Sedum acre 'Goldmoss Stonecrop'

Delicate in appearance and yet very cold hardy, Sedum acre is beautiful from the first stirrings of early spring to the twilight of autumn. With golden yellow blooms and small egg-shaped, green leaves it thrives and spreads in droughty rockery edges in full sun.
In late spring and early summer, a dense mass of small bright-yellow star-shaped blossoms cover the foliage, resembling a mound of golden moss. Grow it on south-facing walls or banks, as a ground cover or as a green roof. They are at their loveliest spilling over edges of walls and rocks to create the illusion of a living waterfall.

Sedums are low maintenance, durable and interesting. They enhance the appearance of green roofs, vertical walls and rockeries due to differing leaf forms, flower colours and extended flowering period. If started early, it forms a nice dense ground cover the very first season. If the weather is favourable it will flower within six months. They are suitable for alpine gardens, ground covers, troughs and pots and successfully complement other rock-garden components.

When the flowers & stems go brown, they will linger quite some while and for tidiness sake may need to be removed. If left, the sedum will self-seed in August or September.
It will tolerate a bit of shade but prefers lots of sun if it is to bloom well. As drought-tolerant succulents they are hardy and easy to grow, requiring minimal care, only full sun and good drainage to thrive.

Sowing: January-March or June-August for flowering the following year
Seeds can be sown in spring or late summer at temperatures around 10 to18°C (50 to 65°F). Cold temperatures (10°C / 50°F) will increase the cultivation time. In spring the plants start to grow at 15 to 18°C (60 to 65°F).

Sowing Direct: For a Green Roof or Rockery
Prepare a fine weed free free-draining bed. Mixing seed with fine sand will aid even distribution. Sow seed evenly over the surface. Gently rake the seed bed so the seed comes into contact with the soil mix and gently water in. For green roofs, use a soil mix specifically for the purpose. For wintering the root development should be very good, small seedlings need to be frost free at around 3 to 5°C (37 to 41°F) so if you are growing seedlings through the winter outdoors, outdoor fleece cover will be needed to keep them frost free.

Sowing Indoors: In Pots
Sowing directly into small pots is recommended. Use seed spoons if you have them or mix the fine seeds with fine sand to aid even distribution. Fill pots with an acid-free, free-draining soil seed compost. Tap the pot to settle the compost, but do not firm the mixture down. Stand the pots in water, moisten thoroughly and drain. Seeds should be scattered very lightly over the surface.
Sedums require light for germination. Cover seed lightly with vermiculite after sowing.
If possible, place in a propagator otherwise, secure a polythene bag around the pot or cover the container with glass or and place in a warm place. Many people make use of a warm place such as the airing cupboard, or near the kitchen boiler. Care should be taken to prevent the pots drying out from below. Keep soil slightly moist but not wet. Some people stand the containers on a tray of damp sand, so that they do not dry out.
The seeds germinate best at temperatures of 18 to 22°C (65 to 72°F). Most seedlings appear within 14 to 21 days.

Be careful to keep the top of the compost damp but not wet. As soon as the first seeds have germinated, remove the plastic or raise the lid slightly to permit circulation of air.
Six to eight weeks after sowing transplant or thin out to 1 to 3 plants into a 9 to 10 cm pot or about 3 to 5 plants into an 11 to 15 cm pot. Avoid very large pots, because the substrate in pots that are too large will be permanently wet and wetness can cause growth inhibition and a poor root development.

Cultivation:
Sedum tolerates high temperature and dryness, but the roots are very sensitive to wet substrates. Plant in acid-free free-draining soil in a sheltered, sunny position.
Low to moderate fertilization levels are required. Use a complete balanced fertiliser, avoid high ammonium and high nitrogen levels. (Very high nitrogen levels in substrate cause shoot stretching and the shoots fall apart). Don't fertilize after mid September.

Plant Uses:
Beds and borders, City, Containers, Cottage/Informal, Drought Tolerant, Gravel, Ground Cover, Low Maintenance, Rock Gardens, Green Roofs.
Sedums look good in containers and in combination with other succulents such as sempervivum, echeveria or stonecrop. You can also display them with “steppables” such as mosses, ajuga, or creeping thyme.

Sedum for green roofs or vertical walls:
Green roofs generally use sedum and other alpines to provide a natural finish to a roof. Sedums are at home in poor soil and have drought-tolerant capabilities that are second to none. The plants are very hardy, and can withstand great ranges of temperature and weather.
Sedums are able to close off their pores in the presence of hot, bright sunlight, and at night, open up to put out oxygen and breathe in carbon dioxide.
The plants have roots that are between 7 to 10cm (3 to 5in) deep. They do not need mowing, weeding or deadheading. During the spring and summer they will flower and attract many insects especially bees and butterflies.

Origin:
Sedum acre is native to Europe and or West and North Asia.

Nomenclature:
The name Sedum is derived from the Latin word sedo meaning "to sit". This refers to the manner in which some species of this genus attach themselves to rocks and walls and stony ledges.
The leaves have a sharp taste, from which it gets both its species name 'acre', meaning 'sharp' and its common name 'Biting stonecrop'