How to winter mandevilla?

How to Winterize Your Mandevilla Plant

Many home gardeners wonder about what to do with their mandevilla plants during the winter. How to winterize your mandevillas and what is the best way to prepare them for cold months? Those are just some of the questions home gardeners want to know.

Mandevilla vine is a popular plant many people grow in their homes and gardens. It’s a beautiful spring blooming crop. While it’s sometimes grown indoors, it’s most commonly grown outside, using a trellis. Many mandevilla vines can be seen on porches, patios and decks.

Since most people keep them outdoors, it’s important to know how to properly winterize these plants and make them healthy, strong and ready for the new spring.

Mandevilla Vine in Winter

Mandevilla vine thrives during spring and summer. As the nights begin to cool off and the cold weather approaches, this plant will naturally slow down. It’s a perfect time to prepare them for the winter and the cold weather.

As the nights begin to cool off, it’s best to give your mandevilla plants some food. This will harden them up for the long winter and it will prepare them adequately for the cold months. It’s best to use a liquid fertilizer with a high middle number. For example, use 10-56-14 fertilizer, or the one with a similar ratio.

Make sure to use fertilizer lightly because otherwise you might burn the plants (the well-known “fertilizer burn”). Remember, the point of this feeding is not to promote growth but to simply toughen your plants up and prepare them for winter.

Preparing Your Mandevilla

After you apply the fertilizer, let the plants stay outside as long as possible. A healthy mandevilla plant can be able to handle temperatures in the hight 40s F (only for brief periods, though).

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You should wait as long as the weather permits, but ideally about 3 weeks. After this, prune your mandevilla. Prune the whole plant back. It means not just tipping the plant but cutting it down. Cut it down to about 12 inches above the soil surface.

It’s also a good idea to treat the plant for any potential pest problems before you take it inside for the winter. It’s vital that you don’t bring any pests to your house so make sure to inspect the plant carefully!

The next step for winterizing is to slow down on the water. Let the plant dry a bit and make it use to less watering. This will slow down the plant further and make it even tougher for the winter. Don’t worry about the plant’s well-being: you have given it some fertilizer so it’s strong enough. At the same time, pruning has removed a lot of growth, which means that the requirements for water will drop.

After all these steps, you will be ready to bring your plant inside.

Indoors Maintenance

When you take your mandevilla inside, it’s important to give it as much light as possible. You should make it stay strong but you don’t want to promote growth during winter.

In any case, don’t be surprised by some new growth, since it will likely happen. Your main concern, however, is to keep the plant strong and healthy until spring. Some people choose to place it in a plastic bag and keep in a heated garage. This is just one of the ways you can preserve you mandevilla during winter. Whatever you do, it’s important to keep your plant on the dry side thoughout the winter.

When the spring comes you should be ready to move your mandevilla outside. Don’t be surprised if the growth produces during the winter to be burned off; that’s normal. You can move your mandevilla outside in the spring and it should continue to thrive. This is the best and simplest method for winterizing your mandevilla vine.

You love the display of flowers your ‘rock trumpet’ aka Mandevilla plant produces in the spring and summer. But, what is the deal on caring for Mandevilla in winter? How do you winterize these tropical plants to enjoy the flowers again next spring?

How To Get Your Mandevilla Vine Ready For Winter

As the weather becomes cooler, your Mandevilla’s flower production will slow down.

This is the right time to provide that last meal of fertilizer.

Following this, allow your plant to stay outdoors as long as possible.

It should be able to tolerate overnight temperatures in the high 40s.

  • Weather permitting, toward the end of September, prune your plant back for the winter.
  • You’ll want to cut it back to make it easy to bring in and easy to live with over the winter months.
  • This can be a dramatic pruning, but don’t feel alarmed. Mandevilla is very tolerant of aggressive pruning.
  • You can prune to within a few inches of the soil and still have incredible growth when spring arrives.
  • As you prepare your plant to come winter indoors, examine it carefully for pests or signs of disease and take appropriate steps to address any problems.
  • Your plant will not grow much during the winter months, if you want to enjoy it as a houseplant, don’t overdo the pruning.
  • Trim it back to the size you want, and it will probably stay that way throughout the winter months.
  • You may get a little flurry of leaves or stems when initially bringing the plant indoors. Pinch back the tips as needed.

Be advised that when pruning or pinching your plant back, you will encounter milky sap (like a Poinsettia).

This sap can irritate your skin, and it is toxic to ingest.

It’s a good idea to wear gloves while pruning and wash your hands afterward.

How To Trim a Mandevilla: Garden Savvy

Overwinter Care Of The Mandevilla Vine

When keeping your plant indoors as a houseplant, provide it with bright, indirect sunlight near an east or west-facing sunny window.

Position your plant away from the door, so cold drafts will not harm it.

Kept as a houseplant, your Mandevilla vine or Dipladenia will be comfortable at normal home temperatures in the 60s and 70s. If you keep your home warmer, the plant could dry out.

In this case, maintain the plant in a cooler area of the house and/or use a humidifier to prevent excessively dry air.

Humidifier use is beneficial to people, pets, and houseplants during dry, cold winter months.

During the wintertime, the plant will grow very slowly. Remember you are just trying to maintain it.

Don’t encourage the Mandevilla to grow by feeding it. Just keep it protected and water it lightly when the soil feels dry.

Can A Mandevilla Plant Live Indoors?

The Mandevilla vine can live and grow indoors. I have read of Mandevilla being one of the better “indoor vines” and it could do well in a sunroom with lots of light or a very bright windowsill. However, the plant may vine as a house plant but I would not expect lots of flowers.

How To Transplant Mandevillas for Winter: Gardening Tips

Dormant Overwintering

If you don’t want to bring your Mandevilla indoors during the winter, simply protect it enough to allow it to go dormant.

To do this, allow the plant to stay outdoors until it is quite cool outside, prune it back to about a foot high and move it into your basement or garage.

Take care that it stays above freezing (50° degrees Fahrenheit is best) throughout the winter, or you will lose your plant.

Some gardeners like to put the plants inside a plastic bag for the winter. Others leave them uncovered.

Either way, your plant should not be receiving sunlight. You want it to maintain a complete, resting state.

Just check occasionally to see if the soil is dry. If so, provide a small amount of water.

When it’s almost spring, bring your plants indoors and help them rejuvenate for the growing season.

Getting Mandevilla Ready For Spring

Whether you overwinter plants indoors or in an outbuilding or basement, in February, examine them for signs of illness or distress.

Provide another good pruning to remove any crowded, dead or diseased limbs.

Repot as needed and begin watering and fertilizing for growth. The plants should perk right up and begin growing again.

In late April or early May (earlier in the south), allow the plants a little time outdoors on warm, still, sunny days.

Be sure to bring them in at night and when the temperature dips.

As the weather becomes more and more reliably warm, allow the plants more time to harden and acclimate to the outdoor life.

If your Mandevilla vine has put on some new growth during the winter, this will probably die back.

Don’t be alarmed! This is normal. The plant will soon be putting out lots of healthy new growth.

When all danger of frost passes and the weather is generally comfortable, place your acclimated plants in their spring and summertime positions in the landscape.

How to Winterize a Mandevilla Vine

As days shorten and nights begin to cool, your rapidly growing mandevilla will begin to slow down in preparation for a restful winter. The beautiful, exotic mandevilla was never meant to live indoors, and it knows it. But it won’t survive temperatures below 45 degrees Fahrenheit, so it will require a little special management for successful wintering indoors. This is much easier to do than you might think, and you won’t need a greenhouse or any fancy equipment. A little common sense will ensure that your beautiful tropical vine makes it through the winter to perform beautifully next spring.

Dig up your mandevilla and pot it three to four weeks before the first predicted frost for your area, usually in September. Leave it next to its customary spot to begin hardening off for the winter. Give it one last seasonal feeding of water-soluble liquid fertilizer to toughen it up. Water a little only when the soil completely dries out for the rest of the winter.

Bring the mandevilla indoors when overnight temperatures dip to 45 F. This is roughly about the time that most people begin closing their windows and turning on the heat. Place the plant in a cool, sunny location. Don’t be alarmed when it begins to drop its leaves because of lowered humidity, and don’t try to increase the humidity. This is normal, and you can expect the mandevilla to begin to look ratty.

Treat the plant for insects with an application of insecticidal soap because you’re bringing it inside. Water it only when the soil dries out completely.

Prune the mandevilla back hard the first of February. Cut stems to 12 inches above the soil line. Begin monthly maintenance feedings of half-strength water-soluble fertilizer.

Saturate the root ball with water one time in early spring when the mandevilla begins to develop new shoots. Thereafter, water only enough to barely moisten the soil surface. Always allow the surface of the soil to dry out before watering again.

Feed a full strength solution of water-soluble fertilizer in May or June, about three weeks before the last predicted frost in your area. Begin regular feedings per the packaging instructions and continue throughout the growing season. Begin pinching off new shoots to encourage bushier growth.

Move the mandevilla vine to a sunny spot outside for an hour each morning for several days in May, once daytime temperatures no longer drop below about 50 F. This will begin the plant’s acclimation to living outside again. Bring it in before the sun gets hot for the first few days. Gradually increase the outside time over the course of a couple of weeks, working up to eight hours of full sun daily.

Replant the mandevilla in its prior outdoor location after all danger of frost has passed.

In the Garden

Potted mandevillas are popular additions to summer gardens. These South American vines feature glossy, dark-green leaves and stunning white, pink or red trumpet-shaped flowers that add color all summer.

Not surprisingly, the nectar-rich blossoms are irresistible to hummingbirds.

Unfortunately, mandevillas are tropical plants and can’t withstand temperatures much below 50 degrees. If you want to keep your mandevilla alive over the winter, bring it inside as a houseplant during the cold season.

Gardening Events

Soos Creek Botanical Garden Fall Plant Sale:

Skagit Valley Giant Pumpkin Festival:

9 a.m. to 5 p.m. Saturday, Sept. 24 (festivities begin at 11 a.m.). Cash prizes for the biggest pumpkins. Besides huge pumpkins, there will be a free talk by Kathleen Bander of Bats Northwest (reservations requested at 360-466-3821), live music, toad races, beer garden and more. Cost: Free admission; a small charge for pony rides and face-painting. Address: Christianson’s Nursery, 15806 Best Road, Mount Vernon.

King County Master Gardeners’ Cool Plants & Hot Topics:

9:30 a.m. to 4:30 p.m. Saturday, Sept. 24. Fall plant sale and speakers. Many specialty nurseries will be featured. Tool-sharpening, information booth and rain-garden clinic. Register to attend the entire day of lectures. Limited same-day tickets might be available for individual talks. Address: Bellevue Botanical Garden, 12001 Main St., Bellevue.

Trim the vines to a reasonable size, and check the plant carefully for bugs. You don’t want to introduce a pest infestation into your houseplant collection, and you definitely don’t want a stowaway slug leaving a slime trail across expensive furniture.

Place the plant in direct sunlight, such as in front of a south or west window, and keep humidity as high as possible. Although unlikely to bloom indoors, mandevillas remain in active growth in winter, so water whenever the soil feels dry, 1 inch deep. Wait to fertilize until March; then feed every two weeks with a soluble houseplant food.

In spring, place the plant outside on nice days, but wait to leave it out for the summer until night temperatures remain in the high 50s.

If you lack sufficient light, another often-recommended method is to allow it to go dormant and store it in an unheated garage. Don’t bother: When I tried this, my mandevilla took so long to break dormancy, it didn’t even start flowering until late summer. If this happens, toss it in the compost bin and buy one that already is in bloom next spring.

It’s time to renovate your lawn

If you’re like the majority of homeowners in our region, you don’t water your lawn in summer, allowing it to go dormant. Now that temperatures are moderating, the grass should be coming back out of dormancy, but don’t be surprised if the turf has thinned out, especially if you held off watering for a number of summers in a row.

Thin turf is more susceptible to moss and weed problems. Moss is opportunistic, and quickly colonizes-thinned out lawns, and the weed seeds such as dandelions and clover germinate much more readily.

To solve the problem, renovate and overseed your lawn, ideally from mid-September to mid-October. Begin by spraying dandelions and other broad-leaved weeds with a liberal dose of straight white vinegar. Pick a sunny day, because vinegar works only in warm, dry weather. The vinegar will kill any grass it hits, but it doesn’t matter as long as you overseed as part of the renovation process.

If moss is a problem, rent a dethatching machine to remove the moss; then apply a moss-control product, heeding package instructions. The next step is to rent an aerifying machine and use it to punch gazillions of holes in the turf.

Look for a 50-50 mix by weight of fine fescue and perennial rye grass, or as close to a 50-50 mix as you can find. Overseed the lawn, making sure to rake as much seed as possible into the holes.

Apply an organic lawn fertilizer, and keep the soil surface moist. Before you know it, your lawn will look spectacular. If you do this hard work every few years (or hire a company) your lawn will not only look more attractive, it will be better able to resist future moss and weed problems, even if you continue to allow your grass to go dormant.

Dipladenia can be wintered successfully

A: Dipladenia, and its close relative mandevilla, can be wintered successfully indoors and then returned outdoors next spring. We enjoy wintering several each year, and they aren’t difficult if given full, direct, bright sunshine in front of a large, sunny window. Before bringing indoors, wash the plants with the garden hose to reduce tag-along insects. Plants can be pruned if they’ve grown large and repotted now or next spring.

If given enough sunlight, dipladenia will thrive and sometimes bloom indoors. Don’t be alarmed if a few leaves turn yellow and drop. Water as you would other houseplants, letting them dry between thorough watering. If leaves are yellowing and dropping, decrease watering frequency. Fertilize with water-soluble fertilizer once a month.

To prevent insect problems, apply granular systemic houseplant insecticide to the soil. In March, prune the plants back, preferably quite severely to encourage good branching, or at least enough to remove weak winter growth. Repot if necessary into fresh soil, and begin fertilizing every two weeks. Move back outdoors in May after frost danger passes.

Q: I have four trough-like planters on a concrete patio. Each is four feet long and one foot wide and tall. Will any perennials or bulbs such as tulips, crocus and daffodils survive the winter in the planters? – Gary Euren, Moorhead.

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A: Unfortunately, planters that are above natural ground level are subjected to temperatures too severe for bulbs and perennials to survive. Below natural ground level, soil is more moderately frozen, but planters above ground easily take on the air temperature.

For example, a check of weather records shows that last January in Fargo on a day with air temperature nearly 20 degrees below zero, underground soil temperature was 20 degrees above zero, nearly a 40-degree difference.

If you’d like to try, move the planters to a protected spot along the house foundation and cover with at least several feet of leaves or straw for insulation, and then uncover next spring and move to their desired location. Annual flowers are still the best solution for above-ground planters.

Q: My lawn is top heavy with thick tops, but very shallow roots. My mower is set at three and a half inches, and I was watering daily for 10 to 20 minutes per zone. I think I’m mowing too high and watering too often even though it’s been a dry summer. – Jeff Greenheck, Fargo.

A: Your suspicions are probably accurate about watering too often, and the mowing height could be reduced to the preferred three inches. Shallow rooting is usually caused by watering too frequently, which encourages roots to stay near the surface instead of growing downward. The preferred rule of thumb is to apply one inch of water per week in one application, or split between two waterings if soil texture is light. To monitor quantity, locate a straight-sided soup can within the sprinkling zone. Less frequent, but deep watering will keep a lawn green and healthy with a deep, vigorous root system.

If you have a gardening or lawn care question, email Don Kinzler at [email protected] All questions will be answered, and those with broad appeal may be published, so please include your name, city and state for appropriate advice.

Overwintered dipladenia should bloom soon

Dipladenia and its close relative mandevilla usually winter indoors quite successfully if you have a full-sun window and if you monitor closely for insects. Both are prone to attacks indoors by aphids and spider mites. Applying a systemic insecticide to the potting soil in autumn when the plant moves indoors helps greatly.

Q: I have two large peony plants on the south side of my house, one white and the other rose colored. They are quite old plants. The last few years when they start to flower, the buds turn brown and when the flower opens, the edges are all brown. They used to be such a pretty white and rose color. What happened to them and what can I do to get rid of the brown? — Dorothy Tretter, Hope, N.D.

A: There are two possibilities. First, peonies can remain in the same place for many, many years, with no need to dig and divide. But if they no longer flower nicely, as they once did, then dividing in September can improve health. Most old peonies can be divided into at least four sections, sometimes more. When replanting, locate the uppermost “eye,” which are the buds located in the roots, at about 1.5 inches below soil surface. Planting too deeply interferes with flowering.

A second possibility of bud and flower browning is peony blight, caused by fungi. In spring, when plants reach about 12 inches in height, spray or drench the plant with an all-purpose fungicide containing the active ingredient chlorothalonil. Repeat following label directions. Although most perennials winter best with their tops left intact, peonies are an exception. Because their tops can be sources of fungal infection, cut peonies down to several inches above ground level after several fall frosts.

Q: My lawn has become mostly wild violets. I tried the new lawn-safe Roundup and am very disappointed. It works no better than Weed-B-Gon on dandelions and does not kill violets or creeping Charlie. — Lynn Tkachuk, Moorhead.

A: Wild violets, with their heart-shaped leaves and lavender flowers, are a very persistent perennial weed, and multiple sprays over several years is usually necessary for control. Triclopyr is the active ingredient recommended by Purdue University and others as having the greatest effect on violets, so search the product labels.

Spray the product following label directions in May and June, and again in September, which is the most important application of all. In autumn, weeds carry the chemical down into their roots as they’re storing other material for their winter survival.

If you have a gardening or lawn care question, email Don Kinzler at [email protected] All questions will be answered, and those with broad appeal may be published, so please include your name, city and state for appropriate advice.

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