High and dry! Give succulents the arid conditions they crave and you can enjoy their vibrant beauty throughout winter’s dark days, says Monty Don
The clocks go back early tomorrow morning and for the next couple of months it is as though the whole world of plants and gardens retreat into themselves. But I have a collection of succulents in the greenhouse that I go and visit on the dankest, greyest days in the sure knowledge that they will delight and enliven me, firing a shot across winter’s bows.
These are plants of the desert, of dry places scorched with sun in summer and a surprising degree of cold in winter. The greenhouse serves to protect them from the rain as much as the cold.
All succulents have evolved to cope with drought by storing moisture within their cellular structure. Many also keep their stomata – small holes in their leaves – closed during the day and only open them at night to transpire.
Monty Don shares his advice for thriving succulents as he admits visiting the plants in his greenhouse on the greyest days brings him delight. Pictured: Monty with a selection of his aeoniums
This means that many succulents thrive when there is a noticeable difference between day and night-time temperatures, which is a problem for most other plants.
Hence, they are a rare example of a plant that enjoys being on a south-facing windowsill that can become really hot during the day but cools dramatically at night.
I have a range of succulents but by far the most dominant type are aeoniums. They are native to Madeira, the Canary Islands and North Africa where they form shrubs on rocky, arid hillsides.
Q I planted some orange and lemon pips about 22 years ago and one pip grew. It has flourished and has sharp spikes, but will it ever produce fruit?
Lesley Wilcocks, Wirral
A If it has not produced fruit after 22 years, it probably never will. Lemons grown from seed can take up to 15 years to form fruit and, like yours, may never do so. Even if they do, the lemons are unlikely to be very good.
Q There are roots growing out of the bottom of the large pot that my Salvia ‘Hot Lips’ is planted in. Can I cut these off?
Susan Walker, Newport
A You can, but this is a sign it needs a larger container. Remove the salvia from the existing pot, allowing any loose compost to fall away, and repot into a container that is about 2.5cm or so larger all round, using a general purpose peat-free compost – ideally with a little grit or perlite mixed in to improve drainage.
Q My 15-year-old red ‘Crimson Cloud’ hawthorn flowered profusely this year and then died. Can I set a winter clematis to grow through it, or will the new growth be contaminated?
Honor Hadwick, Lincolnshire
A Yes, the dead wood will make an excellent support for the clematis or any other climber. When a fruit tree such as a hawthorn flowers with extra vigour or out of season, it is often a sign it’s in real trouble and is desperately trying to produce seed in order to reproduce.
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They are more or less dormant in summer and winter, the driest seasons, so can be allowed to go completely dry but they do need a weekly water in spring and autumn, which are their growing periods. If they are outside they will get all the water they need from rain, even in the driest summer.
Aeonium colours range from the deep purple of ‘Zwartkop’ or ‘Blood’ to the light green of ‘Maximus’. ‘Blushing Beauty’ has red-flushed leaves and ‘Sunburst’ is variegated with yellow and green stripes.
While most varieties are branched with a rosette of leaves on each stem, A. tabuliforme makes a flat disc of foliage that can be grown vertically as well as horizontally.
Aeoniums are not frost hardy so cannot be left outside in winter but they can be quite cool and don’t mind a little shade. It’s normal if dark leaves start to turn green or the lower ones fall off in winter or summer; they will regain their beauty once they start to grow again.
Although the rosettes of leaves are floral-looking, aeoniums’ real, star-shaped flowers emerge on a long stem.
These can last for months, but are bad news for the plant because once the flowers have set seed, the supporting growth then dies. For a flat disc like A. tabuliforme this means the end of the plant but for the branching varieties, only the stem that carried the flowers dies back.
Remove the spent flowerhead back to the main stem and the remainder of the plant will continue to grow normally.
The easiest way to propagate aeoniums is from cuttings in spring. Choose slender, young growth and cut it off flush with the main stem.
Leave these for a few days to dry and form callouses over their cut ends. Then pot them into a very gritty compost mixture with at least half the stem above soil level.
At this year’s Chelsea Flower Show Cornish nursery Surreal Succulents launched what they call x Semponium ‘Sienna’, the first cross between an aeonium and a sempervivum, another type of succulent.
As well as having vibrant russet and green colour, it is both hardier than any aeonium, down as far as -5°C, and much faster growing than a sempervivum.
MONTY’S PLANT OF THE WEEK
Monty chose V. farreri (pictured) as the plant of the week and explained that it shouldn’t be pruned for the first few years
Now in full bloom, this deliciously scented plant has pinkish-white flowers that will occasionally develop red fruits. These flowers will sometimes reappear again in mid-winter and spring.
V. farreri grows to about 3m tall and there are two variations on the basic form, ‘Candidissimum’, which has pure white flowers, and ‘Nanum’, a dwarf form that is good for smaller spaces but is more reluctant to flower.
Do not prune viburnums for their first few years; thereafter, remove a fifth of the oldest stems at the base immediately after flowering.
THIS WEEK’S JOB
SOW BROAD BEANS
Beans are usually grown after a root crop and before brassicas. Sow at 23cm spacing in double rows 45cm apart. They will grow until about 30cm tall, then stop until the days start to lengthen in February, and may need support to protect against snow or heavy rain.