There are hundreds of rock garden plants that might be grown. All that can be done here is to attempt to divide the plants up into variousand make mention of just a few which I have found to be or particularly attractive. The reader can increase his knowledge by going to good shows, by studying the garden press, by looking at the catalogues of well-known firms and of course by personal experience.
Spreaders and Ramblers
The plants that come into this group are easy to grow and are not fastidious as to soil or. They can be planted any time in the early autumn, or from March to May. They like an open situation but they will put up with partial shade.
ACHILLEA UMBELLA TA Silvery, white in June, 150 mm (6 in) high.
AJUGA REPTANS PUPUREA Purplishand blue flowers in May and June, 150 mm (6 in) high.
ALYSSUM SAXAT1LE COMPACTUM Greyish green leaves, yellow flowers from March-May, 225 mm (9 in) high.
AUBRIETIA Numerous varieties, varying in colour, pink, red, mauve, purple. April-June, 100 to 150 mm (4 to 6 in) high.
CAMPANULA ROTUNDIFOLIA Small green leaves, numerous blue-bell shaped flowers. June and July, 225 mm (9 in).
DIANTHUS DELTOIDES Spiky leaves and small rose-pink flowers June-August 300 mm (12 in). ERODIUM Many kinds which have geranium-like flowers followed bypods which look like birds’ beaks.
HELIANTHEMUM Many varieties of rock roses which flower from June-July, in a varied shades of yellow, orange, pink and red. Like hot dry positions.
IBERIS SEMPER VIRENS An evergreen candytuft bearing masses of pure white flowers from June-August, 225 mm (9 in) high.
OXALIS Most of the plants spread rapidly and flower from March-October. O. floribunda has pink flowers; O. corniculata has orange flowers.
SAX1FRAGA Many different types, some with red, some with white flowers. They form dense tufts of soft green foliage and produce either white or red flowers according to variety, some from May-July and other in April and May.
SEDUM The stonecrop family, which have small thick succulent leaves and starry flowers.
VERONICA SAXATIL1S Bears rich blue flowers with crimson eye and has trailing. Flowers from June-September, grows 75 mm (3 in) high.
VIOLA CORNUTA Bears bluish purple flowers from May-October on150 to 225 mm (6 to 9 in) high. There is a white variety.
The Bulbs and Tubers
There are a number of baby bulbs and tubers that look well in the rock garden. The autumn and winter flowering kinds should be planted in August but September or October is soon enough for those that bloom in the spring.
Those that grow about 300 mm (1 ft) high should be planted 75 to 150 mm (3 to 6 in) deep and 100 to 200 mm (4 to 8 in) apart. The remainder should go in 40 to 100 mm (1½ to 4 in) deep and 25 to 75 mm (1 to 3 in) apart according to the size of the bulb. (The larger the deeper.) They all of them like an open situation and plenty of sun with the exception of the Trillium which prefers partial shade. Most of them can be left down for years – the tulips perhaps benefit by being lifted each alternate year.
Bulbs and Tubers to Grow
ALLIUMS Onion-like plants with narrow leaves and small heads of flowers bloom from June till July. 300 to 450 mm (12 to 18 in) tall.
ANEMONES Special rock garden kinds like Blanda which flowers from January until March and bears blue or pink flowers; 150 mm (6 in) high.
CYCLAMENS The dwarf species like Africanum which flowers in the autumn, a bluishwith 100 to 150 mm (4 to 6 in) stems, or Coum, a rosy red which flowers from February till March on 100 mm (4 in) stems.
ERANTHIS The cheery little winter aconite which has bright yellow flowers like those of a buttercup. Hyemalis, in flower from January-March and only grows 75 mm (3 in) tall.
ERYTHRONIUMS Dog’s tooth violet, bears flowers something like those of a cyclamen from April-May.
FRITILLARIAS bear well-shaped flowers beautifully marked with fine lines. F. citrina is a pale yellow which flowers in May on stems 200 to 225 mm (8 to 9 in) high.
IRISES There are many dwarf bulbous sorts that are very suitable, likealata which flowers in January and /. reticulata a sweet-scented violet-purple which is at its best in February.
NARCISSUS There are many babies in this daffodil family. The Hooped Petticoat narcissus is at its best in April and prefers a moist situation. It is only 150 mm (6 in) tall. The cyclamen-flowered daffodil is the same height and is in bloom in February and March. N. minimus is the smallest of all trumpet-daffodils only 75 mm (3 in) tall, at its best in February. Angel’s Tears is a small creamy white narcissus, which flowers in March. It is 150 mm (6 in) tall.
TRILLIUM GRANDIFLORUM bears white flowers in April and May in three. 150 to 300 mm (6 to 12 in) high. TULIPS There are many of the tulip species suitable for the rock garden, T. greigii for instance is a vermilion scarlet which grows about 300 mm (1 ft) tall and is at its best in May. T. kaujmanniana is a creamy white with a golden base plus a dull broad strawberry stripe outside. Grows 200 mm (8 in) high.