Garden Gossip

with Ted Smith

I have a confession to make. I am a plant addict. It is virtually impossible for me to drive past a greenhouse without stopping to take a look. Once inside, it is pretty well understood that I will be leaving with something new. Considering that plant appropriate space in my home is finite, this is often a source of great stress for me. Just not enough stress to prevent history from repeating itself at every possible opportunity. Recently I was in Sudbury and fate, as it always seems to, brought me to the door of my favourite nursery. The day’s outcome was never in question and I left said greenhouse with more new plants than it seemed could possibly fit in my truck. One of my purchases was particularly exciting as it came with a healthy dose of nostalgia. 

Having lived, and gardened, in South Texas for many years, I have been fortunate to have been able to grow some pretty exotic plants. On rare occasions, I see these plants show up for sale on local shelves. The plants that I stumbled across on this particular expedition came loaded with Texas nostalgia. For those of you who have never seen a Mandevilla vine in bloom, it may be difficult to understand my excitement. Those of you who have seen these tropical vines in all their glory will understand why I had to be sure and get one of each colour that was being offered for sale. Mandevillas produce huge trumpet flowers of white, pink, yellow and red. I’m pretty sure that I mentioned my plant addiction?

Mandevillas are tropical flowering vines that are native across South America, Central America, Mexico and even into the extreme Southwestern United States. The particular genus that most modern cultivars have descended from was first discovered in Rio De Janeiro in the mid 1800s. Sadly, that particular plant is now considered extinct in its natural setting. Initially, Mandevilla vines that were imported by various plant breeders in Europe failed to live up to the promise they had showed in their natural jungle settings. Interest waned for a while until some Danish horticulturists decided to begin working with Mandevillas in an effort to unlock their potential. Low light and low temperatures were the main hurdles standing in the way of the Danes but they eventually bred Mandevilla vines with traits that allowed them to excel in climates that were a little harsher than they had naturally evolved in. 

There is another plant that often shows up and adds some confusion to the Mandevilla discussion. Dipladenia is a member of the Mandevilla family. While Mandevilla generally refers to the long vining members of the family and Dipladenia is used in reference to the bushier growing varieties, they are both in actuality just different forms of Mandevilla.

As is typical of tropical vines, Mandevillas thrive on warmth, humidity and bright indirect light. Too much direct sun can burn tender Mandevilla leaves so careful location is critical. Also typical of many tropical plants, Mandevilla enjoys fairly rich and damp but well drained soil. A sandy peat potting soil is a perfect fit for these vines. Keeping Mandevillas in large pots makes it easier to meet their requirements but care must then be taken to ensure the plants get regular watering. They will also thrive planted directly into the ground as long as thought is given to soil drainage, wind exposure and sunlight. Be sure that your Mandevilla vines have access to suitable support for climbing. Their climbing is achieved by twining around supports, usually in a counter-clockwise direction. If you’d like to encourage a bushier growth habit, simply pinch out the growing tip of your vine to force it to create more side shoots. Fertilization of Mandevillas is pretty straightforward. Mandevillas like a fairly well balanced plant food that leans towards being richer in phosphorous (i.e. 10-20-10). 

As you would expect of a plant hailing from Brazil, Mandevillas are extremely sensitive to cool temperatures. This results in them generally being utilized as annual flowers by most northern growers who are lucky enough to find them offered for sale. With a little care, your Mandevilla vine can easily transition into the house for the winter months where it will essentially need to go dormant until light and temperature levels return to what it prefers.

If you decide to move Mandevillas indoors, cut them back by one third and check them carefully for scale, aphids, spider mites and mealy bugs. Mandevillas are highly attractive to these pests. Alternately, simply take cuttings in early fall and create small clones which will be much easier to manage.

Armed with this brief introduction, I hope a few of you search out the incredible Mandevilla vine and fall in love as I did. It’s an addiction.