Exotic vines bringing vibrant colour to your home, tropical Mandevilla are climbing evergreen perennials which can, when cared for correctly, be grown as houseplants in the right spot.
How to Grow Mandevilla
Flowering time: May to October
Location: A hot and humid spot in a conservatory or other location with bright but indirect light.
Soil: A free draining, peat free, soil based potting mix.
Water: Water moderately but mist daily for humidity.
Care: Rather challenging to care for as houseplants but highly rewarding when given the right conditions.
Mandevilla, also known as Rocktrumpet, are evergreen, perennial vines which come from the tropics of Central and South America. As tropical plants, they cannot thrive outside in cooler temperate areas. However, they can be grown as houseplants in the UK by those who are able to provide the right conditions and put in the requisite care.
This genus is in the Apocynaceae plant family. It was named after the British gardener and diplomat Henry Mandeville who lived between 1773 and 1861.
Why grow Mandevilla?
The reason Mandevilla may be the right option is that when provided with the right conditions, they can be large and dramatic conservatory plants, with vigorous vines metres long – bearing large, beautiful and numerous trumpet-shaped flowers.
According to Thomas O’Rourke from Horticulture Magazine: “Flowers are sometimes strongly scented and will bloom some time between May and October – often for a period of several months. The flowers can be in a range of different colours – usually pink, red, yellow or white.”
Is Mandevilla right for you?
Though Mandevilla are certainly plants which could make a grand statement, it is important to note that they will not be suited to every home.
These are large, woody vines, which will require space, and require rather specific conditions to grow well. Be sure to check the details below to make sure that you can provide the right conditions.
Another thing to bear in mind is that Mandevilla is toxic to people and pets, so it is important to bear this in mind when deciding where to place one.
Which Mandevilla should you consider?
There are three cultivars of Mandevilla particularly prized by British growers, all of which have received a Royal Horticultural Society Award of Garden Merit. (Though of course they are grown indoors and not in the garden at all.)
The first of these is Mandevilla x amoena ‘Alice du Pont’, also known as Mandevilla x amabilis. This climber reaches an eventual height up up to 7m, and bears large pink flowers in late summer.
The next is Mandevilla laxa, or Chilean jasmine. This is a somewhat smaller vine, though it can still reach around 3 to 5m high. This option is highly prized for its extremely fragrant white- or cream-coloured flowers.
Another top option is Mandevilla boliviensis. This vine grows up to 3 or 4m high and has white flowers with yellow centres.
Where to place Mandevilla
A conservatory is the ideal place to grow Mandevilla, but theoretically, it would be possible to grow this plant in any room of sufficient size where this plant’s environmental needs can be met.
Wherever you decide to grow it, remember that Mandevilla typically needs temperatures of at least 10-15°C. Most Mandevilla will lose their leaves below this temperature, (though M. laxa. mentioned above, can cope with short periods when the temperatures dip to around 5°C.).
All Mandevilla prefer as much heat as possible. In spring., temperatures are particularly important for flowers to form. Ideally, the plants need daytime temperatures over 21°C., and temperatures during the night of 18°C.
Mandevilla need a reasonably bright location indoors, but should be positioned out of direct sunlight. The plants can scorch if placed in hot, direct sun.
Make sure you choose a position which is sheltered from extreme temperature fluctuations and not too dry. High humidity is essential. Avoid is spot with draughts or one which is too close to radiators or stoves.
The essentials of Mandevilla care
Mandevilla can be grown from seed, though a heated propagator will be required. Seeds are sown in spring and should germinate at temperatures between 18 and 23°C.
If you purchase a Mandevilla plant rather than growing from seed, repot your Mandevilla into a large container. Remember that you will also need to provide a support for your plant, since these are climbers. A wood trellis, obelisk or other sturdy structure will be required.
The pot should be filled with a free-draining soil based, peat free potting compost such as John Innes no. 2 or a home-made equivalent.
Water moderately, taking care not to overwater, yet being consistent in water supplied over time during the spring and summer. Make sure that the water can always drain away freely. In winter, watering needs will be significantly lower and you should reduce watering accordingly until spring.
Humidity should also be maintained with daily misting over the summer months.
For best results, Mandevilla should be fed with a balanced, organic liquid plant feed every four weeks or so over the summer months.
Mandevilla flower on new wood, so it is important to prune correctly to make sure that you do not miss out on the beautiful blooms. Largely, pruning is undertaken to restrict the size of these vigorous vines.
Pruning after planting involves choosing a few key stems to serve as a framework, cutting out the rest. Or, where there is only a single main stem, reducing its length by around a third in order to encourage a bushier growth habit from the base.
Once these plants are established, they can be given an annual trim in February or March to keep them restricted to the space available. Weak or damaged stems should also be removed, and side shoots can be trimmed to within 3-4 buds of the framework to encourage new flowering wood to form.
It is best to repot Mandevilla in late winter or early spring each year, choosing a larger container as required but at the least replenishing the growing medium to ensure ongoing fertility.
Like other houseplants, many of the problems which can arise with this plant are due to a failure to provide the right conditions, or improper care. They can also fall prey to common houseplant pests, like mealybugs, for example.
Mandevilla certainly are not the easiest houseplants to grow. But if you make sure that their needs are met, they can be real statement pieces inside your home.