Ground Cover Plants
One of the most effective and labour-saving ways of controlling weeds is by means of ground cover plants. They are particularly useful for this purpose as an underplanting toand other shrubs, in borders and on sloping banks. They require little or no maintenance beyond the occasional cutting back of the more rampant types.
You cannot expect ground cover plants to smother established perennial weeds. For this reason, it is most important to prepare the ground as thoroughly as possible before planting, forking over theand removing all perennial weeds and their roots. This job will be amply repaid by the reduction in the need for weeding later. On poor soils, or in old, neglected gardens, it is a good idea to add manure, compost or fertilizer to the soil to get the plants off to a good start.
The time taken for ground cover plants to establish a weed-smothering carpet will vary according to the subject chosen. Most of those listed below will be doing their appointed job by the end of their second season. Some, like the Variegated Deadnettle, will have made a dense overall carpet by the end of their first season. Until this happens, normal weeding of annual weeds must be carried out.
Using ground cover plants cannot work instant miracles, but it can eventually cut down the task of weeding to negligible proportions. The list shows the situations in which the various plants will thrive, but for dense shade under trees I would recommend one of the vigorous spreading shrubs such as the Rose of Sharon,, or the Snowberry, Symphoricarpos albus.
In the rock garden you could use creeping perennials of mat-like growth to keep areas free from weeds. Choose for this purpose the less vigorous and invasive kinds of ground cover plants to avoid a complete takeover of the choicer alpines. The smaller polygonums, the lungworts, and the colourful rock phlox and rock pinks are all ideal for this purpose.
List of Ground Cover Plants
The figures immediately after the name of each plant give its approximate height and spread after 2 to 3 seasons.
Key to abbreviations:
D – Deciduous
P – Perennial
E – Evergreen
S – Shrub
Ajuga reptans – Bugle (DP)
10x90cm (4in x 3ft) These are low-growing plants with a rapid rate of spread, closely related to our native wild bugle. They bear upright spikes of gentian bluein late spring. ‘Atropurpurea’, with handsome coppery coloured foliage, is the most vigorous form. ‘Variegata’, with cream and grey-green leaves, and ‘Tricolor’, whose copper and purple leaves are blotched with cream, are less rampant and suitable for the rock garden. Soil – any. Sun or shade.
Alchemilla mollis – Lady’s Mantle (DP)
60x30cm (2 x1 ft) This is a plant of great beauty with attractive silken-textured, rounded pale green leaves and dainty sprays of lime-green flowers much prized by arrangers. Alchemilla associates particularly well with roses. It spreads rapidly by means of self-sown seed. Soil – any. Sun.
Anaphalis triplinervis (DP)
30x30cm (1 x 1 ft)
This is a silver-leaved herbaceous plant that forms dense spreading mats, bearing clusters of small white ‘everlasting’ flowers in late summer.
Soil – any. Sun.
Formerly known as megaseas, these members of the saxifrage family have large rounded or spoon-shaped ever-green leaves. In some forms, these turn a vivid crimson colour in winter. Cultivars such as ‘Ballawley Hybrid’ (also known as ‘Delbees’), with magenta flowers; ‘Evening Glow’, with rose-red flowers; and ‘Silver Light’ (’Silberlicht’), with white flowers, are all superior to the type. Soil – any. Sun or part shade
Various heights and spreads.
Several of the cotoneaster species are of a prostrate creeping habit, covering the ground with a dense mat of leaves and wiry stems. Among the best of this type are C. adpressus, a dwarf spreading shrub with scarlet fruits and crimson autumn foliage; C. dammeri, with longer trailing stems and masses of red berries in autumn and early winter; and C. microphyllus, a dwarf small-leaved shrub with larger red fruits than most other kinds. Two more, useful for covering banks or old tree stumps, are the Fishbone Cotoneaster, C. horizontalis, so named because of the herringbone structure of its branches, and C. salicifolius, the Willow-leaved Cotoneaster. Both of these carry abundant crops of small scarlet berries from autumn until the New Year. The leaves of the former variety turn a brilliant shade of red in autumn. Soil – any. Sun or part shade
Epimedium – Barrenwort (DP)
30x30cm (lx1ft) The barrenworts, with their preference for light shade, make attractive ground cover underneath rhododendrons and other shade-tolerant shrubs. The dainty sprays of minute columbine-type flowers add to the attraction of their delicate foliage in early spring. ‘Rose Queen’ has its leaves tinged with copper, and rosy-purple flowers. Soil – any. Part shade
Euonytnus fortune – Trailing plant (ES)
This attractive evergreen shrub is a relative of our native spindle tree. The variety radicans is the one most widely grown as ground cover. Good named cultivars include ‘Silver Queen’, whose leaves are edged with white, and ‘Variegatus’, with grey-green leaves margined with white and tinged with pink. All of these are useful plants for chalk soils. Soil – any, including chalk Sun or part shade
Heathers: Erica and Calluna (ES)
Various heights and spreads.
There can be few more effective or decorative ground cover plants than the cultivated forms of heather and ling. Once they are established, usually by their third season, none but the most persistent weeds can find a foothold under their dense mat of wiry stems and close carpet of foliage.
Heathers, too are among the most useful garden all-rounders. By choosing suitable species and varieties, you can have a display of flowers in every month of the year, including December and January. Nothing paints a more colourful garden picture in winter than the Winter Heath, Erica cornea, which blooms from January to March. In summer, a similar effect is obtained from our native Ling, Calluna vulgaris, the Dorset Heath, £. ciliaris and the Bell Heather, E. cinerea, which will provide a display lasting from June to November. The gap between autumn and winter can be bridged by early-flowering cultivars of E. carnea, such as ‘Eileen Porter’ and ‘Winter Beauty’.
Heathers do best in a sunny situation and light, well-drained soils. Heavier soils should be lightened by the addition of quantities of peat or leafmould. Heathers should be planted 40-60 cm (15-24 in) apart to form a continuous carpet. They look most effective planted in groups of three or more of a kind.
Most of the summer-flowering heathers are lime-haters and need a slightly acid soil. Of them, only the Cornish Heath, Erica vagans, is tolerant of lime. The Winter Heath, E. cornea, will tolerate a moderately alkaline soil and would be the best choice for most gardens. Varieties grown for their coloured foliage, such as ‘Golden Drop’ or ‘Aurea’, must have a position in full sun if the colouring is to develop to the full.
Lime tolerant: Erica vagans cultivars: ‘Diana Hornibrook’ with coral-pink flowers; ‘Mrs. D. F. Maxwell’, pink; and ‘St. Keverne’, lilac pink. Lime haters: Cal-luna vulgaris cultivars: ‘H. E. Beale’, silver-pink; ‘Peter Sparks’, pink; ‘Ruth Sparks’, white, all with double flowers. Erica cinerea cultivars; ‘Alba’, white; ‘Anne Berry’, with pink flowers and golden foliage; ‘CD. Eason’, vivid crimson.
WINTER-FLOWERING HEATHS (all lime tolerant)
Erica carnea cultivars: ‘James Backhouse’, pale pink; ‘Ruby Glow’, rosy crimson; ‘Springwood Pink’ and ‘Springwood White’; ‘Vivelli’, deep crimson with copper foliage; and ‘December Red’, deep rose-pink. Erica darleyensis cultivars: ‘Arthur Johnson’, magenta; ‘W. T. Ratcliffe’, white with dark green foliage.
Hedera Ivy (ES)
Normally, we think of ivies asbut many of them perform an equally useful function as ground cover plants. They form dense, weed-suppressing mats and are par-ticularly useful for shady beds.
One of the best and most vigorous kinds is the Common Ivy, Hedera helix, in its many varied forms. Some of the showier cultivars are ‘Buttercup’, with golden foliage; ‘Glacier’, whose leaves are silver-grey, edged with white; ‘Goldheart’, a striking ivy whose emerald green leaves are splashed with yellow; and ‘Tricolor’, whose grey-green and white leaves take on a pink flush in winter.
H. colchica, the Persian Ivy, has much larger leaves than those of H. helix. They measure up to 20 cm (8 in) in length in some forms. This species, too, includes cultivars with strikingly variegated leaves, such as ‘Dentata Variegata’, with bright green and cream foliage, and ‘Paddy’s Pride’, which has deep green leaves beautifully marked with bold yellow. Soil – any. Sun or shade
Helianthemum – Sun Rose (ES)
20x60cm (8in x2ft) The sun roses (sometimes misnamed ‘rock roses’) make first-class cover for the rock garden or for the fronts of. Their low, trailing growth will soon carpet large areas. The plants are covered in bloom over a long period during early summer. After they have finished flowering, sun roses should be lightly trimmed with a pair of shears. Some of the best kinds for ground cover are ‘Ben Hope’, with orange-red flowers; ‘Ben More’, orange; ‘Rhodanthe Carneum’, pink; ‘St. John’s College’, yellow; and ‘The Bride’, which has cream-white flowers with yellow centres.
Soil – light, well drained. Sun.
Hosta – Plantain Lily (DP)
Various heights and spreads.
Hostas are handsome foliage plants with broad, deeply-ribbed, plantain-like leaves and attractive white or pale mauve flower spikes that appear around midsummer. Their dense clumps of foliage will keep all kinds of weed in check. Among the best forms are H. albomarginata, which has pale green leaves edged with cream; ‘Thomas Hogg’, one of the best named cultivars and similar to the former variety; H. crispula, whose fluted dark green leaves are margined with cream; and H. sieboldiana, a magnificent plant, with leaves as much as 60 cm (2 ft) long and 30 cm (1 ft) in width and of a blue-green colour. The latter is sometimes referred to as H. glauca. Soil – fairly moist Sun or part shade
calycinum – Rose of Sharon (ES)
30 cm (1 ft), spreading.
This dwarf evergreen member of the St. John’s Wort family is one of the finest ground cover plants for dense shade and poor soils. It makes an ideal choice for clothing shady banks and similar situations where few other plants can be grown successfully. The golden flowers, each with its central boss of stamens, resemble those of a single-flowered rose and are open during June and July. The
Rose of Sharon increases rapidly by means of underground suckers and will soon cover a large area. Soil – any. Sun or shade.
Lamium – Cultivated Deadnettle (DP)
30 cm (1 ft), spreading
There are several garden forms of the wild deadnettle that make effective ground cover plants. The most rampant is Lamium galeobdolon ‘Variegatum’, whose leaves are attractively mottled with silver to provide a telling contrast to the whorls of yellow flowers in spring. This species increases rapidly by undergroundand will thrive even in dense shade. L. maculatum is much less vigorous but will perform its cover-up job well in the front of the border. The leaves are dark green with a white stripe and the flowers are purple. There is also a golden-leaved form, ‘Aureum’, but this is less vigorous than the type. Soil – any. Sun or shade
Pachysandra terminalis – Japanese Spurge (ES)
20 cm (8 in), spreading.
This is a dwarf evergreen shrub that provides excellent ground cover in moist shady situations. The thick lobed leaves are borne in rosettes at the end of the stems, and the greenish-white flowers appear in early spring. ‘Variegata’, with white-variegated leaves, is less rampant than the type. Soil – any except chalk Moist shade
Polygonum Bistort (DP)
Various heights and spreads
Several of the bistorts provide first-rate ground cover, although some are too vigorous for the average-sized garden. Two of the more restrained forms, which both form dense mats of weed-smothering foliage, are Polygonum affine ‘Darjeeling Red’, with small crimson flower spikes and leaves that turn bronze in autumn; and P. bistorta superba, a taller variety with pink flower spikes borne on tall stems from late summer to autumn. Soil – any. Sun.
Santolina – Cotton Lavender (ES)
These ‘evergrey’ dwarf shrubs, with their finely cut, silvery foliage and yellow button flowers at midsummer, make attractive ground cover for the edge of a mixed border. The two best species for this purpose are Santolina chamaecyparissus and S. neapolitana. ‘Nana’ is a delightful dwarf cultivar of the former species; ‘Edward Bowles’ is the best form of the latter.
Soil – light, well drained. Sun.
Saxifraga umbrosa – London Pride (EP)
An old cottage-garden favourite which is easy to grow and has a rapid rate of spread. It is useful in shady borders and will flourish in the poorest soils. Close-packed rosettes of dark green leathery leaves set off the dainty sprays of pale pink flowers, which appear in early summer. Soil – any. Sun or shade.
Symphoricarpos – Snowberry (DS)
1.5 m (5 ft)
The snowberries are vigorous suckering shrubs, some of which are too rampant for the average garden.
They all bear decorative white or pinkish berries that persist through the winter, since the birds leave them alone.
Symphoricarpos albus laevigatas is the Common Snowberry, with white mothball berries, ideal as cover under the dense shade of trees. More attractive and less vigorous are cultivars such as ‘Magic Berry’ and ‘Mother of Pearl’, both of which have rose pink berries. Soil – any. Sun or shade
Symphytum Comfrey (DP)
There are several species of comfrey, the best of which for rapid spread and dense cover is Symphytum grandiflorum. This species bears clusters of creamy-yellow flowers, edged with red at the bud stage, over a long period from spring to midsummer. Soil – any. Moist shade
Foam Flower (DP) 30 cm (1 ft), spreading An attractive, low-growing, creeping perennial, which bears masses of feathery white flower spikes in early summer. Tiarella cordifolia is the more vigorous species; T. wherryi can be distinguished from the former by the pinkish tinge to its flowers. The mat-forming leaves are heart-shaped and of a soft green colour. Soil – any. Partial shade