In this series of monthly articles Bob explores the incredible range of plants you can grow in a greenhouse, conservatory or plastic tunnel. Not just the purely decorative but the scented and edible also, and maybe those plants that are just downright interesting. This month Bob nominates the Nycto-Cereus cactus.
Now the Cereus, or Nyctocereus as it’s been renamed, is one of the largest, most highly perfumed, most prolificly blooming tender plants you can ever hope for. Almost hardy, almost completely pest and disease free, yet hardly anyone grows them. True they are slow from seed and not often offered for sale but long lived and easy from slips. Maybe it’s because they have a reputation of flowering but once every forty years or so. Actually they are dead easy to bring into bloom, if not admittedly very quick, when you give them the right treatment. And after flowering, if pollinated, some species can produce edible fruits, one close relative is sometimes sold here in shops as Pithaya. But Nyctocereus is a plant to grow for their floral display. If cultivated like most cacti, dryish and upright in a pot, they can be slow to flower, and especially if watered like most plants at the roots when they are content to simply get bigger. However this is a tree dweller from Mexico, more like a bromeliad in habit, with tough longish stems and flattish leathery leaves. Rather oddly though this is a cactus few of the species have significant spines and in some ways they resemble a form of gigantic mistletoe. So unless you have a convenient tree crotch what this wants is to dangle from a hanging pot or basket -and then flowers will sprout, almost uniquely, from the lowermost tips. And like bromeliads and gardenias these prefer brightish but dappled shade to parching hot sunlight. Also although they will happily grow only too well if fed and watered at the roots it is frequent misting that they really want to encourage blooming! I add a little seaweed and sometimes a drop of fish emulsion occasionally and then find their root-balls can be tiny and neglected yet the plants can still throw plenty of blooms. Now when these swell to long buds the size of zucchini look at them every evening about seven or eight o clock and you should catch them opening. They only bloom the one night closing the following morning, but what blooms. The scent is vanilla and sweet and very very strong whilst the huge bloom itself composed of a multitude of petals is strangely beautiful. And older larger plants can carry over a dozen the same night. What a spectacle, truly a serious cereus.