HARDY CACTI AND SUCCULENTS FOR GROWING OUTSIDE
With careful selection and skilful arrangement, attractive displays of cacti and other succulents can be grown outdoors – even in relatively cool conditions. However, to get the best out of your more exotic species, plant them into in porous troughs or pots, or even purpose built raised beds – in fact anywhere provided the plants are suitably raised above ground level to allow water to drain away freely.
Few succulents can tolerate excess moisture and even the truly hardy species require good drainage to perform their best. Among the hardiest to consider are the many species and cultivars of Sedums, Sempervivums (houseleeks), along with members of both the Crassula and Umbilicus family.
However, don't overlook the striking purple leaved Aeonium arboreum ‘Schwarzkopf’, and – if you can source it – the hardy Maihuenia poeppigii.
With excellent drainage and a good baking in the summer, a number of desert cacti - particularly some Lampranthus and Opuntia species – will withstand surprisingly low temperatures, although not a combination of cold and wet! Perhaps the best of these is the hardy Opuntia humifusa
If you live in milder areas which experience only a few frosts this range of exotic plants can be extended to include the spectacular rosettes of Agave americana cultivars. With a little winter protection you can also consider Agave filifera, Beschorneria yuccoides.
Half hardy species will need a freely draining site with the shelter of a warm, sunny wall for additional protection. Where temperatures are unlikely to fall much below 7-10 degrees Celsius, such as the Mediterranean or southern and south-western USA, there are few restrictions when choosing succulents for outdoors.
Although neither a cactus or succulent, the hardy bromeliad is more than able to hold its own amongst its desert dwelling brothers. The best two varieties for availability and that will cope with the cold are Puya chilensis and Puya berteroniana.
AGAVE PARRASANA - The Cabbage Head Agave