A 3" tufted perennial mat of small toothed leaves. 3-4" stems carry orange-yellow flowers in spring. Can expand rapidly but can be controlled. Full sun, gritty well-drained soil or tight rock crevice or trough. Native of the high mountains in Asia Minor. Zones 3-8.
Euphorbia myrsinites [you-for-bee-ah mur-sin-eye-tees]. Bluish green fleshy leaves on sprawling stems which ascend at their ends to 8". Yellow flowers in umbels in spring. Sunny or partly shady warm exposure trailing on or over rocks. Trim back flowering stems unless seeds are desired. Native to rocky and grassy places in the eastern Mediterranean. Zones 3-9. NOTE: in CO and WA, this plant is classed as a noxious weed. See the USDA plant list.
Gentiana scabra [jen-shee-ah-nah skay-brah]. Narrow ovate leaves on 12" plant. The dark blue flowers are in clusters at the stem tops and in the upper leaf axils in October. Sun. Moist humus-rich, well-drained soil with cool exposure. Native to eastern Asia and Japan. Zones 5-8.
Gentiana septemfida var. lagodechiana [sep-tem-fye-dah lah-goh-dee-kee-ah-nah]. Ovate leaves on 10" high perennial. Blue bell-shaped and fringed flowers are in terminal clusters in summer. Sun or part shade. Native to alpine fields of Caucasus up to 9,000 feet, moist but well-drained peaty loam soil. Slugs are a problem in the Northwest. Zones 2-8.
Geranium cinereum [jeh-ray-nee-um sih-ner-ee-um]. Tufted per-ennial 5" high with gray-green deeply toothed, lobed basal leaves. The cultivar 'Ballerina' has lilac-pink flowers veined a darker color in center. G. c. var. subcaulescens 'Splendens' has spectacular cerise dark-eyed flowers. Summer-blooming in good soil and full sun. Species is native to grassy or rocky places in western and central Pyrenees. Zones 2-9.
Geranium dalmaticum [dahl-mah-teh-kum]. Mat-forming rhizomes with 6" stems of small glossy, lobed leaves. 1" wide delicate shell-pink flowers open in June. Sun. Limy, fertile soil. Scarlet fall color. Good wall plant. Balkan Peninsula. Zones 2-8.
Geranium sanguineum var. lancastriense [san-gwin-ee-um lan-kass-tree-en-se]. Dwarf cushion form of species 6" x 18" with soft pink flowers etched with darker veins. Late spring, but blooms off and on all summer. Sun to part shade, rock garden soil. Species is native to dry, rocky or sandy places and open woods throughout Europe. Zones 2-8.
Globularia cordifolia [glob-you-lah-ree-ah kor-deh-foe-lee-ah]. Prostrate creeping subshrub 4" high. Evergreen leaves form 12" mat. 1/2" gray-blue powder-puff heads on 2" stems in summer. Full sun to part shade, scree on warm slope. Native to rocks and screes in eastern Pyrenees, High Alps, and Apennines. Zones 3-8.
Gypsophila repens [jip-sof-eh-lah ree-penz]. Prostrate spreading perennial mat 18" wide with bluish green linear leaves. Masses of small white flowers on 6" stems in late spring and summer. Full sun or part shade. Drought-tolerant. Native to rocky, stony and grassy places and banks in the Alps, Pyrenees and Apennines. Cultivar 'Rosea' has single pink flowers in May. Zones 3-8.
Helianthemum nummularium [hee-lee-an-theh-mum newm-you-lah-ree-um]. Prostrate evergreen subshrub 4" x 12" at maturity. 1" yellow, orange, pink, or white flowers in late May. Native of dry meadows and rocky limestone places throughout Great Britain and southern Europe. Sunny scree conditions. Zones 3-8.
Hepatica americana [heh-pat-i-kah ah-mehr-ih-kah-na]. 1/2" flowers on 5" stems in early spring over semi-evergreen basal leaves with rounded lobes. Colors range from lilac, blue, pink to white. Well-drained soil under layer of leaves in deciduous shade. Native to eastern U.S. and Canada on wooded, slightly acid slopes. Zones 2-8.
Hosta venusta [hoss-tah veh-new-stah]. Perennial. Attractive small plant 3-8" tall, with ribbed leaves and erect stems, bearing 2 or 3 clusters of mauve lily-like flowers. Likes sun with moist soil, or dry shade. Easy from seed or division. From Yakushima, Japan. Zones 2-9.
Houstonia caerulea [you-stone-ee-ah sehr-roo-lee-ah]. (Correctly, but rarely, Hedyotis caerulea). Creeping, semi-evergreen perennial tufts with 1/2" long leaves. 3" stems carry blue or bluish white flowers with a yellow eye in spring. Shady spot, humus-rich, moist soil during summer, but not wet in winter. Native from Nova Scotia to Georgia and Missouri. Zones 3-8. H. serpyllifolia is easier in the Southeast, also requiring a moist, acid soil.
Hutchinsia alpina [hut-chin-see-ah al-pie-nah]. Tufted perennial mat 4" high with lacy, dark green basal leaves 1" long. Heads of pure white flowers in late spring; long-flowering. Needs moist soil on cool bank. Native to limestone rocks and screes of Pyrenees, Alps, northern and central Apennines. Zones 3-7.
Iberis sempervirens [eye-bear-iss sem-per-vye-rens]. Dark evergreen leaves. White flowers are in flat terminal clusters at a height of 10" in spring. The cultivar 'Little Gem' is only 6" high and has larger flowers. Alps from Pyrenees to Asia Minor. Zones 3-8.
Iris cristata [eye-riss kris-tah-tah]. Rhizomatous, 6" foliage. Blue flowers with yellow crest on short stems in late May. Spreads when in light soil. Full sun or part shade, well-drained, moist woodland garden. Native to the southeastern U.S. There is also a pure white form. Slugs love it in the Northwest. Zones 3-9.
Iris pumila [pooh-meh-lah]. 8" sword-like leaves. Solitary flowers like a tiny bearded iris on 3" high stems ranging from yellow to pink and purple in early May. Many named hybrids. Native from Austria to Russia and Asia Minor. In full sun. Zones 2-8.
Iris reticulata [reh-tick-you-lah-tah]. The earliest blooming bulbous iris (about when you have your third night without frost); ranging from almost white through blue to purple 2" flowers on 3" stalks. Full sun, good drainage. Leaves elongate to 15" before going dormant in late May. Caucasus. Zones 2-9.
Lewisia columbiana var. rupicola [lew-iss-ee-ah kohl-um-bee-aye-nah roo-pick-oh-lah]. Loose clusters of magenta flowers on 6" stems cover tufts of narrow fleshy evergreen leaves from May to July. Rich, gritty, well-drained soil, preferably on a slope or rock crevice with a summer dry period. Tiny and good in troughs. From the Cascade and Olympic Mts. Zones 4-7.
Lewisia cotyledon [ko-tih-lee-don]. Clusters of 1" flowers in pastel shades rise on 12" stems over a rosette of strap-like, evergreen leaves which are sometimes edged in electric pink. Gritty lime-free soil over a rich loam, in a cool well-drained spot facing north or east. From the mountains of southern Oregon and northern California. Zones 3-7.
Lilium pumilum [lih-lee-um pooh-mill-um]. Attractive small lily with grassy leaves and small bright scarlet or orange turk's cap flowers. 12-15" tall. Likes well-drained leafy soil and some sun. Protect from drought. China. Zones 3-7.
Linum flavum [lye-num flah-vum]. Clusters of yellow flowers are carried throughout summer on woody stems of 12-16". 'Compactum' is a somewhat smaller form. Any good well-drained soil in full sun to part shade will satisfy this native of central and southern Europe. Zones 2-8.
Linum perenne 'Saphir' [peh-ren-ee sah-feer]. Expect loose multi-branched heads of brilliant blue 1-1/2" flowers throughout summer, 8-10" above a tuft of leafy stems. Excellent when combined with L. flavum. A selected form of a species found on prairies of North America from Texas to Alaska, it will thrive in any good garden soil. Zones 2-9.
Narcissus asturiensis [nar-siss-us ass-tur-ee-en-siss]. (syn. N. minimus). The first and the smallest trumpet, 4" in bloom, deep yellow throughout, a perfect miniature of 'King Alfred'. Full sun and good drainage. A summer baking is appreciated. Mountains of northern Spain. Zones 5-9. There are many fine species, but some are still wild-collected; insist on cultivated material.
Papaver alpinum [pah-pah-ver al-pie-num]. The Alpine Poppy graces the early summer garden with solitary 1-1/2" flowers of white, yellow, red, orange and pink on 8" stems of fine silvery foliage. Requires gravelly, moist soil and a mulch of stone chips. Short-lived but self-sows. Native to the high mountains of the Old World. Zones 3-7.
Penstemon cardwellii 'Roseus' [pen-steh-mon card-well-ee-eye]. Large tubular rose-pink flowers on an 8" spike above dark, finely cut evergreen leaves. Provide a rocky north-facing site with gritty soil and this native of moderate elevations in the Cascade and Coast ranges of Oregon will flower in late spring. Zones 4-8.
Penstemon hirsutus 'Pygmaeus' [her-soo-tus pig-may-us]. From June to August violet-blue 1" long tubular flowers with white lip cover the upper part of 6" wooly spikes of lance-shaped, purplish leaves. From Tennessee to Virginia and north into Canada. Zones 2-8.
Penstemon pinifolius [pin-eh-foh-lee-us]. Scarlet trumpets throughout the summer crown a 6" bush of needle-like, evergreen foliage. Well-drained, lean, gravelly soil in full sun is required for this southwestern U.S. native. Zones 3-8.
Petrorhagia saxifraga [pet-row-ray-jee-ah saks-if-rah-gah]. (syn. Tunica saxifraga). Small pink flowers in masses cover this 8" spreading mound in summer. Well-drained rock garden soil in full sun satisfies this European native. Zone 3.
Phlox divaricata [floks dye-veh-rih-kah-tah]. Wild Blue Phlox bears clusters of fragrant 1-1/2" light blue to lavender or white flowers from April to June. Enjoys rich garden soil in full sun to part shade. Slugs in the Northwest love it. Native from Louisiana to Canada. Zones 2-9.
Phlox 'Millstream Jupiter'. Good blue-violet flowers and long-needled foliage mark this hybrid of P. subulata and P. bifida from Linc Foster's Millstream garden. Best in full sun at the front of the border or spreading over rocks. Zones 3-8.
Phlox stolonifera [stoh-lon-if-er-ah]. Blue, purple, pink or white flowers appear in April-May on an 8" creeping plant. Takes any good garden soil rich in humus in full to light shade. Does not like competition. Native from northern Georgia into Pennsylvania. Zones 2-8.
Phlox subulata 'Schneewittchen' [sub-you-lah-tah shnay-vit-chen]. It sports enchanting-but-small snow-white flowers on a 3" mound of needled foliage. Excellent performer in full sun to part shade in good garden soil. Looks wonderful creeping around rocks or in a wall. Zones 2-8.
Polemonium reptans [poh-leh-moh-nee-um rep-tans]. This version of Jacob's Ladder has clusters of light blue, bell-shaped flowers on 12-18" stems over delicate compound leaves in spring. Provide rich woodland soil in light to moderate shade. While safe in its native area east of the Mississippi, it is fodder for slugs in the Northwest. Zones 2-8.
Polystichum tsus-sinense [pol-lih-stik-um sue-seh-nen-see]. Holly Fern. Evergreen 6-12" triangular fronds with distinctive black veins and holly-like tips. Small neat growth. Likes well-drained loam and takes morning or late afternoon sun. Japan and China. Zones 6-9.
Potentilla neumanniana 'Orange Flame' [poh-ten-till-ah new-man-ee-ah-nah]. (syn. Potentilla verna nana 'Orange Flame'). Numerous coin-like bright yellow flowers in summer on very short stems over dark green dwarf mounds of triangular leaves. Accepting of most soils in full sun. This cultivar forms clumps rather than spreading. Zones 2-8.
Potentilla tridentata [try-den-tah-tah]. Glossy dark green 3-part, 3-toothed leaves turn red in autumn. Clusters of dainty white flowers on 6-8" stems appear in late spring and summer. Rocky or sandy soil in full to part sun. From Canada south across the Midwest to the Atlantic and down into the mountains of Georgia. Zones 2-8. P. alba, though harder to find, is similar but longer blooming.
Primula japonica [prim-you-lah jah-pon-eh-ka]. This primrose, from Japan, is the "queen of the candelabras," with several named forms in white, pink and red shades. It should have part or full sun and damp soil. The flower stems, which appear in late May and June, have successive whorls of flowers, eventually reaching a height of 2'. It will benefit from an annual feeding with manure and bone meal when the plants go dormant in the fall. Zones 3-7.
Primula x juliana [times joo-lee-ah-nah]. (properly, P. x pruhoniciana). These hybrids are small plants with dark green, crinkly foliage and good-sized flowers. The small distinctive red-petioled leaf of P. juliae, one of the parents, is frequently retained in the hybrids. They need rich, well-drained soil in light shade. The best-known hybrid is 'Wanda', a floriferous variety with deep wine-red flowers in April. Zones 4-8.
Primula x polyantha [pol-lee-anth-ah]. This familiar garden primrose is the result of crossing P. veris, P. elatior and P. vulgaris. It forms large clumps about 10" high in April and May. The huge flowers are borne in large flat clusters on stems 8-15" high. Colors include all shades of yellow, red, pink, purple, blue, buff, and bronze. It wants a rich, deep soil, preferably on a slope or raised bed to provide essential drainage to the crown. Zones 3-8.
Primula sieboldii [see-bohl-dee-eye]. A Japanese woodlander and one of the easiest of the primroses. It spreads in mats of light green crinkly leaves about 3" high, that go dormant in mid-summer. The open umbels of up to ten flowers on 8-10" stalks appear in late spring. The individual flowers, frilled at the edges and often snow-flake-like, are in shades of dark pink to white. In any reasonably good soil in deep or light shade or part sun the rhizomes increase in size year after year just beneath the surface. Zones 3-8.
Primula vulgaris [vul-gahr-is]. The wild primrose of English hedge-rows and European mountains forms tuffets of rough dark green leaves with dark-eyed, pale yellow flowers, each on its own stalk carried just above the foliage. There are subspecies ingwerseniana with white flowers from Mt. Olympus in Greece, and ssp. sibthorpii with pale pink blooms from the Balkans. This primula also likes a rich well-drained soil in semi-shade. Zones 2-8.
Pulmonaria longifolia x saccharata [pull-moe-nah-ree-ah lon-jeh-fo-lee-ah times sa-kahr-ah-tah]. P. saccharata is the common Bethlehem Sage or Spotted Dog. The hybrid selection 'Roy Davidson' has long, dark green, narrow spotted leaves with pink flowers aging to blue in plants 1' x 1'. The small bell-like flowers make it one of the most useful plants for partially shaded gardens. All the lungworts revel in rich moist soil in either sun or shade. Zones 2-8.
Pulsatilla vulgaris [puhl-sah-till-ah vuhl-gah-ris]. (syn. Anemone pulsatilla). P. v. is from the lower reaches of the European Alps. It has finely cut leaves, grows 10" high and bears large purplish flowers in April and May, followed by ornamental, fuzzy seed heads. It should be planted in well-drained, limy soil of low fertility in a sunny or slightly shaded place. There are several good color forms ranging from white through lilac to stop light red. Anemone patens from northern Europe, northern Asia and North America from Illinois to Alaska is similar. Zones 2-8.
Sanguinaria canadensis [san-gwi-nah-ree-ah kan-ah-den-sis]. Bloodroot grows wild in eastern North American woodlands. It has thick red-flushed tuberous roots, bleeds orange liquid when cut, and sits very close to the soil surface. In April and May light petaled white flowers appear briefly on stems about 6" high clasped in the tight folds of an unfurled leaf. The double form 'Multiplex' flowers for a longer period. Grows easily in shade in a woodsy soil (pH 5-8), either limy or slightly acid. Zones 2-9.
Saponaria ocymoides [sa-poh-nar-ee-ah oh-sih-moy-i-dees]. This is an easy sprawly rock soapwort in the Pink family. Best grown in ordinary garden soil in full sun where it can drape a bank or large stone wall. It forms tumbling evergreen mounds about 6" high and 2' across and covers itself with bright pink flowers from May to June. It should be cut back severely after flowering to keep it compact. A more desirable form for the rock garden is 'Rubra Compacta'. Alps. Zones 2-8.
Saxifraga cotyledon [saks-if-rah-gah kow-tih-lee-don]. An encrusted saxifrage; it occurs in the mountains of Europe and has rosettes about 8" across of tongue-shaped leaves, beaded but not toothed. In May or June the tall panicles of white flowers, branched and pyramidal in outline, may, when well grown, reach 2' To produce flowers it sometimes is necessary to remove and save for propagation all side rosettes. The flowering rosette dies after blooming. S. cotyledon is one of the most beautiful of the silver saxifrages and one of the easiest to grow. Zones 3-7.
Saxifraga moschata 'Peter Pan' [mos-kah-tah]. This small low-growing mossy saxifrage with scalloped leaves makes a pad of dark green rosettes from which rise vivid crimson flowers in spring. Mossy saxifrages need a cool semi-shaded site, with rich, well-drained soil that does not parch in summer. An annual top dressing of equal parts of coarse sand and leaf mold worked into the carpet of foliage will encourage new roots. Their one common weakness is to die out in patches, especially during hot, muggy weather. Zones 4-6.
Saxifraga paniculata [pah-nik-you-lah-tah]. (syn. S. aizoon). An encrusted saxifrage occurring in Europe and North America. The rosettes, usually 2" across, are composed of narrow spoon-shaped leaves edged with forward-pointing teeth and rimmed with silvery white encrustations and white flowers, spotted with red or purple, on stems about 12" high, flowering in May. Leaf colors range from pale green to silver and silver-blue. The flowers vary from pure white in 'Alba', to yellow in 'Lutea', and bright pink in 'Rosea'. They look best in crevices and do best with shade part of the day. The flowering rosettes die, but are replaced by side rosettes. Zones 2-6.
Scabiosa lucida [skab-ee-oh-sah loo-see-dah]. One of the smaller, dwarf species of scabious, S. lucida has cut leaves and big pincushion flowers of rosy lilac on plants 7" x 8", flowering in summer and continuing into fall. It is from the European mountains. An easy small perennial that reseeds nicely. Grow in either sun or part shade. Zones 4-8.
Scilla tubergeniana [sill-ah too-ber-jin-ee-ah-nah]. (Correct name is S. mischtschenkoana, seldom used, for an obvious reason). Very early 4" spikes of light blue stars with a darker stripe down the center of each petal, elongating and creating a very long bloom period. Grows well in light shade, dry woodland. Iran. Zones 3-9.
Sedum kamtschaticum [see-dum kamt-cha-ti-kum]. A clump-forming stonecrop from Siberia, Manchuria and east Asia, growing up to 9" with large toothed leaves sometimes edged with white. Large clusters of bright yellow stars in July and August. The old stems die back in the fall, but new ones appear from the center of the clump and remain green all winter. After the flowers fade on all varieties, the seed pods turn red and remain attractive. Easy with good drainage. Zones 2-8.
Sedum pluricaule [plur-eh-kawl-eh]. This handsome stonecrop from Sakhalin has round blue leaves and red stems and red flowers. It grows in a slowly spreading clump 2" x 4". 'Rose Carpet' is a good selection. Small sedums in variety have unusual textures and colors and require very little care. Not every pretty plant is difficult. Zones 3-8.
Sedum sieboldii [see-bold-ee-eye]. From August to September, flat heads of pink flowers on 8" stems rise over mounds of succulent, gray-blue round leaves. The foliage remains well into winter. Grows in sun or shade. Japan. Zones 2-9.
Sedum spurium [spur-ee-um]. Mat-forming plant, makes a fine ground cover. Mid-July to August, 6" stems hold clusters of 1/2" pink flowers; the foliage may take on a reddish tinge. 'Dragon's Blood' is a popular selection. Caucasus. Zones 2-8.
Sempervivum arachnoideum [sem-per-vye-vum ah-rack-noy-dee-um]. Low mat-forming succulent with cobweb-like threads covering the foliage. Bright red flowers are borne on 4" stems. Compact rosettes which will grow well in screes, crevices and between paving stones. In dry climates it prefers heavier soils and moisture. Mountains of Europe. Zones 2-8.
Silene alpestris [sy-lee-nee al-pess-tris]. The silenes are a large genus of the Pink family. White snowflake flowers on 4" stems in early summer. Sun or part shade in deep, well-drained, limy soil. Creeping stems form a dense mat of shiny dark green leaves. The double form resembles a carnation. Eastern Alps. Zones 3-8.
Silene caroliniana [kar-oh-lin-ee-ah-nah]. Densely tufted perennial with narrow, opposite, blue-green leaves. Clusters of white to deep pink flowers on 7" stems; an early summer bloomer; wedge-shaped petals. Grows well in acid dry woodland soil. Eastern U.S. Zones 5-8.
Silene schafta [shaf-tah]. Profusion of lavender-pink flowers on 6" stems, over dense tufts of light green leaves. Blooms in August and September. Sun or light shade in any soil. Caucasus. Zones 3-8.
Talinum okanoganense [tah-lye-num oh-kah-no-gahn-en-see]. Prostrate succulent with gray-green leaves, needle-like and fleshy, forming mats on which sit almost stemless satin-white flowers with prominent stamens. Not long-lived, but seeds freely. Likes gravelly, well-drained soil and sun. 'Pink Pearls' is a good selection. Washington and British Columbia in Okanogan Mts. Zones 3-8.
Thalictrum kiusianum [tha-lik-trum kee-you-see-aye-num]. Stoloniferous, low-growing, purple-leaved plant; the flower has no petals, but with its pinkish sepals and bright blue stamens, functions as a ground cover. Grow in light shade with humus-rich soil. Japan. Zones 3-8.
Thymus serpyllum [tye-mus ser-pill-um]. Downy gray-green leaves. Wide-spreading ground cover. Low evergreen with tiny aromatic leaves; pink or purple flowers in small terminal heads in late summer. The cultivar 'Coccineus' has bright red flowers. Europe, northern Africa. Zones 2-8.
Tiarella cordifolia [tee-ah-rell-ah kord-eh-fo-lee-ah]. In May, spikes of dainty white to pink flowers on 6-12" stems rise over a rosette of maple-shaped leaves, which turn red in the fall. A woodland native, easily grown in the garden. Eastern U.S. Zones 3-8.
Tulipa tarda [too-lip-ah tar-dah]. Starry, white 2" flowers with a central yellow eye on a 5" stem in early May. Full sun, scree. Central Asia. Zones 2-6. T. linifolia, brilliant red with a jet-black center, is better in the Southeast, up to Zone 8.
Vancouveria hexandra [van-koo-ver-ee-ah heks-an-drah]. Grows as a ground cover in the redwood forests, preferring deep shade and moisture. It has small feathery leaves and panicles of small pointed white flowers resembling epimedium. Blooms May to July. Pacific coast. Can be invasive in the Northwest. Zones 3-7. V. planipetala is excellent in Zone 8.
Veronica liwanensis [veh-ron-eh-kah lye-wan-en-sis]. Very prostrate foliage, dark green and glossy. In late spring, blue flowers with white centers. Full sun. A recent introduction from Turkey. Zones 3-7.
Veronica prostrata [pro-strah-tah]. (syn. V. rupestris). Tufted peren-nial with heavy gray stems, small leaves one-half to 3/4" long. Spikes of cobalt blue flowers emerge from the leaf axils. Several color forms in white, pink, and purple are available. Excellent ground cover in bright shade. Europe. Zones 3-8.
Veronica spicata [spih-kah-tah]. Neat lance-shaped leaves about 2" long on a 15" plant. Profuse blue or pink flowers on compact spikes from June to August. There is a very dense dwarf form 'Nana'. Northern Europe and Asia. Zones 3-8.
Viola pedata [vee-oh-lah peh-dah-tah]. As its name indicates, the finely divided leaves resemble a spread-out bird foot. Its spurred blue (or blue and violet) flowers are borne on 8" stems. Blooms from April to June. Will grow in sandy spots and rock crevices. Many violas are weedy and invasive; this one is not. Eastern U.S. Zones 3-9.
Zauschneria californica [zowsh-ner-ee-ah kal-eh-for-neh-kah]. California Fuchsia, Hummingbird Flower. Tubular red, 1-1/2-2" flowers grow in racemes on tall stems. Spreading by underground stems and not demanding a steady water supply, this plant sprawls over banks and rock walls, attracting hummingbirds from August until frost. Coastal California. Zones 7-10. However, the subspecieslatifolia from the mountains of Oregon is shorter and hardier, to Zones 5 or 6 with perfect drainage.