Jo Arnell explains what makes succulents such strong survivors.
Technically, a succulent is any plant with thick, fleshy (succulent) water storage organs. Succulents store water in their leaves, stems, or roots, so they can go for long periods without needing to be watered, which means that these intrepid plants manage to grow where few other plants dare.
They have adapted to arid conditions throughout the world, from Africa to the deserts of North America, eking it out in cracks and crevices, scorching sun and desiccating winds, sometimes surviving with virtually no water or soil. Now they are colonising the windowsills of student accommodation across the land, thriving in the arid air of benign neglect.
Growing Succulents outside
Succulents do grow outside in our climate and will cope with quite low temperatures – think how cold the desert gets at night, so if your garden turns into a desert over the summer, succulents may be the way to go. The reason so many are thought not to be hardy is down to our wet winters, rather than the cold. Some will grow really well outside in our climate. Apart from giant spiky yuccas, probably the most recognisable group are sedums. There will be a sedum to suit most of the dry areas in your garden – good old Sedum spectabile (often called ice plants) will even manage in dry shade. I have seen sedums in mixed borders, gravel gardens and rockeries, dry stone walls, cracks in paving and a multitude of containers – usually very shallow inhospitable looking troughs and trays.
Three years ago, I planted a species of sedum on my workshop roof – all grown from cuttings (they are so easy to propagate). I worried at first how I was going to get up on the roof to weed it regularly, but astonishingly no weeds have survived for long enough to be a problem. Conditions up there are dry and exposed and the planting medium is about only 10cm deep. The sedum is thriving.
The other group of succulent plants that are familiar are sempervivums. The name comes from the Latin ‘semper’ – meaning always, and ‘vivum’ – giving us a clue to their resilient nature. In fact, they are so tough that they were once used to plug holes in roofs – hence their other name – houseleek.
Cultivation and soil
Succulents and sedums seem to thrive on neglect, but don’t be fooled into thinking that they are completely indestructible. Kindness – in the form of water, shade and rich compost – will kill them as quickly as hot sun, poor soil and dry wind kills plants from more temperate regions. Specific potting mixes for succulents are available, but it’s easy to make your own. For my sedum roof I mixed Perlite – a granulated and very lightweight volcanic rock, with a peat-free multipurpose compost and some John Innes No:2 (a mix using soil). I tried to keep the growing medium as light as possible, but not light enough to blow away! For containers, the recommended mix is John Innes No 2 with at least 30 per cent extra grit and/or fine gravel. The important issue is drainage, so do make sure that any container has adequate holes at the base for water to escape. Do not let them sit in the wet.
Outdoor succulents will grow rapidly in the spring and early summer, often doubling in size, producing many little offsets and flowering (the flowers are quite peculiar – more suited to the set of Star Trek than the garden). Once they have flowered, they will die, making room for the offsets to take their place.
It is in the winter that succulents may need the most care and attention, as they won’t sit happily outside in damp winter conditions. Containers can be brought under cover – most will be fine somewhere sheltered outside, as long as they are kept on the dry side. If you can’t move them, perhaps try covering them with horticultural fleece, or something lightweight, over the worst of any winter weather.
Bring them out again in the spring, freshen up the compost, repot or feed (although just changing or topping up the growing medium will probably be enough), give them a water and they will burst back into life. Spring is when, in their natural environment, they would get the most water; they are primed to respond to fleeting spring rains and warming weather, to making the most of those moments before it gets too hot and dry.
Although succulents can be grown from seed, the most popular way to make more is by taking cuttings. Often this is as easy as pulling off a leaf, leaving it for a day to callous over and then poking it back into the soil. Many of them will even do the job for you, producing lots of offsets, or in the case of Aloe vera – ’pups’, which are miniature versions of the adult plant. In just a few weeks over the summer I was able to make enough new sedums to cover the whole of my workshop roof and saved a lot of money (it did take up time and space, but it was not a huge chore and the baby plants looked after themselves really well). Making plants for free is a rewarding process, but be warned, it is easy to get carried away – many a nursery business starts with a few cuttings…
Five easy succulents to grow
Sedum spurium ‘Dragons Blood’ (Stonecrop) – this is the sedum I used on my roof. It is reddish in colour (new foliage starts green), with pink/red flowers in summer, turning a deeper red in autumn. The stems are lax and it quickly spreads to make a carpet
Aloe vera – probably best as a houseplant, as it will only thrive in the warmest of summers outside. It likes to be in full sun, watered deeply occasionally. Aloes are quick to make ‘pups’ and may need repotting each spring. They can be used medicinally and apparently are great for treating minor burns – just break off a bit and gently rub it on the area as a salve.
Sempervivum arachnoideum – the ‘cobweb’ houseleek is an evergreen, rosette forming plant with a fine mesh of webbing over it – looking a bit like a spider’s web. Mature plants have pale pink flowers on long stems. Sometimes also called ‘Hen and chicks’, as the main plant is quickly surrounded by lots of little offsets, or ‘chicks.’
Echeveria secunda var. glauca – the ‘pinwheel’ succulent is another rosette forming plant, with pale green, glaucous leaves tinged with pinky-red at the edges. It is slightly less hardy than the sempervivums and benefits from being brought under cover in winter.
Aeonium ‘Cyclops’ – a tall and very striking succulent with rosettes of reddish-bronze leaves on long stems. It may get to be about a metre tall with rosettes spanning up to 40cm across. They are quite happy outdoors for the summer, but will need to be protected in colder weather and brought inside for the winter.
Visit hornbrookmanor.co.uk to find out more about the gardening workshops and courses that Jo Arnell runs throughout the year from her home in Woodchurch.
Grown on a small scale they can be used as miniature landscaping
Rosettes of Echivera
Take your pick succulents lining up for sale
Use a lightweight growing medium on a living roof
Where some plants fear to tread sedums and other succulents make a great living roof
These versatile plants can be used in many situations - here in place of a well cover
Succulents have become a popular sight at flower shows
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