A rewarding impulse purchase
Buying plants is not the same as buying a new dishwasher. I doubt most gardeners would just pick the prettiest appliance. We’d at least want to know how well it would wash the dishes.
But when plants, particularly annuals, are displayed at garden centres, in flower and blooming beautifully, they’re the ones we most often choose.
Wise shoppers do their research first and source the exact plants they need, and I might do that too. Yet it’s hard to resist when something new or unique shows up, and I’m a sucker for an impulse purchase.
It happened again last week when I spotted a dipladenia and I had to have it. It had yellow flowers, which was a change from the more familiar reds and pinks. You might be calling it a mandevilla — the names are often used interchangeably, although dipladenia appears to be gaining ground, though it is, botanically, also a mandevilla.
Mandevilla is a tropical vine, sometimes called rock trumpet or Brazilian jasmine, and there are hundreds of species, many of which originate in southern North America. They’re also found in forests in Brazil. And that’s how Mandevilla got its name.
A fellow called Henry Frederick Conrad Sander came across them in forests near Rio de Janeiro. He sent one back to England where the people who classify plants must have decided that name was far too long, or that Sander wasn’t high enough in social standing, so they named it after Sir Henry John Mandeville, a diplomat to Buenos Aires. Not Rio, but close enough, I guess. A few decades later, after sorting out the many species, the larger ones were called mandevilla, while smaller, bushlike ones with smaller, pointier leaves were given the name dipladenia. Then they all were reclassified in the mandevilla genus, which includes around 200 species and an ever-increasing number of hybrids.
The difference between the two is mandevilla has larger leaves and if you want a plant to grow three metres or more up a trellis or arbour, this is the one. In its home forest, it can reach twice as high as it clambers to the sun.
The trumpet-shaped flowers on both are much the same, though a little smaller on dipladenia. It’s the more compact plant with smaller flowers, and although it does have tendrils, it’s a lazy climber compared to mandevilla. This makes it perfect in planters and that’s why, being so popular, the name has stuck, even though it’s still a mandevilla.
Now we’ve sorted them out, caring for either is the same. They’ll grow well in full sun to partial shade in soil that drains well. They can be grown in the flower bed, but most often they’re found in a planter, as mine is.
To keep a dipladenia shrubby, pinch back any wayward stems to control it. It won’t need a trellis, but it might need a stake or two. The roots of the plant are like tubers and because they can store water, they are more forgiving if someone forgets, but not for long. It’s best if the soil stays moist like a damp sponge. Regular fertilizing with liquid or slow-release granules will keep it performing well.
In fall, before it turns cold, bring your dipladenia indoors for winter. Check for pests first or you’ll be fighting spider mites or other bugs all winter. It might take repeat applications of insecticidal soap to get them under control. When days are short, the plant might look hung over, but don’t give up on it as they can usually be cut back and revived.
New dishwasher arriving next week. I don’t know what colour, but I’m pretty sure it will wash plant pots just fine.