Yes, mandevilla come back every year in warm climates where frost never touches the ground. If you live in USDA Zones 10 or 11, your vine will keep growing through winter without any help. Gardeners in colder zones can still bring these plants back each spring with a bit of extra effort on their part.
Your local climate decides how this vine behaves. A mandevilla perennial grows year-round in frost-free areas like South Florida. The vine stays green through every season in those warm regions. North of Zone 9, the roots can't handle frozen soil. Most gardeners there treat it as a tender plant that needs indoor shelter during cold months. The good news is that both approaches give you a vine full of blooms each summer.
One notable exception is M. laxa, with roots that survive down to 5°F (-15°C) per Clemson Extension. This species is the hardiest in the whole group. The top growth will die back in a hard freeze. Yet the roots push out fresh vines the next spring without indoor storage at all. If you can find M. laxa at a local nursery, it's worth planting in Zone 7 or warmer. The white fragrant flowers on this species are smaller than other types, but the cold hardiness more than makes up for it.
I've kept mandevilla alive indoors through winter in a Zone 6 climate for several years. The vine comes back stronger each spring and produces more blooms than it did the year before. My first year I was nervous watching it drop leaves and go bare by mid-December. The stems looked dead and I almost gave up on it. By March, tiny green buds popped up along those same bare stems. Within weeks the whole plant was covered in fresh growth. That taught me these vines are much tougher than most people think.
A neighbor of mine used to buy a new mandevilla annual each May and toss it after the first frost. I convinced her to try overwintering one year using my garage method. Her vine came back with twice as many flowers the second season and the stems were noticeably thicker. She hasn't bought a new plant since. The savings add up fast when you aren't spending $20-$30 on a fresh plant each spring. That money goes much further toward good potting soil and fertilizer.
You have two solid strategies for keeping your plant alive through winter. The first option is bringing it indoors as a houseplant near a south-facing window with at least four hours of direct sun. Keep the soil lightly moist and skip all fertilizer until spring. The second option works if you have a cool garage or basement that stays above 50°F (10°C). Cut the vine back by about one-third. Water it once every two to three weeks and let it rest in the dark. I've had good results with both methods depending on the space I had that year.
Start getting your plant ready for the move once nighttime temps drop below 55°F (12.8°C) in fall. Check the leaves and stems for pests before bringing the pot inside your home. Spray it down with a garden hose to knock off any hitchhikers. Look under each leaf for whiteflies and spider mites since those are the most common stowaways. A quick wipe with soapy water handles most problems before they spread indoors.
Come spring, move the vine back outdoors after your last frost date passes. Don't rush this step or a late cold snap could set the plant back by weeks. Resume regular watering and a 10-20-10 fertilizer at that point to fuel new growth. Give it a few weeks in full sun and you'll see fresh buds forming along the stems. Your mandevilla will reward you with more blooms than it gave you the year before.
Read the full article: Mandevilla Plant Care and Growing Guide
