Gardening with Gary

Gardening Advice from an Expert

Mandevilla Vine

Member Ada writes~ How do I take care of a Mandevilla vine thru the winter? Now it is in a pot outside. I live in Missouri.

A. Mandevilla has become a big spring blooming favorite, and is usually grown outside on a deck, patio, sun porch, etc. As the nights begin to cool off, the plants will slow down. So now is the time to give them some food to harden them up for the long winter.

Try to use a liquid fertilizer with a high middle number [P] as 10-50-12, lightly applied. This is not to promote growth but to toughen the plant. Do not go overboard with the fertilizer. Let the plant stay outside as long as possible. It should be able to handle high 40's for brief periods. After about 3 weeks (if you can hold out that long weather permitting) prune the plant back...not just tip cutting the plant, but cutting down to 12" above the soil.

Next, slow up on the water and let the plant stay on the dry side. Remember the plant received some fertilizer and a lot of growth was removed, so requirements for water will drop. When you bring the plant inside, place it in as much light as possible, looking for maintenance, not growth. You will probably get some new growth, but try to maintain it. Keep the plant on the dry side throughout the winter.

When spring comes, move the plant outside. Expect the growth produced during the winter to be burned off. Some people have even placed the plant in a clear plastic bag and overwintered it in their heated garage.

There is a new variety released this past spring. Usually we see the pink and the white varieties. This new one is red and is called “Best Red”. Well-formed bright red flowers, and the plant looks similar in growth to the variety “Alice DuPont”.

Member Bets writes~
My Mandevilla will not bloom. When I bought it, it was blooming and I transplanted it and it has not bloomed since. It is very healthy. Growing great. Thanks for any help you might can give. Great work.

A. I do not know your zone, but trust that you do not receive freezing temps. Check these descriptions to see if you are caring for them properly. Known for showy flowers, they can be treated as annuals outdoors or grown indoors. They can be brought indoors before the first freeze and treated as a houseplant during the winter months. In the spring, Mandevilla can be returned outside after the last freeze.

Mandevilla is great trellised in containers or in hanging baskets. Quantities of fragrant flowers compensate for sparse foliage and for the care Mandevilla require. The flowers are produced in early summer and again in early fall, even when plants are very young. Indoors, Mandevilla need curtain-filtered or bright indirect sunlight. Provide night temperatures of 60 to 65F.

Plant in a mixture of equal parts peat moss, potting mix and builder's sand. In spring and summer, feed every two weeks with a fertilizer high in phosphorus such as 10-20-10. Outdoors, grow Mandevilla in full sun to partial shade. They need rich, well-drained, sandy soil with humus added. Provide a frame, trellis or stake for support. Pinch young plants to induce bushiness.

This neatly growing woody vine is popular in warmer climates for its beautiful pink funnel shaped flowers. The leathery leaves are dark green and about 7" long. Flowers mainly in the summertime, but will also bloom occasionally throughout the year. Given adequate care, Mandevilla is pest-free and fast growing. Provide plenty of sun for best flowering, but they will take part shade. Vines need adequate moisture, but can survive short droughts and likes well-drained soil. Propagate by cuttings in the spring.

Hardiness: USDA Zones 9-11.

Recommendations:

‘Red Riding Hood' has deep red flowers.

‘Summer Snow' has sparkling white 3- to 4- inch flowers against dark glossy foliage.

‘Yellow' has wide, bright yellow flowers. They are lower growing and shrubbier than the species and superb in hanging baskets.

Prepared with articles by Marjan Kluepfel and Bob Polomski, Extension Consumer Horticulturist, Clemson University and http://www.streetside.com/plants

Susan writes~
I have a Mandevilla plant I purchased last fall and kept it in its pot over the winter on my deck (told it was an outside plant). I live in Ct. and it is now brown with dried leaves. Do you think it will come back. Any hints on what I might do to help save it? Or do you think its gone?

A. Mandevilla has become a very popular spring blooming plant and is usually grown outside on a deck, patio or porch. As the nights begin to cool, the plant growth will slow. Give food to harden for the long winter using a fertilizer with a high middle number as 10-56-14. This is not to promote growth but to toughen. It can handle high 40F for brief periods. Your plant most likely froze. After about 3 weeks, prune plant back to about 12" above the soil line. Begin slowing up on the water letting the plant stay on the dry side. Bring the plant inside into as much light as possible for maintenance not growth. Keep on the dry side throughout the winter. When spring comes, move outside. Expect the growth that was produced during the winter to be burned off. Some growers place the plant in a clear plastic bag [with a couple air holes] and overwinter it in its own heat. Most common are the pink and white varieties but a new one is red and carries the name “Best Red”. With well-formed bright red flowers, the plant looks similar in growth to the variety “Alice DuPont”.