Most ground cover - or other plants - take a year to get settled in - before they really start their growth cycle. This is mainly because if pot grown previously, the root system will be confined. In any event it takes time for the roots to re-establish and get accustomed to their new home!
It will take time for those roots to start to spread, and give the plant the confidence in its surrounds to start into good growth. It is mainly for this reason, that the ground that you wish to cover with ground cover plant will need to be weeded firstly.
You cannot simply plant any groundcover plant and expect them to become established themselves if they are surrounded by established weeds that have access to the nutrients in the soil.
(Listed by height and spread)
All of these plants are suitable for ground cover planting, and are capable of suppressing weeds once established. They are ideal for low maintenance planting and gardening.
The probable spread in over two years, will be at least two or three times the diameter of the plant when first planted. (Much depends upon the situation and treatment. For ground cover planting, regular feeding in the early stages is quite important to get the 'cover' functional as soon as possible. A good idea is to give the groundcover plants some localised feed by way of Osmocote pellets in the planting hole. If the ground is liable to dry out, then water gel crystals can be used as well to conserve soil moisture. After all you do want your groundcover plant to do the best job as soon as possible
Section 1 - Ground cover plants up to 15cm (6in) high. Flowers may extend more than that above the plant foliage.
Acaena - P
Aegopodium variegatum - not forgetting that it is a member of the Ground Elder family! Nonetheless a good ground cover plant. - P
Ajuga - P
Alchemilla mollis - P - Alchemilla alpinum is the shortest.
Allysum saxatile - P
Armeria (Thrift) - P
Arabis - P
Arenaria - P
Asperulea - Woodruff
Aubrieta - P
Campanula carpatica amongs others.
Cerastium - P
Clematis montana - yes - as a ground coverer.
Cotoneaster procumbens - S
Cistus - the Rock Rose Type - S
Cyclamen Coum Hybrids or Cyclamen hederifolia - good under trees o in open.
Ericas - especially the E carnea types can be kept to under 6in with annual clipping.
Hedera varieties - S of Hedera helix - S - What better?
Helianthemum - Rock Roses.
Iberis - Candytuft
Juniper horizontalis - S
Lamium - P
Lithodora diffusa - What a blue!
Lonicera japonica Halleana - no hesitation is suggesting this semi evergreen honeysuckle.
Lysimachia nummularia 'Aurea' - P
Muscari - The grape hyacinth (Bulb) will run riot and keep most weeds at bay.
Nepeta - P
Origanum Thumbles Variety is a good ground hugger
Pachysandra - P
Pholx subata - P
Pulmonaria - P
Rosmarinus prostratus - S
Saponaria caespitosa - Soapwort. Good groundcover.
Saxifrage - P
Symphytum tuberosum - P
Thymes - all thymus varieties - S
Vinca minor and Vinca major - S
Section 2 - Ground cover plants that can grow to 45cm (18in) high - Flowers may extend more than that above foliage canopy.
Artemisia - some gorgeous silver foliage in this group.
Anemone huphensis - maybe a little bit taller for the foliage.
Astilbe - good in damp or dry.
Astrantia - dense foliage - flowers held aloft.
Bergenia - Elephant's Ears.
Brachyglottis Sunshine - Senecio as was.
Crocosmias - many to choose from C sulphurea I like a lot.
Convulvulus cneorum with the silver foliage is a must for dry and sunny places.
Erythronium tuolomense or E. Pagoda or E californicum
Euonymus Emeral N Gold, Emerald Gaiety are two of the best for ground cover.
Genista Lydia Genista hispanica
Geranium macrorrhizum will cover anything - sun or light shade. As will geranium Johnson's Blue and most others.
Geum coccineum, Mrs Bradshaw etc. All are good.
Gypsophila - rockery varieties
Hebes various - subalpina, albicans and the like.
Helichrysum - The Curry Plant and others
Heuchera - various including the Coral Bells. Many new varieties - each week it seems.
Hostas - great in shade.
Houttuynia. Good but colourful rather than ground cover once established.
Lavandula - English varieties more hardy then French!
Origanum vulgare types such as O v. Herrenhausen is good
Osteospermum - Cover anything and as dry as you like.
Parahebe catarractae -
Persicaria affinis Superba
Polystychum setiferum divisilobum Group. Splendis fern ground cover.
Potentilla fruiticosa varieties
Rosmarinus - Rosemary double up as culinary herb of course. As dry as you like.
Santolina the Cotton Lavenders are superb groundcover shrubs.
Section 3 - Ground cover plants that can grow to
90cm (36in) high