Cultivation

• All pelargoniums need to be kept in a cool greenhouse over winter. The two species found in the Middle East, P. endlicherianum and P. quercetorum, are reputedly hardy and I know of gardeners in sheltered areas who leave P. sidoides outside year round, but if you want to be sure that your pelargoniums will survive the winter they need to be in a greenhouse, conservatory or coldframe. I grow mine in a loam-based compost that is about one third each of loam, composted bark and horticultural grit. Whatever compost you use it must be well drained: waterlogging is the quickest way to kill off a pelargonium. I use clay pots not only because they are more attractive but also because any excess moisture can evaporate through the clay. Like all plants growing in pots, pelargoniums will need to be fed. Species plants need far less fertiliser than hybrids and I give mine a liquid tomato feed once a month between May and September. • Most pelargoniums thrive in dry, sunny situations but P. tomentosum grows best in dappled shade. Wherever they are grown, pelargoniums benefit from good air circulation, so don’t overcrowd them. • Unless you want to collect seed, cutting back the dead flowers will, in most species, prolong flowering. On plants such as P. sidoides, P. reniforme, P. echinatum and other species with a long flower stem, cut the whole stem off down to the base. With densely floriferous plants, such as P. ionidiflorum, P. australe and P. trifidum, I find it more effective to shear off all the flower stems once the majority have flowered. • At the end of the growing season, before the plants are put into the greenhouse, I cut out any damaged stems and then cut back the whole plant by about two thirds. This can seem drastic but it will ensure that the plant is easier to store and that the increased air flow around it will minimise disease.