Best Plants For Rock Gardens

Acantholimon

This is a small genus, liking neutral or acid soil, which provides interest in winter with the persistent cup-like bracts. One of the easiest to grow is the Armenian Acantholimon glumaceum with loose cushions in rosette formation. This species has deep green needle-shaped, spine-tipped foliage and the rosy-pink flowers appear in

June on 6-in. Stems. You can expect the prickly thrift to have a spread of 9 in. in maturity. It is increased by cuttings in August.

Achillea

The milfoils or yarrows are mostly grown for their finely cut aromatic foliage. Achillea ageratifolia has Achillea ptarmicaa tufted habit and is only 2 in. high with deeply toothed, narrow, intensely downy, white leaves and white daisy flowers. It comes from Greece. A. lewisii, a garden hybrid, makes a mat of grey-green cut foliage and has light yellow flowers on 6-in. Stems. Both have a long flowering season from June to July and can be increased by cuttings in July.

Aethionema

This genus contains a number of easy rock plants known by the common name of the Persian candytufts. They are well represented by Aethionema armenum, which has narrow blue-grey leaves and neat heads of pink, veined flowers on 6-in. Stems from May to August; and Warley Rose, an improved garden form, with larger, deeper pink-coloured flowers. Both are 4 to 6 in. high with a spread of 12 in. and are suitable for a dry wall as well as the rock garden. Cut back after flowering and propagate by cuttings in June.

Allium

There are a number of ornamental onions which make an attractive display in the rock garden in August. They are all about 9 in. high. Allium cyaneum is a Chinese species with grass-like leaves and semi-pendant blue flowers. A. cyathophorum farreri (syn. A. farren), with pendant, bell-shaped, reddish-purple flowers, is from Kansu A narcissiflorum is a native of south eastern Europe and it bears semi-pendant bright rose flowers. Seed is an easy method of increase in March.

Alyssum

The madworts are evergreen plants from 3 to 9 in. high with a spread of 24 in. They are ideal for a wall and together with arabis and aubrieta will provide a riot of early spring colour. They should be cut back after flowering and can be propagated by cuttings in July.

Alyssum alpestre is a sub-shrub from the European Alps with grey oblong hairy leaves and pale yellow flowers in clusters. A. saxatile, with its descriptive common name of gold dust, is a sub-shrub with silver-grey leaves. The clustered flowers are golden yellow and named varieties include citrinum, lemon yellow; compactum, smaller, bright yellow; plenum,

double yellow, and variegatum, yellow and grey-green leaves.

Andromeda

These are evergreen plants for a shady lime-free rock garden and the edge of a pool. Andromeda glaucophylla is a dwarf shrub only 6 in. high and 12 in. wide with narrow grey-green leaves and pale pink urn-shaped flowers in May.

A. polifolia, the bog rosemary, is a native of the northern hemisphere and has deep green leaves with pale pink flowers on 6-in, stems in May. Its varieties compacta and minima from Japan are both smaller with foliage variations. Cuttings are a ready means of increase in May.

Androsace

The rock jasmines are true alpine plants with a world-wide distribution. Their flowering period is April to May and they are from 2 to 4 in. high and 4 to 15 in. wide. All require faultless drainage and can be increased by seed in March or cuttings in June.

Androsace carnea, native to Europe, makes rosettes of narrow, evergreen foliage and the flowers are bright rose with a yellow eye. Good varieties are brigantiaca, white; halleri, deep pink, from Switzerland, and laggeri, smaller rosettes with bright pink flowers from the Pyrenees.

A. sarmentosa is a native of the Himalayas and it forms rosettes of silver-grey hairy foliage. The large pale pink flowers are borne in clusters. The varieties Brilliant, deep rose red, and chumbyi with compact clusters of deep pink flowers from the Chumbi Valley are recommended.

Anemone

There are a number of the charming, free-flowering windflowers suitable for the rock garden. Anemone baldensis is a herbaceous perennial with deeply cut leaves and starry white flowers, tinged blue on the reverse. Native of Europe, it blooms on 3-in. Stems in May and June. It requires a moist spot. Divide in July.

Anemone blanda is a bulbous plant with incurving segments of deeply cut green foliage and, during March and April, blue to purple-blue flowers on 4-in. Stems. The variety atrocaerulea is deep blue and rosea is bright pink.

A. obtusiloba patula, the blue buttercup, comes from the Himalayas. It has rosettes of hairy three-lobed green leaves. The blue flowers are cup shaped and they appear in May and June at the end of prostrate shoots. Propagation is by seed in March.

Antemiaria

The blue flowers are cup shaped and they for choice bulbs as well as being attractive plants. At home in the northern hemisphere, Antennaria dioica forms 2-in, high mats of evergreen, grey-green leaves and in May and June clusters of pink flowers backed with green, pink-tipped bracts. The variety minima is less than 1 in. high and Nyewood has the attractive combination of silver leaves and crimson flowers. Division in August is an easy means of increase.

Anthyllis

There is one species and two forms of the kidney vetch which are very attractive. The European Anthyllis montana makes mats of silvery downy leaves 3 in. high and 12in. Wide with rose, clover-like flowers over a long period from June to September. Alba, white, and rubra, deep rose red, are the good varieties. Increase by cuttings in May.

Aquilegia

The columbine is a widely distributed genus of herbaceous perennials containing some delightful miniatures. Aquilegia bertolonii is about 4 in. high and forms tufts of grey-green leaves with violet-blue spurred flowers in May. It comes from Italy. A. canadensis, from north west Africa, has tufts of green cut leaves and in May red flowers with yellow petals on 8-in. Stems.

A. flabellata nana is native to Japan and looks well planted in a trough. It has grey-blue cut leaves on 4-in, stems. And large blue and cream flowers in May. Propagation is by means of seed which should be sown in July.

Arabis

This is a family containing some gems which are all ideal for planting on a sunny wall together with aubrieta for an early spring display. The following species and varieties of the rock cress are to be recommended.

Arabis alpina is a close compact plant with oval leaves and white flowers. It comes from Europe and is about 6 in. high and 15 in. wide.

A. caucasica (albida) makes a mat about 18 in. wide with leaves in grey rosettes and fragrant white flowers clustered on 9-in. Stems. It, too, is a native of Europe. Its variety billardieri is rose and fore pleno has double white flowers.

A. ferdinandi-coburgi variegata is a form with well-marked bright green foliage which has a marginal band of cream. The flowers are white on 6-in. Stems. They are all evergreen and should be cut back after flowering. Increase by cuttings taken in July.

Armeria

The sea pinks or thrifts are all similar but the one listed here is possibly the best. Armeria caespitosa Bevan’s Variety forms dense 2-in, evergreen cushions of bright green soft spiny leaves about 6 in. across. The flowers are rounded heads of deep cerise red on short stems in May and June. Increase by cuttings in June.

Artemisia

This is a family of aromatic silver-grey foliage plants useful as foils to other plants. Both the species mentioned are evergreen. Artemisia glacialis is a close sub-shrub about 2 in. high and 6 in. wide with narrow silver-downed leaves. The June flowers are yellow. It comes from central Europe and is a good subject for trough culture.

A. schmidtiana nana is Japanese in origin and makes a plant of 2 in. high and 9 in. wide with narrow deeply cut silver-grey leaves. The pendant, yellow flowers appear in September. Both can be propagated by cuttings in July.

Asperula

The woodruffs make good dwarf evergreen plants for the rock garden or trough and are easily increased by cuttings taken in July. Asperula 1ilacflora caespitosa is a native of south east Europe and it makes a mat of bright green heath-like foliage only 2 in. high with prostrate stems of lilac-pink flowers in June.

The Greek species suberosa forms a 4-in, mat of down-covered grey leaves up to 8 in. wide. The long tubular pink flowers which first appear in May continue over a long period.

Aster

The starworts are dainty wildlings, providing colour during late spring. The species Aster alpinus, from Europe, has typical large daisy flowers of lilac purple with a golden eye on 4 to 6-in, stems during May and June. It is a variable species, however, with many colour forms which include albus, white; roseus, pink; ruber, deep red and speciosus, bright purple. Division in September is a ready means of increase.

Aubrieta

Along with arabis and alyssum, this is one of the widest grown rock plants providing colour in early spring. The forms of Aubrieta deltoidea, the wall cress, are 3 in.

high and 24 to 36 in. wide making good plants for a dry wall. The species makes a compact carpet of grey-green hairy leaves and four-petalled mauve flowers in April and May. Good varieties include Barker’s Double, double, red; Blue King, blue; Bonfire, red; Bressingham Pink, double, pink; Church Knowle, deep lavender: Dr Mules, purple; Fire King, red; Green-court Purple, double, purple; Joan Allen, double, crimson; Magician, crimson purple; Russell’s Crimson, red; variegata argentea, pale mauve, leaves margined silver, and Wanda, double, red.

All should be cut back after flowering and propagation is by cuttings in June or division in September.

Berberis

The barberries are represented here by two forms of Berberis stenophylla which are ideal evergreen rock garden shrubs both about 12 in. high and 24 in. across with flowers in May followed by berries in September. Corallina compacta has spine-tipped bright green foliage, coral buds, yellow flowers and purple white-bloomed fruit. It is as attractive as it sounds.

Gracilis nana is equally lovely with yellow-flecked holly leaves which are a brilliant orange when young. The flowers are orange yellow and the berries purple. Propagate both by cuttings taken in July.

Calceolaria

The slipperworts are charming, herbaceous plants for a cool moist spot near a pool. They can be increased by division in April. Calceolaria acutifolia hails from Patagonia and from a pair of hairy green leaves are borne the pouch-like, golden-yellow flowers, dotted red on the reverse, on 6-in, stems during June to August.

C. tenella, from Chile, is a prostrate plant with minute light green leaves and, during June to August, up to three flowers on thread-like 1-in. Stems. These are golden yellow with crimson spots on the tips.

Campanula

The bell flowers are a large family of mid-season plants and they extend the flowering period in the rock garden until late August.

Campanula arvatica, from Spain, forms a mat of minute bright green foliage. Its dainty flowers are like violet-blue stars and they appear on 1-in, stems in June and July. It is excellent for planting in a trough garden.

C. carpatica is a Carpathian species with a large number of garden forms. All open bell-shaped flowers over grey-green foliage and are about 6 to 12 in. high with a spread of 15 in. They flower from June to August and include alba, white; coelestina, china blue; Isabel, violet, and turbinata, purple blue.

The Italian C. garganica forms rosettes

of kidney-shaped leaves and its white-eyed blue flowers are to be found in June on 6-in. Stems. It is a good wall plant with a spread of up to 15 in. across.

C. portenschlagiana (muralis) is a species from Dalmatia suitable for walls. It bears tufted rosettes of kidney-shaped green foliage. The star-shaped light violet-blue flowers are around from June to August on 3-in. Stems.

All can be increased by cuttings in June or division in April.

Cerastium

The well-known snow in summer should be avoided like the plague in small rock gardens but Cerastium alpinum lanatum, the mouse-ear chickweed from the European Alps, is a small plant with silky oval leaves and shiny white flowers on 2-in. Stems during May and June. It is a suitable subject for a trough as its ultimate spread is only 9 in. propagation is by division in July.

Chamaecytisus

There is only one dwarf broom suitable for the rock garden and that is Chamaecytisus pygmaeus from Turkey. It is about 4 in. high and 12 in. wide with prostrate stems and much cut narrow leaves. The bright yellow pea-shaped flowers are to be seen in June and it makes a good plant for a wall. Cuttings can be taken in June.

Chamaespartium

Chamaespartium delphinensis from the Pyrenees is a must for even the smallest rock garden or trough. It is only 3 in. high with zig-zagged branches and winged adpressed grey-green leaves. In June it is covered in a mass of golden-yellow, pea-shaped flowers. It prefers a lime-free soil and can be increased by cuttings in June.

Crocus

There are a large number of crocus species suitable for the rock garden or trough and the following will give a display over a long period. All are from 3 to 4 in. high and can be increased by seed or division.

Among those that flower in autumn (August to October) are Crocus byzantinus, flowers bluish purple, eastern Europe; C. kotschyanus, large, rose lilac, throat yellow, Asia Minor; C. speciosus, lavender blue, veined, Asia Minor, Persia, and varieties Artabir, lavender blue with deeper feathering, and Oxonian, bluish purple.

Those that flower in winter (November to February) include C. chrysanthus, flowers deep yellow, brownish-purple veining, Greece, Asia Minor, and varieties

Blue Bird, purplish blue, E. A. Bowles, rounded yellow goblets with bronze feathering, Moonlight, light sulphur yellow; C. imperati, bluish-mauve flowers, veined deep purple, southern Italy; C. laevigatus, feathered blue-mauve flowers, Greece.

The show continues from February to April with the spring-flowering types. C. balansae has goblets of bright orange with mahogany feathering, western Asia Minor; C. candidus, variable from white through cream to orange, Asia Minor; C. fleischeri, a snowy white species with orange-scarlet stigmata, Asia Minor; C. susianus, brilliant orange flowers with dark brown markings, Crimea.

Cytisus

There are some good prostrate species of the common broom for trailing over rocks and walls. Cytisus ardoinii, a native of France, is about 6 in. high with bright green leaves in threes and pea-shaped, golden-yellow flowers in May. C. procumbens which comes from the same district is smaller at 3 in. high but it has a spread of 24 in. The small oblong grey-green leaves provide a good foil to the bright yellow flowers of May and June. Both are increased by cuttings in June.

Daphne

The garland flowers are interesting dwarf shrubs with normally intensely fragrant flowers. Propagation of both the following species is by cuttings taken in June. Daphne cneorum, from Europe, is about 9 in. high with a spread of 24 in. It has narrow oblong leaves and clusters of rich deep pink fragrant flowers in May and June. D. collina is a native of Italy and Asia Minor. It grows up to 12 in. high and 18 in. wide and has oblong leaves and terminal heads of fragrant reddish-purple flowers in May.

Dianthus

The pinks are one of the backbones of the rock garden with many attractive flowering plants. Dianthus deltoides, the maiden pink, is from 4 to 6 in. high and 15 in. wide. It forms grey-green narrow foliage and deep pink flowers with a darker stripe in June and July. A native of Europe, it has produced a number of good colour forms. These include albus, white with a crimson zone; Bowles’ Variety, crimson-red flowers; glaucus, grey leaves and rose flowers, and the aptly named Huntsman which is scarlet pink.

D. gratianopolitanus (caesius) is the British cheddar pink. It is about 6 in. high and 12 in. wide with blue-grey foliage and deeply fringed rose-pink, fragrant flowers in June and July. Good varieties include Baker’s Variety, rose red; fore pleno, double, rose pink and Icombe, smaller, rose pink. Both the foregoing species and forms are ideal wall plants.

D. pavonius (neglectus) from south west Europe is only 3 in. high with smooth tufts of narrow green foliage. The large fringed flowers are bright rose with a green central zone and they are out in June and July. It is a good plant for a trough in a lime-free soil.

There are many named hybrids in most nurserymen’s catalogues including Grenadier, double scarlet maroon; Pike’s Pink with a crimson central zone, and La Bourbrille, a good cushion pink. All can be increased by cuttings in June.

Douglasia

Douglasia laevigata, from North America, is a good high alpine plant suitable for trough culture. It has tufted cushions of grey-green foliage in rosettes and rose-pink flowers with yellow eyes on 2-in. Stems in June. Propagate by cuttings in June.

Draba

This genus contains a number of high alpine cushion plants commonly known as the whitlow grasses and the following two from the Caucasus mountains are ideal plants for the trough. Draba bryoides imbricata makes a cushion of grey-green rosettes only 2 in. high and 6 in. wide with golden-yellow flowers in April and May. Flowering at the same time, D. rigida has a compact mat of minute green rosettes and large golden-yellow flowers on 3-in. Stems. Increase by seed in March.

Dryas

The mountain aven, Dryas octopetala, is a fine British native dwarf shrub for walls while the minor form is suitable for troughs. They are trailing plants from 1 in. high and 6 in. wide to 4m. High and 24 in. wide with oak-like green foliage. The white flowers are saucer shaped with golden stamens. Cuttings can be taken in June.

Erica

The dwarf forms of Erica carnea (herbacea) are early peat-loving heaths for the rock garden. They come from Europe and range in height from 9 to 12 in. with a spread of 18 in. They flower from December to March and all can be increased by cuttings in June. The species is flesh coloured and the following varieties are to be recommended: alba, white tinged green; Ann Sparkes, yellow-bronze, reddish-tipped foliage, carmine-red flowers; atrorubra, carmine red; James Backhouse, pale pink; Loughrigg, pale purple; praecox rubra, deep red, and Springwood White, white.

Erigeron

The fleabanes are charming dwarf compact plants with daisy-like flowers and they are small enough for a trough garden. Erigeron simplex from North America makes a tufted plant with ash-grey hairy foliage. The lavender flowers have golden centres and appear on 4-in, stems over a long period from May. Increase by seed sown in March.

Erinus

Once introduced, Erinus alpinus, a European species, will seed itself in cracks and crevices, either in sun or shade. It forms small compact rosettes of glossy green foliage and has sprays of lilac-purple flowers on 3-in, stems in May and June. Of the three good varieties albus is pure white; carmineus is carmine, and Dr Hanele is deep carmine.

Euryops

A small genus of shrubs, the one noted here being an extremely decorative evergreen from South Africa. Euryops acraeus is an erect-stemmed plant about 9 in. high and 15 in. wide with silver-grey foliage. The large golden-yellow flowers are prominent in June. Cuttings in July are a ready means of increase.

Gaultheria

This is a genus of evergreen lime-hating shrubs of which the following are useful with charming flowers and brightly coloured fruits. They grow from 3 to 9 in. high and can be propagated by cuttings in June. Gaultheria adenothrix, from Japan, is an excellent small shrub for a half shady position in a peaty medium. It has thick oval glossy green leaves and white-flushedpink, urn-shaped flowers in June which are followed by red fruits in October.

The species procumbens makes a tufted shrub spreading to 30 in. with oval glossy green leaves, pinkish-white flowers in May and scarlet fruits in October. It comes from North America.

G. trichophylla, from west China, grows 3 in. tall with oval deep green foliage and bell-shaped, pinkish-white flowers in May and rounded lapis-lazuli fruit in September.

Gentiana

Space only allows me to mention a few of this large race of gentians with a wide global distribution and the ones noted here should present little difficulty with regards to cultivation. Gentiana acaulis, a native of Europe, is about 3 in. high with large tubular deep blue trumpets over tufts of bright green foliage in early spring. Although easy to grow, it can be temperamental in flowering.

G. farreri, from west China, is 4 in. high and bears radiating laterals with narrow green foliage. The August flowers are Cambridge-blue trumpets striped violet. It requires a lime-free leafy medium. G. septemfida is an easy species from south west Asia, about 9 in. high, with straggling leafy stems and terminal clusters of bright blue trumpets in July and August.

G. sino-drnata grows up to 6 in. high with prostrate stems and narrow bright green foliage. The flowers are deep royal blue from September to December. A native of west China, it needs an acid soil composed mainly of leafmould. G. verna, the spring gentian from Europe and Asia, is about 2 in. high with tufts of green leaves and erect flowers of deep azure blue in April and May. Seed sown in March is the best method of increase, division in March for sino-ornata.

Geranium

The crane’s bills are good easy plants for the rock garden. They grow to 6 in. high with a spread of 10 in. They can be propagated by seed in March or division in April. Geranium argenteum, from the Alps, has large pink flowers with deeper veinings during June to August over much cut silver leaves. Ballerina is a hybrid with lobed ash-grey leaves and large flowers of blue purple with reddish veinings and a basal blotch of red purple from June to

September. G. sanguineum is a native of Europe including Britain with lobed green leaves and magenta-crimson flowers from May to October. The variety lancastriense is smaller with rose-pink flowers which have purple veinings.

Geum

Geum borisii is a natural hybrid from Bulgaria with roundish lobed, rough, textured, bright green leaves and large orange-scarlet flowers from May to September. It is about 9 to 12 in. high. Divide in March.

Gypsophila

The gauze flowers are good plants to use as ground cover over bulbs in the rock garden. They can be propagated by division in April or seed in March. Gypsophila cerastioides is a native of the Himalayas and it makes a mat of tufted green leaves and has clusters of white red-veined flowers on 3-in, stems in May and June.

G. repens fratensis has narrow grey-green leaves and clusters of pink flowers on 9-in, stems in June and July. It comes from south east Europe.

Hebe

This is a wholly Australasian genus and there are a large number of dwarf evergreen shrubs for the rock garden but space forbids the mention of more than just a few.

Hebe buchananii is a compact much branched shrub from 3 to 6 in. high with thick oval dull green leaves and spikes of white flowers in June and July. The variety nana is smaller in all its parts and is suitable for troughs. Carl Teschner is a garden hybrid with procumbent purple stems, oval glossy leaves and 6-in, spikes of violet flowers in June.

H. pinguifolia pagei is a garden form, up to 12 in. high and 24 in. wide, with oval leaves and clusters of white flowers with purple anthers in June. All propagate from cuttings taken in July.

Helianthemum

The following forms of the sun rose, Helianthemum nummularium, are all about 6 in. high and have a spread of 24 in. They make good plants for walls after the spring-flowering plants have finished. They should be cut back hard after flowering and increased by cuttings in July. The species is a native of Europe and it has trailing stems with oval leaves and clusters of yellow flowers. Good varieties include Amy Baring, bright orange; Apricot, apricot with a deeper eye; Ben Heckla,

brick red; Ben Lawers, deep crimson; coccineum, double, deep red; Golden Queen, golden yellow; Jock Scott, light rose; Rose of Leeswood, double, light pink, and The Bride, grey leaves, white flowers.

Hyacinthus

Hyacinthus azureus is a charming dwarf hyacinth from Asia Minor with azure-blue flowers in a tight cluster on 3-in. Stems in April. The variety albus is white. Propagate by seed in March or division in June.

Hypericum

There are a number of St John’s worts suitable for the rock garden and all are extremely free flowering. Hypericum empetrifolium is an evergreen shrublet from Greece with slender stems and narrow, grey-green leaves. The pale yellow flowers are borne on 6-in, stems during July and August.

H. nummularium is a European species which grows about 6 in. high with coppery-red young stems and rounded leaves. Like empetrifolium, it is summer flowering with golden-yellow flowers on 6-in. Stems. H. reptans, a sub-shrub from the Himalayas with oval green leaves, is only 3 in. high but it spreads to 18 in. The summer flowers are red in bud but they open to golden yellow. Propagation of all is by cuttings in June or by division in spring.

Iberis

Iberis sempervirens Little Gem is characteristic of the candytufts with dwarf erect 4-in, stems and crowded oblong dark green leaves. The white flowers in large tight heads appear during May and June. Increase by cuttings in June.

Ilex

Ilex crenata Golden Gem is a miniature holly forming a low rounded bush with yellow-green leaves which turn deeper in the winter. After many years it will attain a height of only 12 in. and is therefore a good subject for trough culture. Propagation is by cuttings in June.

Iris

Of the bulbous irises, both Iris reticulata and its forms are suitable for the rock garden. I. Reticulata has deep violet-purple flowers on 9-in, stems during February and its varieties include Cantab, Cambridge Blue; Royal Blue, deep blue, and Hercules, purplish red.

I. pumila, from Asia Minor, resembles a miniature flag iris with purple bearded flowers on 6 to 9-in, stems during April. Amber Queen is amber yellow; azurea, pale blue; cyanea, dwarf, purple; gracilis, lavender pink, and The Bride, white. Divide in June.

Leontopodium

Leontopodium alpinum is the eidelweiss with all its romantic associations. It has lance-shaped, grey-green leaves and the flowers are clustered and enveloped by a circle of thick strap-like woolly bracts. It grows to 8 in. tall and flowers in June and July. Sow seed in March.

Lewisia

The plants in this completely American genus are commonly known as the bitter roots. They are especially attractive when planted on walls. Lewisia cotyledon is distinguished by having large rosettes of thick strap-like pale green evergreen leaves with brown markings. The large flowers are salmon, veined pink and they are to be seen in June and July on 9-in. Stems. The variety finchii is pale pink with deeper veinings; howellii is deep rose veined salmon pink, and Weald Rose is cherry pink with deeper veins.

L. nevadensis is a herbaceous plant with narrow fleshy green leaves in rosettes. It has large white flowers on 2-in, stems during May and is suitable for trough culture. Increase by seed in March.

Linaria

The alpine toadflax, Linaria alpina, is a close tufted plant only 2 in. high with whorls of grey-green leaves. The summer flowers of the species are violet with an orange lip but the variety alba is all white, and rosea is pink with a golden-yellow lip. Sow seed in March or divide in June.

Lithospermum

The garden forms of Lithospermum diffusum are colourful late flowering plants for the lime-free rock garden. They grow about 6 in. high and 20 in. wide and should be cut back after flowering. Grace Ward has mats of hairy green foliage and gentian-blue flowers, and Heavenly Blue is a deep rich blue with a reddish tinge. Both these excellent varieties will flower from June to October. Cuttings can be struck in June.

Mimulus

The musks or monkey flowers prefer a cool moist root run and are good waterside plants for the rock pool. Mimulus cupreus is too rampant for most gardens but its forms are less invasive. Of these Bee’s Dazzler is deep red; Dainty, creamy yellow; Red Emperor, crimson scarlet, and Whitecroft’s Scarlet, deep scarlet. All are 6 to 9 in. high and they flower from June to August.

M. primuloides, from west America, forms a carpet of rosettes of bright green leaves only 1 in. high and the flowers which come from June to August are yellow with red-brown spots. Divide in April.

Morisia

Morisia monantha (hypogaea), the Mediterranean cress from Corsica, forms small rosettes of cut, deep green foliage only1 in. high. The flowers are stemless and golden yellow and come during May and June. Seed can be sown in March.

Narcissus

The dwarf species of the daffodil are ideal plants for both rock garden and troughs. Narcissus asturiensis (minimus) is a miniature daffodil from Spain. It is only 3 in. high with golden-yellow flowers in February and March. N. bulbocodium has the descriptive common name of the hoop petticoat daffodil. It is a native of the South of France and Spain and has a narrow funnel trumpet and small petals on 6-in, stems in March and April. The type is bright yellow and of the varieties citrinus is lemon yellow; conspicuus, deep yellow, tinged green on the reverse, and nivalis, orange yellow. Sow seed in March or divide in August.

Omphalodes

Omphalodes luciliae is an evergreen sub shrub from Asia Minor. It has tufts of light grey oval leaves and grows about 6 in. high. The flowers, which are pink in bud, open to china blue during May to September. O. verna, the blue-eyed mary, is a herbaceous perennial with tufts of light green leaves up to 6 in. high. During the spring, it bears bright blue flowers which have a white eye. A native of southern Europe, it prefers shade. June is the month for taking cuttings.

Oxalis

Avoid Oxalis corniculata and O. repens for once these wood sorrels have been introduced they are impossible to eradicate. However, the following two species are both suitable for trough culture. O. enneaphylla, from the Falkland Islands, has fan-shaped, silver-grey, red-brown edged leaves. The flowers are white with a pale yellow-green throat on 1 to 3-in. Stems from May to August. The variety minuta is smaller with yellow-eyed pink

Voir-

flowers, and rosea has pink-flushed flowers.

The Chilean O. lobata has lobed green leaves and golden-yellow flowers on 3-in. Stems in early autumn. Divide in June.

Papaver

A good poppy for the rock garden comes from the Pyrenees. It is Papaver rhaeticum which has divided light green leaves and bright orange flowers on 6-in, stems in early summer. This poppy will seed itself in most gardens.

Paronychia

Paronychia argentea makes a mat of silver-grey evergreen leaves only 2 in. high. Its minute July flowers have conspicuous white bracts. It provides an excellent ground cover for bulbs especially in troughs. The plants can be divided in March.

Penstemon

The beard tongues are all native to America and they are ideal evergreen sub-shrubs for the rock garden. All can be increased by cuttings in June. Penstemon menziesii microphyllus is a dwarf shrub, only 3m, high, with oval toothed green leaves and light purple, tubular flowers in June and July. P. pinifolius is a lax shrublet with needle-shaped leaves, about 6 in. high. The clustered flowers, during the summer months, are tubular in shape and mandarin red in colour.

P. rupicola will be found in most catalogues under the name P. roezlii. It is a prostrate plant, 4 in. high, with grey-green leaves and large tubular crimson flowers in June.

Pernettya

Pernettya tasmanica is an evergreen sub-shrub with green oval leaves. As its name implies it hails from Tasmania and grows about 2 in. high. It has white, urn-shaped flowers in May followed by red fruits in September. It requires a lime-free leafy soil in some shade. Take cuttings in June.

Phlox

This genus from America provides a good follow on to the flowering season after the spring flowers are over. They make good wall plants and should be cut back after flowering. Phlox douglasii is a prostrate plant with narrow green leaves. It is about 2 in. high with an expected spread of 15 in. and the clustered, bright pink flowers appear in May and June.

Good varieties include alba, white; Booth-man’s Variety, mauve, deeper at the base; Eva, bright pink, deeper at the base, and Violet Queen, violet. All prefer some shade in hot gardens.

The moss phlox, P. subulata, has narrow light to deep green foliage and grows from 4 to 6 in. high and up to 18 in. wide. The flowers of the species are lavender to purple with a darker central zone in late spring and early summer In the varieties alba is white; aldboroughensis, deep red; atropurpurea, deep red; Brightness, bright pink; camlaensis, large, salmon; lilacina, light blue; Temiscaming, glowing magenta crimson, and Vivid, salmon pink with a crimson eye. Take cuttings in June.

Pieris

Pieris japonica variegata is a slow-growing erect shrub about 15 in. high and 18 in. wide with oblong yellow-green margined white evergreen foliage. The white urn-shaped flowers are abundant in April. It requires a lime-free shady spot and can be propagated by cuttings in June.

Polygala

Polygala chamaebuxus is a dwarf shrub with dull green foliage, about 6 in. high and 12 in. wide from Europe. This milk-wort has pea-like fragrant flowers which have a white keel and bright yellow mouth in May. Take cuttings in June.

Potentilla

Among the cinquefoils which can be recommended for the rock garden is Potentilla curviseta from the Himalayas. It is a mat-forming plant, 2 in. high, with palmate bright green leaves and golden-yellow flowers from June to September. P. tonguei is a hybrid with much cut palmate green leaves and orange-yellow summer flowers which become crimson at the base. It is 6 in. high and 9 in. wide and can be divided in April.

Primula

In such a vast family, it is difficult to choose only a few primulas but the following are representative. Primula denticulata from the Himalayas has round heads of deep lilac flowers before the leaves in March. It, and the following varieties, grows to about 9 in. tall. Alba is white; Prichard’s Variety is deep ruby red, and rosea is rosy lavender.

P. juliana is the collective name given to the hybrids of P. juliae. All are evergreen and about 6 in. tall, flowering from March to May. Alba is white; Betty Green, crimson; Blue Horizon, sky blue; crispii, wine red; Dorothy, sulphur yellow;

Gloria, crimson, golden eye; Jewel, crimson purple; Sunset Glow, tangerine red, and Wanda, claret coloured.

P. marginata originates from the Maritime Alps. It has silvery-margined, much cut, leafy, evergreen rosettes and lavender fragrant flowers on 6-in, stems during May and June. Good forms include alba, yellow-green, silver-margined leaves, white flowers; caerulea, light blue; Drake’s Form, deep lavender; Linda Pope, lavender blue; Prichard’s Variety, bright lavender blue, and rubra, ruby red.

The hybrids known by the collective name of P. pubescens have rosettes of toothed foliage. The flowers cover a colour range of pink to violet and crimson with a white eye and are borne on 6-in, stems in May and June. Alba is white; Christine, old rose; Faldonside, deep crimson; Jane, pale blue; Moonlight, pale yellow; Cardinal, rich velvety red, and The General, brick red.

P. rosea is a species from the Himalayas. It is a good plant for a cool moist spot with rosettes of oval crinkled leaves. The flowers are dark rich rose with a yellow eye on 6-in, stems during March and April. Most can be increased by cuttings in July or division in August.

Ptilotrichum

Ptilotrichum spinosum, from Spain, makes an erect rounded 6-in, shrub with silver-grey leaves. The adult wood is very spiny. The crowded flowers of the species are white, those of the variety roseum are pink. Both appear in June and July and seed can be collected and sown in August.

Pulsatilla

Pulsatilla vernalis has the descriptive common name of the lady of the snows. It has much cut, bronzy-green foliage, about 4 in. high. The flowers which unfold in April and May from furry bronze-violet buds are glistening white backed with violet and gold and crowned by a high central boss of yellow stamens.

P. vulgaris is the pasque flower with much cut green leaves. The shaggy haired buds open to reveal rich purple flowers with golden-yellow stamens in April and May. It will grow to 6 to 12 in. as do alba, white; rosea, rose pink, and rubra, deep red purple. Increase by seed sown in July.

Ramonda

The rosette mullein, Ramonda myconi, hails from the Pyrenees. It is about 4 in. high with rosettes of rough red-haired oval green foliage. The large rounded flowers are lavender blue with a yellow eye in May and June. Of the varieties the

inevitable alba is white, rosea, deep pink.

September is the month for sowing seed.

Ranunculus

This family contains the buttercups and Ranunculus alpestris, a native of Europe, has rosettes of grey-green, three-lobed leaves. The large flowers are white with golden stamens and are borne on 4-in. Stems in May and June. It likes a moist soil and is a good trough plant. Propagate by seed in March.

Raoulia

Raoulia hookeri (australis), from New Zealand, is only fin. In height. It has minute, silver-grey foliage and stemless yellow flowers during the summer It will look most attractive when planted in a trough. Divide in July.

Rhodohypoxis

A South African species, Rhodohypoxis baurii, produces tufts of silky haired channelled green leaves and rose-red flowers in May on 3-in. Stems. Recommended varieties include Eva, deep red; The Major, deep pink; Margaret Rose, bright pink, and Ruth, large, white. Divide after flowering.

Salix

The miniature willows are ideal deciduous shrubs for the rock garden in a moist spot. Salix boydii is an erect tree-like shrub with a bole which will reach up to 18 in. in time. The grey-white leaves provide an effective background for the silky light yellow May catkins. It is a native of Scotland.

S. reticulata is a dwarf shrublet of only 2 in. high from Europe. It has deep green veined leaves and oval yellow catkins in April. Cuttings can be taken in June.

Saponaria

Saponaria Bressingham Hybrid is a soapwort with reddish stems, narrow green leaves and deep pink flowers with a red calyx in May and June. It is about 2 in. high and can be increased by cuttings after flowering.

S. ocymoides, a species from the Alps and Jura mountains, forms a trailing carpet of bright green oval leaves and bright pink flowers with red-purple calyces in May. It has a white variety alba.

Saxifraga

From such a mighty family it is difficult to choose a few for inclusion here. To conserve space, therefore, I have placed the rockfoils in sections according to their cultural requirements. All can be increased by cuttings, best taken in June. Mossy Section These require a cool, semi-shady position and they make loose carpets of light to deep green rosettes from 18 to 24 in. across. The flowers appear in May and June on 4 to 6-in. Stems. Cambria Jewel, rich pink; Darlington Double, double, deep pink; Dubarry, crimson; Flowers of Sulphur, pale yellow; James Bremner, white; Peter Pan, crimson; rosacea (decipiens) grandiflora, large, rose. Encrusted Section A position in full sun suits these best and they make small to large rosettes of silver, lime-encrusted leaves. They flower in late spring and early summer. Saxifraga aizoon is white speckled red from Lombardy and its variety lutea is lemon yellow and rosea is pink. S. cochlearis is white from the Alps; cotyledon has huge rosettes and large spires of white flowers; longifolia Tumbling Waters has a spire of white flowers 2 ft. in length while valdensis is minute with white flowers on red stems.

Kabschia-Engleria Section These make spiny cushions or rosettes of silver-grey to green leaves, 3 to 8 in. wide and require shelter from hot sunshine in summer. They flower in spring on 1 to 3-in. Stems. S. apiculata, pale yellow; burseriana Gloria, white, red stems; b. sulphurea, pale yellow; Christine, cherry red; Cranborne, rose; elizabethae, yellow; grisebachii Wisley Variety, the best Engleria, silver rosettes, crimson woolly spikes; haagii, golden yellow; jenkinsae, deep pink; prosenii, reddish orange; Riverslea, purple rose; stribrnyi, pink, in woolly purple calyces.

Sedum

The following is a short list of the many stonecrops which make fleshy stems and leaves of varying colour and form. They range in height from 1 to 4 in. and flower from May to July. All propagate easily by division in June.

Sedum album Coral Carpet has reddish-purple leaves and pink star flowers; anglicum minus, grey-green tipped red leaves and rose-coloured flowers; caulicola, rounded, fleshy, green margined, red leaves, deep purple flowers, from Japan; dasyphyllum, fleshy oval pinkish-grey leaves, white flowers; ewersii, oval glaucous-blue leaves with red margins and pink flowers, from the Himalayas; lydium, green turning scarlet leaves, white flowers; spathulifolium Cappa Blanca, greyish-white leaves and yellow flowers, from South Oregon, and spurium atropurpureum, deep reddish-brown leaves and pink flowers.

Sempervivum

This is a large family and the houseleek owes its popularity to the different colours and forms of the rosettes varying in height from 3 to 6 in. and flowering in June and July. The flowers are mostly indifferent. Increase is by division in May.

Sempervivum arachnoideum, from Europe, has green rosettes covered with spider-web hairs. Its variety, stansfieldii, has rosettes which turn red. S. arenarium has green tipped red rosettes and yellow flowers. It comes from the eastern Alps. S. ci/iosum, from Bulgaria, has grey-green, hair-covered rosettes and yellow flowers. In the species giuseppii the green rosettes are tipped brown and they are hairy in the centre. The flowers are rosy red and it comes from northern Spain.

Deep reddish-brown rosettes which turn red in winter and red flowers are the attributes of S. marmoreum from Bulgaria. S. reginae-amaliae has green rosettes tinged purple and red flowers. It comes from Greece.

Silene

The catchfly or campion, Silene acaulis, makes a cushion of small narrow leaves only 2 in. high and 6 in. wide. The flowers are pink with a reddish-purple calyx in May and June. It is a native of Europe whereas its variety exscapa comes from the Pyrenees and it is lighter green with similar flowers. Divide in March.

Thymus

The thymes are well represented by the many forms of Thymus serpyllum. The majority are intensely aromatic and are useful plants for planting in paving or in a dry wall. The species is a native of Europe and makes a rambling plant with narrow leaves from 1 to 3 ½ in high and up to 2 ½ in. wide. It has semi-hemispheres of purple flowers throughout the summer months. Its varieties include albus, white; Anne Hall, clear pink; aureus, golden-green leaves in winter, deep lilac flowers; citriodorus, lemon-scented leaves, lilac flowers; c. argenteus, leaves green and white; carmineus, carmine; coccineus, crimson, and Silver Queen, variegated leaves of silver and green. Take cuttings in June.

Trollius

Trollius pumilus, the globe flower, is a native of the Himalayas. It has five-lobed green leaves, up to 6 in. high, and many petalled bright yellow flowers in June. It is a good plant for a cool moist spot and it is easily increased by seed sown in March.

Tulipa

The small tulip species are ideal for mass planting in troughs or other containers where they can be left undisturbed. They range from 4 to 8 in. high and flower from April to June. The bulbs can be lifted and divided in August or seed can be sown in March. I would recommend the following species: aucheriana, pale rose, bronze basal blotch, Persia; batalinii, creamy yellow, greenish-yellow blotch, Turkestan; billora, outer crimson and green, inner white, yellow base, Caucasus; clusiana, white, cherry-red bands, basal red blotch, Persia; eichleri, bright scarlet, black blotch, outside striped silver grey, Asia Minor; kaufmanniana, light creamy yellow flushed rose, central Asia. There are many forms of this tulip, all are good.

The list continues with linifolia, bright scarlet, black blotch, central Asia; pulchella, crimson, black blotch, Asia Minor; tarda, bright yellow, white tipped, Turkestan, and violacea, violet blue, bluish-green blotch, Persia.

Veronica

Veronica gentianoides is a compact tufted speedwell from the Caucasus with oval green leaves and spires of pale blue flowers on 6 to 12-in, stems in May and June. Its varieties include variegata, leaves variegated and nana, a reduced form. V. spicata nana makes a compact plant only 6 in. high with green rounded leaves and violet-blue flowers in June and July. Propagation is by division in April.

Sorry, comments are closed for this post.