Rock Garden Plants
Rock plants are so
numerous that only the best of the different families can be mentioned.
Acaena - Dwarf plants for
carpeting. Only the New
Zealand variety (A.microphylla)
should be grown, and that for the sake of its crimson spines.
- The best of the rock garden kinds are Umbellata, with silver foliage and white flowers, and
Tomentosa, bright yellow. A fairly dry soil suits them best.
Adonis - Pheasant's Eye. A very
precious plant. A.vernalis (Ox-Eye), forms dense clumps of fern like foliage, from which rise large yellow
flowers. It blooms in spring, and is suited to a good loamy soil. Division or seeds.
AEthionema - An Alpine sub-shrub.
A.grandiflorum, forms dense spreading masses of foliage, covered with stout racemes of rosy flowers. Owing to
its prostrate habit it is useful for mantling the edges of rocks. Well drained loam. Seeds. This is quite one of
the loveliest of Alpine plants.
Alyssum - Madwort. A charming
spring flower. A.saxatile (Gold Dust) with its brilliant corymbs, blooms in autumn as well as spring.
Androsace - The best kinds are : A.carnea, Glacialis, and
Anemone - Wind-flower. A.apennina,
Antennaria - Cat's Ear. Dwarf
plants, of which A.tomentosa forms a silver carpet of foliage. A.dioica, with pink flowers, is worth growing.
Anthemis - Rock Camomile. A.aizoon
forms pretty tufts, with daisy like flowers.
Anthericum - St Bruno's Lily. The
lily of the Alpine pastures. A deep, sandy soil suits it, and the roots may be divided in autumn. A carpeting
of Saxifrages or other dwarf
plants look charming as a groundwork for a clump of St Bruno's Lily. A.liliastrum.
Arabis - Rock Cress. Well known and
invaluable. A.albida (White Rock Cress) and rosea a deep pink form, should be grown. Succeeds in any
Arenaria - Sandwort. Beautiful
plants, with compact masses of foliage, and myriad blossoms. A.balearica (Creeping Sandwort) and the Mountain
kind (A. montana
), should be in every rock garden. Seed
Armeria - Thrift. Dense tufts of
grass like foliage, with rosy flowers. A.cephalotes (Great Thrift), and A.caespitosa
(Tufted Thrift) are suitable for association with tall and dwarf plants respectively. Poor sandy soil.
Aubrietia - Purple Rock Cress.
Though common rock plants, they are of the utmost value. A.deltoidea and A.groeca are among the best. Any poor
gritty soil will grow Aubrietias, and they are readily increased, either by seeding or division.
Bulbocodium - Spring Meadow
Saffron. Among the spring flowers in the rock garden, the deep, rosy flowers of B.vernum are very beautiful.
Warm, sandy soil. Division of the bulbs.
Campanula - Harebell. One of the
most beautiful families for the rock garden, The Carpathian Harebell (C.carpatica) bears light blue flowers at
midsummer. C.caespitosa (Tufted
Harebell) is excellent for rock steps and the edges of stone flags, the American Harebell (C.pulla), a lovely
kind, does best in slight peat and sand.
Other good varieties
are Cenisia and Garganica, the latter suited to rock ledges, over which its pale blue flower racemes hang in great profusion. Campanulas
are so charming that in their case we cannot have too many species.
Cerastium - Mouse-ear Chickweed.
Dwarf, silverleaved Alpines, bearing numerous white flowers from May to July. The variety Biebersteini is
easily grown and is one of the best.
Cheiranthus - Wallflower. For rock
garden grouping, the bright orange variety Marshalli is the finest. The Alpine Wallflower (C.alpinus, syn. Erysimum
ochroleucum) is valuable for the joints of rock walling. The perennial Wallflowers thrive in poor soil and a
dry position in winter. Cuttings.
Colchicum - Meadow Saffron. Drifts
of the rosy flowered C.autumnale look exquisite in the grassy approaches to the rock garden. The leaves die down
before the blossoms appear, hence the necessity for a carpeting of grass or dwarf Alpines. They are easily
grown, increase freely and brighten the garden at a time when flowers are scarce.
Coronilla - Scorpion Senna. Though
little grown, this is a desirable plant, C.iberica forms dense tufts of trailing foliage,
which in June become studded with vivid yellow blossoms. C.varia, with pink and white flowers, is also good.
A fair depth of soil is essential.
Dianthus - Pink. This large family
includes several species of value. The Cheddar Pink (D.caesius) thrives in gritty crevices between adjacent
rocks. On rich soil it soon dies. D.deltoides (Maiden Pink), a charming pink spotted
variety, is of particularly easy culture. The Glacier Pink (D.neglectus) thrives in sandy
loam, its dwarf tufts of foliage and myriad rosy flowers producing a charming effect on the higher
Dodecatheon - American Cowslip.
These plants should be grown in similar positions to the Alpine Primulas, the roots being divided from time to
time and replanted in sandy
loam. D.integrifolium blooms in
March, the flowers a purplish crimson. D.meadia, with drooping umbels of purple flowers, is
another good kind.
Draba - Whitlow Grass.
Among small mosses and in rock crevices a few plants of D.aizoides, with their brilliant cushions of yellow
flowers, are interesting Alpines.
Dracocephalum - Dragon's-head.
Easily grown plants of the Sage family. D.grandiflorum is covered in July with dense
clusters of rich blue flowers. Division or seed.
Erigeron - Fleabane. Though most of
the family are border plants, E.alpinum grandiflorum should be grown in the rock
garden. The mauve, daisy like flowers are produced very abundantly in late summer. Well drained loam.
Erinus - Wall Erinus. On bare rocky
places the racemes of lilac flowers and tufted foliage of E.alpinus are most welcome.
Geranium - Cranesbill. The two rock
garden kinds are G.argenteum and G.cinereum. Among the smallest Alpines, the clusters of red flowers are
Helianthemum - Sun Rose. There are
few more beautiful rock plants than these dwarf trailing shrubs. For mantling sunny ledges they are unequalled.
They are quite hardy and succeed in any sandy loam. From a long list of varieties, we may choose H.pilosum,
white, H.grandiflorum, yellow, and H. roseum multiplex, double pink. When in full bloom
these flowers are of exquisite beauty.
Houstonia - Bluets. A grassy little
plant, with numerous dainty blue flowers on slender stems. A sheltered corner with sandy soil should be
Hutchinsia H.alpina, a good white
flowered Alpine for association with the dwarfest plants. Sandy soil.
Leontopodium - Edelweiss. The well
known hoary leaved plant, with
yellow flowers. It is of the easiest culture and will always be of interest.
Linaria - Toadflax. For rock
crevices and the joints in rough steps L.alpina is useful. L.antirrhinifolia forms dense tufts covered with
purple flowers, and is a bright note of color among the stones. Moist, sandy soil.
- Flax. The yellow L.flavum and the exquisite Narbonne Flax (L.narbonnense) with sky blue flowers, are both
good. The latter should be planted in somewhat rich soil, if it is to bloom freely
- Campion. The best of these is L.lagascae with bright rosy flowers. Rock fissures with gritty soil.
Mertensia - Little known but very
graceful plants. M.dahurica and
M.alpina, both with drooping clusters of bright blue flowers, may be grown in sandy soil. Owing to their slender
habit, the Mertensias should be given sheltered positions.
Myosotis - Forget-me-not.
M.alpestris is a gem for rocky places. Its light blue flower masses harmonise perfectly with those of its
relative M. dissitiflora, which are of a deeper shade. Moist loam.
Omphalodes - Navelwort. Well
drained sandy loam suits these charming rock plants. O.Luciliae, with glaucous foliage and lilac flowers, is
hardy, and O.verna (Creeping Forget-me-not) of trailing habit, bears a profusion of bright blue and white
blossoms. Seed or division.
Onosma - Golden Drop. Dense tufts
of evergreen foliage, with drooping clusters of bright yellow flowers. O.tauricum does well in a sunny aspect
with deep loam and broken grit.
Papaver - Poppy. The Alpine Poppy
(P.alpinum) is worthy of a place in the rock garden. The common form has yellow flowers, with white centers.
Petrocallis - Rock Beauty. On small
sunny ledges in good soil this is a gem. P.pyrenaica bears a profusion of sweetly scented, lilac flowers on
dense tufts of foliage. Seed.
- Of these the Moss Pink (P.subulata), erroneously known as P.setacea, is a dainty little evergreen with rosy
flowers, rambling freely over stones and garlanding ledges. P.setacea is equally delightful, with soft pink
flowers, it may be massed with its sub-variety P.s.violacea, whose deeper crimson flowers afford a pretty
Polygonum - Knotweed. The Himalayan
variety P.affine is a good plant for moist places, its spikes of rosy red flowers producing a delightful effect.
The foliage is brilliantly colored in autumn. P.vaccinifolium is best in rough, rocky places where it can ramble
at will among stones and boulders.
Potentilla - Cinquefoil. Plants of
easy culture, thriving in exposed places in loamy soil. The best of the dwarf Alpines are P.nitida (Shiny
Cinquefoil), with silvery leaves and rosy flowers: P.alpestris (Alpine Cinquefoil), much larger, with
bright yellow blossoms, and P.alba (White Cinquefoil), a dwarf, variety, bearing white and orange
Primula - Primrose. One of the
largest and best of all the rock plant families. For rock gardens the following should be grown: P.denticulata,
P. farinose, P.rosea, and P.sieboldi.
Pyrola - Winter-green. Beautiful
plants for half shade. P.rotundifolia, with tall stems and drooping racemes of numerous white flowers, should be
grown together with its sub-variety P.r.arenaria. The flowers are sweetly scented. Light sandy soil.
Ranunculus - Crowfoot Buttercup. Of
simple culture, the Buttercups thrive in any fairly moist sandy soil. R.alpestris, with deep glossy foliage, and
large pure white flowers and clustered yellow stamens, is one of the best.
R.glacialis, in the coolest positions, and R.amplexicaulis (White Buttercup) are good for rock
Sanguinaria - Bloodroot. A very desirable
plant. S.canadensis forms dense clusters of large glaucous leaves, on which numerous white flowers with yellow
stamens rest like miniature Water Lilies. Division.
Saponaria - Soapwort. The rosy flowered
S.ocymoides is a beautiful plant for mantling the edges of rocks. Poor, dry soil.
Saxifraga - Rockfoil. Perhaps the best
known of all rock plants. S.cotyledon (Pyramidal saxifrage), S.longifolia, S.oppositifolia, S.umbrosa (London
Sedum - Stonecrop. Hardy dwarf plants for
rock crevices and the higher ledges. S.acre (Wall Pepper) grows freely
on walling, and is bright by reason of its vivid yellow flowers. S.stoloniferum (Purple Stonecrop), with large leaves, and S.sieboldi, useful for draping
the edges of stones, are among the best.
Sempervivum - Houseleek. Dwarf succulents,
thriving in the poorest soil. The Cobweb Houseleek (S.arachnoideum)
is very quaint, with its myriad silver leaf rosettes covering the ground like a web. S.triste, with red leaves,
is distinct. Offsets.
Silene - Catchfly. Invaluable for rock
gardens. The Alpine Catchfly (S.alpestris) is a hardy white flowered kind. S.virginica (Fire Pink), though impatient of too much moisture, is very beautiful. It has
vivid scarlet flowers. Seed.
Soldanella - In a moist, deep soil between
the higher rocks, Soldanellas are delightful. S.alpine has bellshaped
flowers of a pale blue color, the carpet of feathery foliage in this variety giving an added
charm. They must not be grown near
large plants. Division.
Thymus - Thyme. On the outskirts of
the rock garden where there are no small plants, masses of creeping Thyme are very beautiful. The poorest and
driest soil will suffice. Two beautiful kinds are the wild white Thyme (T.serpyllum albus) and the
woolly-leaved Mountain Thyme (T.lanuginosus), with purple flowers. Full exposure to sun.
Tiarella - Foam Flower. An
exquisite plant of the hardiest description. The trailing foliage is tinged with red and bronze, and the
graceful spikes of creamy pink flowers, when massed, give the rocks and stones an almost foam flecked
appearance. Frequent division.
Veronica - Speedwell. The trailing
kinds should be found in all rock gardens. V.rupestris and V.prostrata are good. V.spicata, a native plant, soon
covers the ground with neat patches of foliage. Sandy loam.