Many plants are low-growing and spreading in habit and may be termed ground-cover, but the prime requisite of a good ground cover plant is to provide a rapid, dense cover, to suppress

Germination is the process by which a seed develops into a new plant. It starts with the seed coat absorbing water, expanding and splitting, which allows oxygen and water into the seed so its food reserves can be broken down and used by the embryo for growth. The first root (called the radicle) pushes into the soil to anchor the new plant in place and start absorbing water and nutrients. The first shoot (called the plumule) then grows upwards, out of the soil, towards the light.

Whatever ground-covering plants are used, some weed control will be necessary until the young plants have established and formed a cover (good soil fertility is therefore very important). They will also need to be kept watered during dry spells in the first season or two, especially if positioned under trees.

Suggested spacings for each plant are given below.

Mound forming and prostrate shrubs

Deciduous shrubs:
Cotoneaster horizontalis: 60cm (2ft) apart
Cytisus × kewensis 'Niki': 90cm (3ft) apart
Genista hispanica: 60cm (2ft) apart
Potentilla fruticosa ‘Manchu’: 90cm (3ft) apart. Cultivar of native to GB and Ireland.
Rosa Flower Carpet series: 90cm (3ft) apart

Evergreen shrubs:
Arctostaphylos uva-ursi: 30cm (1ft) apart, acid soils only. Cultivar of native to GB and Ireland
Berberis candidula: 90cm (3ft) apart
Calluna vulgaris and cvs.: 45–60cm (1½–2ft) apart, acid soils only. Cultivar of native to GB and Ireland
Cistus salviifolius ‘Prostratus’ (milder areas): 60cm (2ft) apart
Cotoneaster conspicuus ‘Decorus’ AGM: 60cm (2ft) apart
Cotoneaster dammeri AGM, C. salicifolius ‘Gnom’: 60cm (2ft) apart
Cotoneaster × suecicus ‘Skogholm’: 90cm–1.2m (3–4ft) apart
Erica carnea and cvs.: 45–60cm (1½–2ft) apart, acid soils only
Erica vagans and cvs.: 60cm (2ft) apart, acid soils only. Cultivar of native to GB and Ireland
Euonymus fortunei ‘Silver Queen’ AGM: 90cm (3ft) apart
Gaultheria procumbens AGM, G. mucronata: 60cm (2ft) apart, acid soils only
Helianthemum ‘Rhodanthe Carneum’ AGM, H. ‘Wisley Primrose’ AGM: 60cm (2ft) apart
Juniperus sabina ‘Tamariscifolia’, Juniperus squamata ‘Blue Carpet’ AGM: 1.2m (4ft) apart
Juniperus × pfitzeriana, J. rigida subsp. conferta: 90cm (3ft) apart
Prunus laurocerasus ‘Zabeliana’, P. laurocerasus ‘Otto Luykens’ AGM: 90cm–1.2m (3–4ft) apart
Taxus baccata ‘Repandens’ AGM: 1.5m (5ft) apart. Cultivar of native to GB and Ireland.
Rubus ‘Betty Ashburner’, R. tricolor: 45cm (1½ft) apart
Veronica pinguifolia ‘Pagei’ AGM: 45cm (1½ft) apart

Perennial plants

Herbaceous perennials:
Alchemilla mollis AGM: 45cm (1½ft) apart
Bergenia ‘Morgenröte’: 45cm (1½ft) apart
Cornus canadensis AGM: 45cm (1½ft) apart
Geranium macrorrhizum ‘Ingwersen’s Variety’ AGM: 45cm (1½ft) apart
Geranium × riversleaianum ‘Russel Prichard’: 45cm (1½ft) apart
Symphytum ibericum : 45cm (1½ft) apart

Evergreen perennials:
Epimedium perralderianum: 45cm (1½ft) apart
Persicaria affinis ‘Darjeeling Red’ AGM: 45cm (1½ft) apart
Sagina subulata: 4cm. Cultivar of native to GB and Ireland
Stachys byzantina ‘Silver Carpet’: 45cm (1½ft) apart
Waldsteinia ternata: 45cm (1½ft) apart

Creeping, suckering, spreading and thicket forming plants

Herbaceous:
Ajuga reptans ‘Caitlin’s Giant’: 45cm (1½ft) apart. Cultivar of native to GB and Ireland
Chamaemelum nobile: 25cm. Native to GB and Ireland 
Galium odoratum: 30cm (1ft) apart. Cultivar of native to GB and Ireland
Stephanandra incisa ‘Crispa’: 90cm (3ft) apart

Evergreen:
Euphorbia amygdaloides var. robbiae: Variety of native to GB and Ireland
Euphorbia amygdaloides ‘Purpurea’: 60cm (2ft) apart. Cultivar of native to GB and Ireland
Fragaria vesca ‘Semperflorens’: 45cm (1½ft) apart. Cultivar of native to GB and Ireland
Hedera colchica ‘Dentata Variegata’ AGM, H. hibernica AGM: 90cm (3ft) apart
Hedera helix ‘Glacier’ AGM: Cultivar of native to GB and Ireland
Hedera helix ‘Goldchild’ AGM: Cultivar of native to GB and Ireland 
Hypericum calycinum: 45-60cm (1½-2ft) apart
Lamium galeobdolon: Native to GB and Ireland
L. maculatum ‘Beacon Silver’: 60–90cm (2–3ft) apart
Leucothoe fontanesiana AGM: 90cm (3ft) apart, acid soils only
Lysimachia nummularia ‘Aurea’: 45cm (1½ft) apart. Cultivar of native to GB and Ireland
Mahonia aquifolium: 60–90cm (2–3ft) apart
Pachysandra terminalis AGM: 30cm (1ft) apart, acid moist soils only
Rubus ‘Betty Ashburner’, R. tricolor: 45cm (1½ft) apart
Vaccinium vitis-idaea: 60cm (2ft) apart, acid soils only. Native to GB and Ireland
Vaccinium vitis-idaea Koralle Group AGM: Cultivar of native to GB and Ireland  
Vinca minor: 60cm (2ft) apart. Archaeophyte to GB and Ireland