Your gardening questions answered: How can I boost my Christmas cactus?

My flowering cactus was magnificent for Christmas, but now I have to wait for it to flower again. Is it possible to slip it? Or make it bloom again?

KR, Co Clare

Exotically colourful in flower and exceptionally long-lived (plants more than a century old have been recorded), the Christmas cactus is a very popular houseplant that typically comes into bloom in mid-winter, hence its common name.

Two similar species – Schlumbergera truncata and Schlumbergera × buckleyi – are widely grown, with many different cultivars available that produce flowers in fruity shades of flamingo pink, shocking red and purple as well as white. Unfortunately the Christmas cactus flowers just once a year, but that colourful display does continue over a period of several weeks, while even when out of flower it remains a handsome indoor plant.

In the wild these species can be found growing in the dappled shade of humid tropical rainforests, which gives you a very good clue as to the kind of growing conditions they need. To ensure a really good display next winter, your plant needs a period of enforced rest from January-March to recover its energies, and then another in autumn (mid-September-November), in preparation for its next showy display of those winter blooms. During both of these periods of rest, Christmas cacti need minimal watering, as well as slightly cooler temperatures (12-15 degrees) than they do when in active growth or bloom (18-20 degrees).

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Many people like to put their plants outdoors in summer in a sheltered spot out of direct sunshine, which helps to “ripen” any new growth in preparation for the formation of flower buds later in the year. Just make sure to choose