How to grow and care for succulents such as sedum and sempervivum, including advice for propagation and overwintering.
Most succulents come from hot countries and they need protection over winter because they are not fully hardy. Most will survive in an unheated greenhouse if fleeced, but there are usually some losses. However, there are some hardy succulents – principally houseleeks and sedums.
What is a succulent?
‘Succulent’ covers a wide range of plants, some hardy and some decidedly tender, however they all share one characteristic: they have fleshy stems and leaves that carry water.
This makes them drought tolerant so they are ideal plants for hot, sunny positions. The water they store helps them through dry summer months, so if your watering regime is less than perfect these sculptural plants are for you.
Succulents store water because their root systems tend to be shallow, so all succulents (hardy or not) will resent cold, wet soil at their feet – especially in winter.
Many succulents have glaucous leaves arranged in a rosette. Others have tiny leaves similar to bladder rack seaweed. Some have linear leaves. Mixed together, they provide an interesting mix of textures. Spines and web-like hairs put off grazing animals in the wild but, despite this, succulents are a lot kinder on the fingers than prickly cacti.
Single specimens can look stunning grown alone, especially once they mature. Galvanised metal is an especially suitable material: it frames the greyer varieties perfectly. However there are burnished blacks, warm-golds, warm-red and variegated creams and greens on offer too.
Where to plant?
Succulents need a warm, sunny well-drained position to develop their foliage colour.
Most succulents will be grown in containers and pots and they will need good drainage. Add coarse grit to soil-less compost and repot every year in late-spring.
Don’t worry about damaging the roots when re-potting: these plants tolerate disturbance.
When summer begins to wane, begin to dry off the plants by moving them against a house wall where rain cannot penetrate the roots.
Get them as dry as you can before putting the hardy pots somewhere sheltered.
Place the tender succulents in the greenhouse with a frost-breaking heater.
Fleece them well in cold weather.
Clean any mouldy or dead leaves away regularly.
Revive them in March, with a drink.
If they look dead give them at least three months before throwing them away.
How to propagate succulents
Succulents are easy to propagate in almost all cases.
Those that produce new rosettes can have babies pulled away.
Individual leaves root easily in horticultural sand if left to for a day so that the wound calluses over. Nurseries often dry them off completely before propagating them.
Small succulents rosettes keep for many weeks and they will still grow away.
Always check for vine weevil: they adore the fleshy leaves and stems. Should you find any, bin the plant but pull off some leaves or a smaller rosettes and pot these up.
Succulents thrive on poor soil. They do not need feeding as long as they are repotted in good compost and grit every year.
Pebbles throw up heat and single specimens in pots can be made to look much better with grit or small stones round the base. This layer will deter pests.
Houseleeks, or sempervivums
Houseleeks are hardy enough to withstand British winters, although they do tend to get ragged during hard winters. They normally grow away in spring and by early summer they look handsome once again. Houseleeks spread by forming new rosettes and four or five new rosettes usually form each year giving rise to the common name Hens and Chicks. Once the rosette gets large enough, a flower spike will appear. After this, the rosette dies leaving the baby rosettes more space to grow.
Basically, sempervivums are monocarpic – they die after flowering. If a houseleek gets stressed (if it’s too hot and dry) it will flower and set seed more quickly.
Six varieties of sempervivum
There are many to choose from that are equally good.
Eye-catching vivid emerald green rosettes with black tips.
Unusual bluish purple leaves with dark tips
Medium-sized pinkish red and glowing orange rosettes
Shapely pink-brown leaves
Echeveria-like enormous dark-red rosettes
Large pale-lilac rosettes
The smaller, low-growing sedums make excellent partners for all succulents. Many are hardy, but not all.
Sedum sieboldii (Japanese orpine)
Flat waxy leaves with a red hue topped by pink starry flowers. Sprawls well – hardy.
A shrubby sedum that can reach over two foot in height, producing stems topped by green leaves margined in red. A Mexican species for a hot spot – not totally hardy.
Sedum morganiacum (Donkey’s Tail)
Hanging branches of overlapping blue-grey leaves arranged in a dense spiral. Probably Mexican. Treat as a tender.