It’s a time of year when plant shops seem to be flooded with many of my favourite old-school Victorian houseplants, which these days are thought of – paradoxically, thanks to the widespread adoption of central heating – as incredibly tricky to grow. As so many of these cool-climate species look incredibly exotic, we tend to assume that their decline soon after we get them home is down to our own failure to spoil them with the steamy jungle conditions we are convinced they must require.
I think it’s reassuring to know that the reality is usually the exact opposite. With the current energy crisis causing many of us to consider reducing how many rooms we heat, and the temperature across our homes generally being lowered to a level that’s decidedly chillier, some of these species could really start to come into their own.
I first saw Cymbidium orchids at one of the huge displays of seasonal plants that filled plant nurseries in Singapore during Chinese New Year in the late 1990s. Every year, these stores would literally quadruple in size, with all sorts of unusual, imported species, from 10ft cherry trees in flower, to picture-perfect rice plants sporting full ears of grain and decorated with red silk ribbons, spilling out on to pavements, grass verges and even adjoining car parks.
Back then, the sheer size of these orchids’ blooms and their incredible “corsage” forms just blew my mind. Little did I know that they would prove to be totally impossible for me to keep alive in the heat of the lowland tropics. Three decades on, wandering around central London in the depths of winter, I frequently spot the same genus all over the place in the yards of basement flats, in pots on the concrete patios of council blocks and sitting on forgotten window ledges, where they seem to be thriving outdoors in cold, damp and distinctly un-jungly conditions.
It’s a similar case with almost all citrus plants. Given the combination of warm temperatures and low light levels in winter, many will react by almost instantly shedding their leaves, which can be really tricky to recover from in the spring, leading to a rapid decline.
While these light-loving species will handle a wide range of temperatures, the combination of warm temperatures driving up their metabolic rate coupled with the lack of light (meaning they don’t have the solar energy to fuel this desire for growth) is kind of like hitting the brakes and the accelerator at the same time on their biology.
This is also exactly the case for a wide range of cool-climate houseplants from gardenias and forest cacti, to maidenhair ferns and cyclamen. In fact, cooler winter conditions can be of benefit to houseplants in general, most of which were originally popularised long before central heating became the norm. When you remove central heating from the equation, you remove the damaging effect it has on plant metabolics, and also the raised humidity that comes with it.
Follow James on Twitter @Botanygeek
