We need the rain – or do we?

Exploring the prickly delights of growing outdoor cacti and succulents, some of which are much hardier than you might think

Maihuenia poeppigiiIt’s been hot out there recently. Most of the garden needs a proper drink. But some of our plants are thriving in these conditions. So, with the hot, sunny and extremely dry weather we’ve been having, I thought I would write a little about succulent plants. This group are extremely tolerant of such conditions due to adaptations in their leaves, stems or roots which allow them to store water. 

These plants can also be used to add both structural interest and flowers to troughs, pots and dry, rocky areas in the garden. Many succulents are very cold hardy. However I must stress that cold, wet conditions (like the British winter) is really not their thing and can quickly cause rotting. Some of the succulents I am going to look at will successfully survive winter outdoors, especially in the southern part of the UK; however, others need winter protection from the rain so should either be taken under cover in the winter or small ones can be potted and taken inside.

Delosperma cooperiDelosperma cooperi  This little plant is pretty tough and will generally survive a British winter if the soil is free draining. It is perfect for trailing out of a pot or trough or over a sunny wall and its mass of bright pink flowers add amazing vitality to the garden.

Agave parryi  I have brought this beautiful plant through the winter outside in a pot, but it would likely do better planted in a very free draining spot or with shelter in the winter. Agaves such as A. parryi and A. americana which survive outside do tend to suffer from water on the leaves, causing rotting and unsightly brown patches. So if you can, put them under a porch or into an unheated greenhouse. Agaves like space to grow, and therefore do well in the open ground or in a large pot, adding much architectural value. They grow big quite quickly so they are not suitable for troughs, and have vicious spines on the tips so are not the best choice if young children are running around the garden.

Echinopsis 'Susan Dace'From the Cactaceae family, plants that do well in our sand beds at Wisley include Echinopsis (try ‘Susan Dace’ (see photo, right) or ‘Ralph’s Orange’) and Echinocereus triglochidiatus var. neomexicanus. These appreciate cover in the winter and at Wisley we cover the whole bed with a plastic roof, but they are all small plants which could be plunged out in their pots in the summer and brought back onto a windowsill in winter. They are well worth it for their wonderful display of flowers. Maihuenia poeppigii (see photo, top) is an interesting mat-forming cactus which is permanently planted in a small bed next to our display house. Next to a sunny wall, it stays out all winter unprotected.

Crassula sarcocaulisCrassula sarcocaulis is another beautiful choice for a trough or container. It is not winter hardy except for in very mild areas of the UK, but again is small enough to be moved and gives a lovely show of flowers in late June/July.

At the moment these plants are in flower and really 'doing their thing' so we’re keeping them deadheaded and looking good. You can buy cacti and succulents fairly cheaply at plant centres, and in my opinion they make an unusual and beautiful display. It is great fun to experiment, as long as you are prepared for the occasional loss – especially if left out over winter.

In very dry spells troughs and containers will still need watering but a good watering once a week will suffice; and they are likely to cope very well if they are not watered while you are away on your summer holiday. Ah, the joy of returning to thriving plants!

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