Dipladenia or Mandevilla?

Many of you might remember when the rock star Prince changed his name to a symbol. Since the symbol wasn’t pronounceable, because that would just be another name after all, he became “the artist formerly known as Prince.” I think of this every time I pass the baskets of ‘Red Riding Hood’ Mandevilla in the store. “Oh yes,” I’ve told customers, “that’s the plant formerly known as Dipladenia.”

In the garden center the confusion over Mandevilla plants is as tangled as the larger growing versions of this vine. Since the early 1900’s, when these plants became popular in Europe, the larger growing varieties were called Mandevilla and the shorter, bushier types Dipladenia. Now, however, botanists have reclassified them all into the genus Mandevilla.

People love the tall, vigorously vining form of Mandevilla for covering railings, lamp posts and trellises.

Why the name change? Well, it used to be that plants were named based on how they looked. If a particular group of plants had similar growth characteristics, or looked the same, they were bunched together into a genus and given different species names. But now scientists are able to look at plants on a genetic basis; botanists can tell if plants with a similar look are actually related or not.

In some cases this results in plants that used to be in the same genus being broken up and given new, separate names. This recently happened with the Asters. In other instances plants that had separate labels before are grouped into the same genus because it’s seen that they are genetically very similar. That’s the case with Mandevilla.

In the garden center we want to be as horticulturally correct as possible, but change doesn’t come quickly or easily. Habits can be hard to alter. Some of our growers still label the shorter versions of this plant as Dipladenia and many of our customers or employees still use this as a common name for the plant. This can cause miscommunications and confusion.

The shorter varieties of Mandevilla vine, formerly called Dipladenia, make good spillers in full sun. There are several colors available and they don’t have to be deadheaded as ivy geraniums often do.

The answer might ultimately lie in using the cultivar name to be sure you’re getting what you want. “I’m looking for a ‘Alice Dupont’ Mandevilla,” for example, or “Do you have Sun Parasol White Mandevilla?” Even then there will be confusion as new varieties of this splendid annual are always being introduced. (Plant lust alert: beautiful yellow varieties will be available in 2017.)

Returning back to “the artist formerly known as Prince,” I think it’s amusing that in some parts of the world, Mandevilla plants are commonly called “rocktrumpet.” Whatever you call this annual vine, choose the variety whose size suits the location where you’re growing it. Use shorter, bush versions for hanging baskets and containers, and taller, vining types for trellises, lampposts and arbors. Grow them in sun, fertilize regularly, then stand back and rock on.