||Ground cover plants
Ground cover plants do exactly what their name suggests – they grow along the ground, smothering weeds in their wake. They can, in an ideal situation, cover every bit of available soil so that you are hard-pressed to see the bare earth (if you can, it means that weeds can grow there too).
Ground cover plants
There is an enormous range of ground cover plants. They come in all of the common hardy plant genres; they may be herbaceous, shrubby, woody, succulent or grass-like. In addition, they may have a clumping, sprawling or vining habit, and may be evergreen (the most useful) or they can be deciduous, or somewhere in between. There are even forms that are annual, biennial
or perennial by nature.
Ground coverers are the perfect choice if you have an awkward bank of soil that is unsuitable for grassing over, either because it makes subsequent mowing dangerous or because the slope is such that the soil and grass are unstable.
They are also excellent for dryish soil in shade, such as under a tree. And they come into their own if you have a large area and little time to look after it – for these plants, in general, look after themselves.
For the most part, ground cover plants can be anywhere between 1in (2.5cm) and 4ft (1.2m) high, and you can choose from plain green types (some may say ‘boring’), to those that are excitingly colourful and vibrant.
Those discussed on the next few pages are all suitable for growing in coastal gardens, with a few even being happy along the seashore.
Aubrieta (Aubrieta spp) This hardy, evergreen perennial has masses of small, four-petalled spring flowers in shades of pink, mauve, purple, blue and white. Perfect for the rock garden, or on scree slopes or dry walls, it will survive close to the sea. There are several forms, such as ‘Hartswood Purple’. USDA Zone: Z5–8
Bistort, or knotweed (Persicaria spp) This is a huge family, which includes the famously invasive Japanese knotweed. However, there are some non-invasive forms that are ideal for coastal gardens. All are sturdy and attractive perennials with a long flowering season, such as Persicaria amplexicaulis ‘Firetail’ AGM. USDA Zone: Z4–8
Japanese spurge (Pachysandra terminalis) This plant comes close to being the ideal ground cover for a shady part of the garden. It makes a level, evergreen carpet of foliage about 8in (20cm) high. It is vigorous without being invasive, and there is a variegated form. These plants do not do well on chalky soils, however. USDA Zone: Z5
Blue flaky juniper (Juniperus squamata) This plain species is tall and not really suited to gardens, but it has produced some first-class cultivars, including ‘Blue Carpet’, a vigorous spreading plant. The outer branches have attractively nodding tips. In winter the foliage colour can be purplish, steel blue or blue green, whilst in summer it is much more silvery. USDA Zone: Z5
Broom (Genista tinctoria) This is a sun-loving, drought-tolerant plant that will positively thrive in the free-draining, sandy soil of a garden close to the shoreline. Its bright yellow pea flowers last for several weeks in early summer, and the double form, ‘Flore Pleno’ AGM, is even better. Genista lydia AGM is a low, spreading form also, but better for a rock garden. USDA Zone: Z5–9
Bugle (Ajuga reptans) A hardy perennial with creeping stems, this vigorous, plant can be a nuisance. It flowers well in summer, producing blue spikes around 6in (15cm) in height; however, the foliage is often the most important feature. ‘Burgundy Glow’ has maroon and cream leaves, ‘Braunherz’ AGM is deep purple and bronze, and ‘Variegata’ is green and cream. USDA Zone: Z6
Californian lilac (Ceanothus spp) The Ceanothus shown on page 132 is an upright form, and there are many that make tall shrubs for growing against walls. There are just as many low-growing forms that cover the ground, effectively turning it blue when they are in flower. One of the best is ‘Blue Mound’ AGM. USDA Zone: Z4–8
Canary Island ivy (Hedera canariensis) Although less often grown than the common ivy (Hedera helix), the Canary Island ivy is a more striking plant, especially in the form ‘Gloire de Marengo’ AGM. Its leaves are marbled with white, giving it lots of impact. Although it is generally regarded as a foliage climber, it will also carpet a large area of ground. USDA Zone: Z8
Cranesbill, or hardy geranium (Geranium spp) These are generally clump-forming plants, with lobed or divided green leaves, and summer flowers in shades of white, pink, purple and blue. There are hundreds of forms – all are very hardy and all are accepting of wind and salty air. The cultivar ‘Russell Prichard’ AGM freely produces deep pink flowers. USDA Zone: Z6
Dead-nettle (Lamium spp) We have already seen the silver-leaved Lamium (p142), but there are many forms and all are good ground coverers. L. orvala is arguably the species that most closely resembles the nettle (Urtica spp). This form produces clusters of pink flowers during late spring and early summer. USDA Zone: Z6
Elephant’s ears (Bergenia spp) These evergreen perennials are low, spreading plants with glossy leaves that contrast well with other foliage. They make excellent ground cover. The nodding clusters of bell-shaped flowers are most attractive in late winter and spring. Both foliage and flowers are good for cutting. USDA Zone: Z3
Thrift, or sea pink (Armeria maritima) A small, clump-forming perennial, this plant grows to about 8in (20cm) high. It produces a basal mound of narrow, grassy, dark green leaves, and in late spring and early summer it sends out spherical heads of rose-pink, pink or white flowers on stiff, slender stems. The most important thing for this plant is a free-draining soil. USDA Zone: Z4
Evergreen viburnum (Viburnum davidii AGM) The extensive use of this plant shows its versatility and appeal. It is at its best when it is still young, forming a compact mound of deep green, curiously veined leaves. Near a male pollinator, female plants produce stunning winter berries, described variously as blue-black and turquoise. USDA Zone: Z7
Lilyturf (Liriope muscari AGM) This is a tough but graceful plant. It develops a clump of narrow, grass-like, evergreen leaves about 12in (30cm) high. In autumn, plants send up slender spikes of tiny, round purple flowers that are often followed by small black berries. It seems to thrive in gardens very close to the sea. USDA Zone: Z6
Heather (i) (Calluna spp) This is a well-known ground cover plant for an acid soil. Although it flowers best in full sun, it does tolerate some shade. The flowers come in shades of white, pink, red and lilac in the summer and early autumn, and many forms have attractive winter and early spring foliage. ‘Forest Fire’ also has red tips to the young spring foliage. USDA Zone: Z4
Heather (ii) (Erica carnea) This can be very successful near the sea. It is rarely troubled by salt or wind – which just blow over the top of it. Dark green, needle-like, evergreen leaves are topped in late winter or early spring by masses of tiny, tubular flowers. Look for ‘King George’ (dark pink), ‘Myretoun Ruby’ AGM (ruby red) and ‘Springwood White’ AGM (white). USDA Zone: Z5
x Heucherella (Heucherella spp) These are hybrids between Heuchera and Tiarella – and they are thought by many to be superior plants. They are profuse and repeat bloomers, with little starry flowers on thin stems. ‘Tapestry’ has stunning, multicoloured leaves with dark centres, and warm pink flowers. USDA Zone: Z5
Houseleek (Sempervivum spp) These creeping succulents will grow across the ground, but do not grow them if you want something to smother weeds, as these are too slow and too sparse. They are highly decorative, however, and incredibly tough plants. They need so little water and nutrients that they can grow perfectly well from a pocket of soil in a stone wall. USDA Zone: Z4–8