With the possibility of more heatwaves on the horizon, houseplants, particularly green leafy ones, will need protecting from hot sun, especially if it is through glass. There is one group of plants however for whom hot, dry weather is very welcome, and that is cacti.
Although forest cacti such as Schlumbergera and Rhipsalis, whose natural habitat are tropical rainforests where they grow in semi-shade, do need some shelter from direct sunshine, desert cacti on the other hand can tolerate heat and direct exposure, being used to temperatures of anything up to 32°C in the daytime. They do appreciate cooler nights, the change in temperature being essential to their well-being. Overall, these are ideal plants to promote when temperatures are high.
Wherever cacti are on show, inside or out, do ensure they are shaded from the sun at the hottest part of the day to avoid them being scorched (this is usually between 3pm-6pm). For an indoor display, maximise their appeal by grouping different types together using natural materials such as wood and cork to accentuate their differing shapes and colours.
Create a cactus garden for an imaginative gift. Plant your cacti in a container that will insulate it against sudden fluctuations in temperature using either ceramic, wood or terracotta. A top dressing of pebbles or small stones will not only look attractive, but it will also help the compost to retain moisture. When planting up, use specialist cactus compost if possible, or mix a handful of sand or grit into ordinary compost for optimum drainage.
Children are fascinated by cacti. Planting one into a glass container will allow them to watch the root system develop as well as the plant above.
Despite their desert status, it’s still important to keep your cacti hydrated. Water sparingly either first thing in the morning or last thing at night, when temperatures have cooled down.
They enjoy fresh air, so outside under an awning is the perfect spot for them.
Most cacti will flower only when they reach maturity, keeping them slightly pot bound will encourage this.
Patches of pale white on the stems and spines? This is caused by heat exposure which unfortunately is irreversible although It may be possible to cut away the affected area.
It goes without saying that cacti need careful handing. A pair of gardening gloves kept under the counter is a good idea when dealing with the spinier varieties. Or you can wrap a collar of paper around the cactus to protect your hands when handling or repotting.
Su Whale is a florist and freelance writer with over twenty-five years' experience in the floristry industry. She is the author and publisher of three best-selling books: Cut Flowers, 4th edition (2020) Cut Foliage, 2nd Edition, (2021) and Houseplants (2019), all bookshelf essentials for the professional florist.