ROCK GARDEN PERENNIALS
Achillea Compositae Yarrow, Hilfoil
Resembling the field yarrow, but dainty, mottled, and tufted. The leaves, some finely cut and ferny, wear thick wool coats. The saucy flowers are in heads, some flat-topped and not unlike daisies.
ageratifolia aizoon (Anthemis aizoon)—Six-inch mat of silver-haired, uncut leaves topped with bright white flowers in May and June.
clavennae—Tufts of hoary, fine-cut leaves less than a foot high, tight round white flower heads three-fourths of an inch across in May and June.
tomentosa—Best-known little species, quickly makes a thick mat of semi-evergreen gray-green leaves six inches tall. It has sunny yellow flowers from June to midsummer. The variety aurea has more golden flowers and blooms earlier; nana is a true midget and makes a thick carpet studded with many white flowers. Five-inch ‘Moonlight’ has flowers of sulfur yellow, and greener foliage.
umbellata—Four-inch mounds of fuzzy, silvery, ferny leaves. It has cream-white flowers in June and is evergreen in temperate areas.
CARE. Any soil, even sandy or poor. Dryish to moist. Sun or very light shade. Easy to grow.
PROPAGATION. Division in spring or fall, seeds (flowers the second year).
SPECIAL USES. Rock plantings, dry-wall planting, edging, ground cover, pavements.
Aethionema Cruciferae Stone-Cress, Persian Candytuft
This is a heathery little shrub-like perennial with slim leaves and steely-blue needles, cheerful clusters of flowers at the stem tips in May and June. It is often compared to a minuscule daphne.
armenum—Neat tufts of short, sharp leaves and petite pink flowers in June. It is never over four inches high.
iberideum—Low, crowded, and cushiony-minute with gray-green leaves and large white flowers in short clusters. This one is earlier than other varieties, blooming even in April if the weather is favorable. (Needs gritty soil with some lime.)
schistosum—By comparison this one is a giant growing to eight or ten inches, with two-inch leaves and fragrant pink flowers.
CARE. Soil light, sandy, well-drained, and gravelly; dry; sun. Hardy in southern New England. Give protection in severe winters.
PROPAGATION. Cuttings in summer, division and seeds in spring.
SPECIAL USES. Rock gardens, dry-wall planting, edging, borders.
Ajuga Labiatae Bugle
This is a low, creeping or spreading perennial with pinwheels of rather coarse leaves and small blue flowers which come in May and June. It is of miniature height and should only be planted where you can control it, or want it to spread. Some of the better-known varieties are:
genevensis—Oval toothed leaves, light green. Flowers deep blue.
pyramidalis—Less likely to spread and stays neat and small. Flowers blue and slightly larger than those of other varieties.
reptans—Also known as carpet bugle, it is nearly supine, with stems that root as they creep. Flowers blue or purplish. Variety alba has white flowers; variegata, foliage marked with cream and pink. Rubra pink flowers.
‘Silver Beauty’—Compact and ground-hugging. White markings on leaves give a silvery appearance. Blue flowers.
CARE. Ordinary soil, even poor; sun or part shade; dry. Plant in fall or spring six inches apart. Easy to grow.
PROPAGATION. Seeds in spring, division.
SPECIAL USES. Rock gardens, dry-wall planting, ground cover, edging.
Alyssum Cruciferae Madwort
Plushy, mat-forming, like a silver-gray rug with flecks of white or golden flowers in spring and summer. The grayish leaves are small, the flowers in thick clusters. Popular forms are:
alpestre (serpyllifolium)—Three-inch gray carpet with bright-yellow flowers through June.
montanum—Fragrant gold flowers in June; about eight inches high.
mulfenianum—Smaller (four-inch) version with balls of yellow flowers from May to June.
saxatile—basket of gold—Blooms in May; nine inches high; spreads thickly. Variety compactum is more compact and shorter; about eight inches. Variety citrinum has lemon-yellow flowers.
spinosum—Dense growth, shrubby and spiny, about eight inches high. White flowers sometimes tinged with pink, in June and July.
CARE. Any ordinary soil with drainage. Sunny, open location. Plant in spring or fall six to eight inches apart.
PROPAGATION. Seeds in fall, division of roots in spring.
SPECIAL USES. Rock gardens, borders, dry walls, pavements, edging, carpet for bulbs, ground cover.
Anemone Ranunculaceae Windflower
One of the earliest to bloom in the spring, it has lacy leaves and colorful flowering saucers not made up of petals but of sepals (leaves that encircle the flowers at the base).
apennina—Tuberous species six or seven inches high with deeply cut leaves; arrives in March with bright, sky-blue flowers. Variety alba has white flowers; purpurea, rich lavender-rose.
blanda—Resembles apennina but is slightly larger and has darker flowers.
nemorosa—European wood anemone—Similiar to American forms. Variety alleni has lavender flowers. Variety rosea, pink.
palmata—Six-inch dwarf with whorls of leathery leaves, golden-white flowers in May or June. The flowers of the variety albida are heavenly white with gold centers.
pulsatilla—pasque flower—A more robust alpine growing to eight inches tall. Hardy even in Maine rock gardens. Flowers are purple-blue bells that come early and last as long as the weather is cool. Its finely cut leaves are softened with silky hairs. Other varieties are alba, white; rubra, plum red; and camla, silvery lilac surrounded by white.
CARE. Rich sandy loam with leaf mold. Part shade for some varieties.
PROPAGATION. Seed in late fall, root division in early spring.
SPECIAL USES. Wild gardens, rock gardens, forcing, flower beds.
Antennaria Compositae Pussy-Toes
This is a furry little creeper with flat, silvery, spoon-shaped leaves and bristly flowers sometimes dried as everlastings.
dioica—Fast-creeping carpet with pink-tipped flowers in spring.
microphylla (parvifolia)—Western native, slower growing, with white flowers.
neodioica—Eastern native that makes a low mat of silver-hairy leaves and sends up pink-tipped white flowers in early summer.
CARE. Sandy, even poor, soil; full sun; dry. Cut off leaves after flowering to make neater plants.
PROPAGATION. Seeds and division.
SPECIAL USES. Rock walls and pavement.
Aquilegia Ranunculaceae Columbine
Hardy little perennials with two-or three-part leaves like clover but often cut or indented on the edge, and drooping or noddling flowers with flaring sepals and spurs of different sizes and shapes.
akitensis—Six-inch Japanese doll with stemless blue-green leaves and large lavender-blue flowers with yellow at the center. June flowers.
discolor—Alpine with glowing blue flowers, white inside and frosty-green leaves. Five inches tall.
flabellata nana-alba—fan columbine—Three divided leaves like blue-green fans, lustrous white flowers in May.
jonesi—Diminutive, two to three inches tall. Small leaves in small mounds, flowers upturned and deep blue in June.
saximontana—Alpine with two-inch tufts of crisp leaves; aquamarine flowers with yellowish sepals on four-inch stems in April.
CARE. Soil light and sandy, with leaf mold; drainage; shade or semishade. Hardy. Plant in fall.
PROPAGATION. Seeds in the spring (flowers the following year), division in the spring.
SPECIAL USES. Rock and wall planting, wild-flower gardens, beds.
Arabis Cruciferae Rock Cress
Mat-forming perennials with blankets of hairy leaves under spreads of flowers rather like stocks or candytuft. They flower in spring or summer and are often fragrant.
albida—Unless the form is marked “compact” the species may top ten inches. Leaves green and woolly, flowers white (in April and May). Variety flora plena is about six inches tall with double white flowers; rosea, orchid pink and single; variegata, white-marked leaves. ‘Pink Charm’ is single with bright-pink flowers.
blepharophylla—Clusters of deep-green leaves with eyelashes on the edge; pink-purple flowers in April. Height, four inches.
procurrens—Matting plant with creeping stolons, white flowers in May. Dwarf variety, stari, spreads slowly and stays under four inches.
CARE. Medium, even poor, soil; warm and sandy. Not too moist. Sun or light shade. After flowering cut back straggly stems.
PROPAGATION. Division (in spring or fall), seeds, cuttings.
SPECIAL USES. Rock gardens, wall planting, ground cover, edging.
Aster alpinus Compositae Rock Aster
Small leaves mat closely to make a mound four inches high. The flat lilac daisy-like flowers come in June and July on eight-inch stems. The variety superbus is slightly larger; albus has white flowers. ‘Goliath’ is a variety with flowers ranging from yellow-centered lavender to near-purple. ‘Spring Charm’ is a midget with lavender-pinkish flowers.
CARE. Any good soil, full sun.
PROPAGATION. Seeds in the spring (flowers the next year).
SPECIAL USES. Rock gardens, borders, edging.
Bellis Compositae Daisy
Miniature daisies of cheerful charm, some varieties barely six inches tall.
perennis—English daisy—Nests of green leaves sprinkled in spring and summer with flowers of white, rose, or red. Several new strains are now being offered in singles, doubles (some have quilted petals), and varied colors.
rotundiafolia caerulescens—alpine daisy—Soft-blue flowers all summer long.
CARE. Fertile soil; moist, but good drainage; sun or semisun. A cool summer produces larger flowers. Not suitable for hot climates.
PROPAGATION. Seeds (flowers following year), division in cool weather.
SPECIAL USES. Rock gardens, edging, ground cover.
Campanula Campanulaceae Harebell, Bell Flower
These are the beloved bell flowers which should be included in all gardens. Included on page [264] are varieties that are easy to get and grow.
CARE. Light loamy soil, slightly on limy side; drainage. Sun, except dwarfs, which take light shade. Remove dead flowers. Shelter with evergreen boughs in severe winter.
PROPAGATION. Division in early spring or fall, seeds (plant as soon as ripe), cuttings.
SPECIAL USES. Rock gardens, walls, borders, edging, pots, and baskets.
Cerastium Caryophyllaceae
Perennial creepers and carpeters with slim silk-hairy leaves and showers of white flowers with an over-all effect of soft fuzzy wool. Maximum height six inches, but most plants less.
alpinum lanatum—Smallest downy leaves, white flowers in clusters in June and July.
bierbersteini—Longer leaves, flowers one month earlier.
tomentosum—snow in summer—This, the most popular species; quickly forms a large mat like a silver carpet under starry white flowers in May and June. It is said it will grow in pure sand.
CARE. Ordinary soil, sun, dry. Easy to grow.
PROPAGATION. Seeds (plant in fall or spring), division, cuttings after flowering.
SPECIAL USES. Rock gardens, edging, flower beds, ground cover.