How to Winterize Oleander (Overwintering Guide)

Nerium oleander is a flowering shrub that many gardeners would love to keep over the winter into the next season (by overwintering it, of course)!

Who’d wanna give up those pretty blooms towering on the dark green stalks of foliage!

Not I. That’s for sure. I’ve worked too hard for my blooms to be killed by the winter. So that’s why you winterize it! Then you can see them all over again next season.

When grown under optimal conditions, this shrub produces a variety of pink, white, and orange flowers. It’s known for its numerous blossoms throughout the summer.

It’s also extremely virulent because it can sustain sweltering temperatures, drought, deer, and even salt.

You may think that oleander is an all-around hardy plant. Until you bring up the subject of winter.

Nope. Oleander has poor tolerance to the cold. So this is why people freak out over winterizing it.

It will grow as a perennial, but only if it’s kept warm enough. For people in USDA hardiness zones 8-11, you should have minimal issues getting it to overwinter.

But if you’re in a cooler zone, there are some things you need to do to keep it safe throughout the cold.

Some people have successfully winterized oleander even in zones 4, 5, 6, or 7, which are unrelenting in the cold.

How is this even possible in temperatures that dip below 5F?

There are some tricks you can do to help it thrive throughout the winter. But you’ll need to take action.

Oleander doesn’t fare well on its own if you’re in no man’s land. It does need winter protection for these zones.

Now let’s go over everything you need to know to overwinter oleander.

Poison warning

Oleander may be pleasant to look at, but it’s extremely dangerous to touch or ingest. This is why you should always wear protective equipment when handling this plant.

If ingested, it can be fatal to people or pets. Thus, if you’re keeping oleander indoors for the winter, you NEED to keep it out of reach from pets or people.

Oleander is poisonous, so you may not want to bring it indoors to overwinter it. Take steps to protect yourself and others.

Always wear gloves, sleeves, and other protective gear when touching it. All parts of the plant should be assumed as poisonous as they can cause skin irritation or other reactions from the saponins.

What hardiness zones need to winterize oleander?

Oleander will tolerate the cold in zones 8 or higher. Most oleanders grown within the warmer zones can be left on their own without an issue.

Feel free to cut them back or shape them for the winter. This will help prevent pests from eating the foliage as it wilts back.

Zones 3-7 will have difficulty keeping them going through the winter because temps can dip below 5F. If you don’t winterize it, it can be severely damaged by the elements.

This is when you need to do some work to keep them safe!

So in summary:

• Zones 8 or higher just need regular pruning for the winter. Watch out for temperature dips. If these are expected, you may have to put some mulch to help insulate it. You Can grow it as a perennial in the garden without worry.
• Zones 7 or lower need to winterize their N. oleander.

What temperature can oleander tolerate?

10F is the key temperature to keep in mind. Anything colder than this will harm your plant.

How to winterize oleander

This section covers a variety of techniques you can practice to help your oleander sustain over the wintertime.

Depending on your USDA hardiness zone, you may be able to sneak by with minimal interference. If it gets too cold, then yeah, you’ll need to use some more extreme techniques.

Read through the following list and see which applies to your local climate.

Know the climate patterns

While no one can predict the weather, you can often get a feel for the upcoming dips in temperature.

You need to know when the temp is getting close to 10F so you can be prepared. If you’re too late to act, it can kill your plant.

Keep a gardening journal so you know when to expect the cold snap to take place. Keep tabs on the weather so you can anticipate when the temps may be getting to the danger zone.

While established oleander can handle the cold and even snow, you need to move it inside before this happens. No two seasons are alike, but the dates should be approximate.

Plant your oleander using pots!

This is the most critical piece of advice you can get in regards to success winterizing oleander. Plant them in pots.

This makes it possible to move them to shelter in the event of a cold snap. If you planted it in the soil, you’re not going to be able to uproot it to move it around, especially once it becomes established.

Plan if you’re in a zone expecting temperatures to dip in winter to levels that oleander can’t tolerate.

While it’s possible to dig them up, they don’t take well to it. And it’s not worth the time/effort you need to put into it when you can just plant it in a pot in the first place.

So why not just do it right from the start?

Put the container on a rolling cart. This will make it easier to move it without hurting yourself. Fully sized oleander is extremely heavy and you won’t be able to remove it from the pot without professional help.

Heavy pots will be a common denominator.

So if you have a rolling cart to put the pot on, it’ll help when you need to move it later for the changing seasons. It’ll encourage you to do so too. Who wants to lift waterlogged oleander?

Choose smaller oleander varieties (dwarves)

Picking a smaller variety of oleander will help make it easier on you during the move. Some species only grow up to 3 feet tall.

Consider growing these species into pots so you can bring them inside the house without much hassle.

If you’re in a cooler zone, you’ll have to compensate for the winter by growing a smaller variety.

Use a lightweight planter

Picking the right size, material, and type of container makes a huge impact later on. Everything from how well your oleander fares to how much water it retains completely depends on the planter you choose.

For starters, make sure it has proper drainage.

It should have multiple drainage holes so it doesn’t get clogged. Get the largest container necessary for your plant type, but nothing more so it doesn’t need to be bulkier than it is.

Choose a lightweight material so that it’s lighter to move. Plastic is cheap, light, and colorful, but has near zero insulation.

On the other hand, materials like terra cotta are heavy, but they hold their temperature. This is important because they heat up during the day and carry it into the night which can help insulate your oleander from sudden temperature swings.

Mulch before the storm

If your plant is less than 12-14” in height, try adding some mulch around the base of the plant. This will insulate the roots from winter damage.

It also helps keep the soil wet and retain moisture. Mulching is winterizing 101. It’s the most straightforward way to do it.

When you put the mulch, apply it around the base of the stem and over the roots. If you miss a spot, it can cut off circulation to a portion of your plant. For younger plants, this is imperative.

Established oleander, they don’t need as much care as they’ve developed hardiness to the cold. Ensure that all the roots are covered with thick layers of mulch. Avoid patting down. The primary stem shouldn’t be touching the mulch layer as this may introduce fungal problems.

In a potted plant, this is easy to do. Just cover the entire soil surface with mulch. For garden sown plants, it can be hard to know where the roots are going.

But then again, you shouldn’t be planting your oleander directly into the soil if you’re somewhere that gets too cold. It needs portability.

Use plant wraps

Cover up those plants with some burlap wraps, felt, wool, paper, or plastic. With wraps, they can keep your plants warm for brief temperature drops.

These are NOT a solution to use all winter. They’re just easy solutions for when the temperatures hover around that 40-50F zone.

Wrap as much of the primary stems, then remove when temperatures pick up again. Keeping them on may wilt the plant as they can block photosynthesis. These are a cheap way to winterize oleander, but require it to be pruned first.

Try cold frames

Cold frames can be used for smaller seedling oleanders. You can buy or build a DIY cold frame. They’re excellent for cooler temperatures where you can’t move the oleander indoors.

While they do require some work to set up, they’re a good solution to keep around the plant so you can block out the cold on cue.

This video shows you how to use a cold frame for oleander so you get an idea of how they work:

If you’re handy, you can build one for a cheap custom. They’re actually pretty neat.

Install plant covers

Plant covers can be used for smaller oleander seedlings. There are also larger sizes, but it may not be practical to cover such a large bush because of the unwieldiness.

But for smaller shrubs, you can cover them with plant covers to safeguard them from bugs, temperature swings, and sun.

These are not meant to be a permanent solution. They’re only to be used for smaller dips in temperature. The material will affect how well the cover insulates the oleander itself.

Plant in a greenhouse

Planting inside a temperature-controlled greenhouse can be suitable for oleander throughout the season.

This will ensure that you’ll never have to worry about it being too cold. If you don’t want to keep it there throughout the season, you can move it outside from spring to fall.

Remember that it’s important to keep the temperatures above 40F, but it still needs a cold period so it knows it’s wintertime. If you don’t, it’ll never know when it’s winter so it can mess up the production.

Prune your oleander before the winter

Keep your oleander well pruned so the ends you cut off will be ready for winter. The ideal time to do this is in the late summertime.

Start by cutting back the tips to shape and tidy it up.

Remove spent flowers, cut ugly branches, and trim them down to a compact size. This will make it easier to move around for the cold season. Prune after it blooms in the autumn so you don’t have to do it later.

By pruning after flowers, you get to enjoy the blooms without sacrificing them for the winter. Cut the flowering shoots to half size. Tip prune the other shoots.

Oleander doesn’t need to be pruned every year, but doing so helps encourage flowering and makes it easier to bring inside.

How to overwinter oleander

When it’s too cold out, you can bring your oleander inside your house for temporary shelter. In cooler zones, this “temp” shelter may be all winter shelter.

If you planned ahead for this and planted your plants in pots, then you’re good to go.

Simply move the entire plant indoors. Give it a good trim so it doesn’t wilt its foliage everywhere. Then place it somewhere that recipes some dappled sunlight.

For storage of just a few days, the garage is fine. This is good for temp dips that only last a day or two. But if you think that the cold will be for quite some time, then indoor storage is needed.

There are some things you need to know before bringing it inside. Oleander isn’t tolerant of being moved around just like that. It also doesn’t fare well indoors for extended periods, so you want to get it back outside ASAP.

When to bring oleander inside

A common question asked by readers is knowing when to move oleander indoors for the winter. The answer is to watch the weather forecast.

When your local temperature starts to hover around 20F, it’s time to start moving them in. Your plant should be pruned by now. Do some extra tidying up if necessary.

Wash the container to get rid of bugs/debris so you don’t track them into your house.

Some of the buildups may need some extra oomph to remove it. Use a sponge with some soapy water to break down the dirt. Check for bug infestations.

Then examine the dirt for crawling insects. If you get the green light, then go ahead and bring it in!

Where to put oleander for the winter

Oleander will need shelter that’s at least 40F or higher. They require bright lighting, so place them near a bright window or other sources of light.

If you have a garage with a backdoor, this can be a perfect setup.

Sheds or greenhouses can also be used for temporary shelter. Don’t place oleander heated rooms or near HVAC units.

This can dry them out or make them wilt. Additionally, place it where pets or people won’t come into contact with it. Oleander is toxic.

Caring for oleander during the winter

Please note once again, if you’re bringing it inside, make sure to keep your pets and people away from it. Oleander will be irritated.

Otherwise, enjoy those festive blooms and intoxicating aromas.

If you give it the right TLC, it’ll produce an abundance of blooms for the springtime. Then you can say you’ve enjoyed your oleander all year round, bud!

If cooler temperatures are consistent in your area, consider getting a pot that you’ll never need to replace.

This will make it much easier on yourself since you don’t need to uproot or switch pots later on. It should be able to hold the entire root system of the plant.

When the plant is sitting inside your house, reduce watering. Oleander doesn’t require much water during the winter.

Use your finger to feel the 2-3 inches of soil. Water only when it completely dries out. Use a moisture meter if you’re not sure when to water.

It’s more important to avoid overwatering at this point as pooling water will bring in pests and fungal issues.

Oleander doesn’t grow as much in the cold, so there’s no reason to continue watering it so much. It doesn’t uptake nearly as much water as it does during peak summer.

The same goes for plant food. There’s no need to fertilize it during the winter. The only thing it needs is bright light and supplemental water. That’s it. Even pruning can be forged.

Keep your plant in a dry, cool (but not warm) location from November through February.

Other than this, winterizing oleander is easy. In the early spring, you can slowly increase the light it receives and the amount of water you give it.

Fertilizing is still not necessary.

When to put oleander back outside following winterizing

Oleander should be placed back outside when the local temperature rises above 40F. Once the climate stabilizes outside, it’s time to move it back out!

Oleander, being as resilient and hardy as it is, still requires time to acclimate and adapt back to the elements outside.

It’s easy, so don’t fret.

Take the entire plant outside to a partially shaded area. Let it sit for a few hours each day. Then bring it back in. Do this for 1-2 weeks until it gets used to the “real” sun outside and then you can promote it back into the garden.

It’s imperative to watch the forecast for weather changes during this period. If you expect a cold dip, then halt the process and wait it out. If done correctly, your oleander should never experience temperatures below 40F.

Being gradual is key.

Over time, gently provide more water, light, and outside exposure to the elements. 1-3 hours per day is enough. Risking too much will shock the plant from the changing environment.

Oleanders are hardy to 35F, and some even down to 10F or 5F. But this range of cold temps is already too much for these bush plants to handle for an extended period.

For gardeners in the northern zones, they’re not too hardy and should be wintered indoors or in a sheltered location.

Set the oleander out in the late spring when the ambient temperatures are warm enough for it to thrive. Continue your regular watering schedule, give it some plant food, and enjoy those blooms.

You can encourage it to grow by supplementing it with high-quality plant food. Liquid general purpose plant fertilizer with NPK ratio 30-10-10 is excellent indoors.

Once it’s time to move it out for good, use a 20-20-20 balanced fertilizer to feed it.

Oleander dormancy

Oleander will go dormant during the winter, just like any other flowering shrub (think baneberry or forsynthia). This is normal for its natural cycle for it to properly produce.

The cooler weather will encourage leaf drop, which is normal. It’ll also slow down the production of flowers, foliage, etc. Sunlight does the opposite.

It tells the oleander when it’s time to end dormancy. Combined with warming temperatures, it’ll snap out of winter dormancy so it can continue producing.

Commonly asked questions

This section covers some questions often asked by readers. You may get some tips/tricks out of them that you can apply to your situation.

If you’re still confused about how to winterize your shrub, post your comments using the form following this care sheet.

How cold is too cold for oleander?

Oleander can handle temperatures as low as 5-10F, but this should never be practical in the real world. You should keep ambient temperatures above 40F or else you risk damaging the shrub.

This is why it’s important to winterize it for those in northern zones or if you’re outside of USDA zones 8+.

Can oleanders survive a hard freeze?

Not likely. It’ll need some protection over the winter because that is the one thing that oleander doesn’t tolerate.

Since it’s a huge plant, it can be difficult to get it under shelter. This is why people struggle with it.

Will oleander come back after winter?

Oleander is a perennial, so it’ll come back if proper care is provided.

Do oleanders turn brown in winter?

The shrub will turn brown when winter damage is present. This is common in the northern end of the shrub’s hardiness zones. Prune these parts off if possible.

Do oleanders lose their leaves in winter?

Oleander will drop leaves in the cold. This is expected when the temperatures get cooler. It’ll drop its foliage, flowers, and leaves. It may also change colors to brown or yellow from the elemental damage.

Should you deadhead?

Deadheading is necessary before you winterize your diet. There’s no reason to keep the spent flowers on the tips. Remove them before you bring them inside.

It’s ugly and serves no purpose other than bringing pests. Regularly pruning it will help get more blooms.

What is the hardiest oleander?

Nerium oleander Hardy Red is a resilient plant. It can withstand colder temperatures much more tolerable than other types.

Picking the hardiest oleander is a good idea if you’re in a cooler zone. Hardy Red produces abundances of large loose clusters of funnel-shaped flowers. It fits well inside a pot so you can overwinter it easily.

Further reading/references

• Oleander: Pretty But Poisonous – HGTV
• Nerium – Wikipedia

Winterizing oleander is easy

Now that you know everything you need to know about overwintering this perennial ornamental, do you feel more confident?

It’s not hard. It’s just the bulkiness of moving it. That’s the most difficult part, IMO.

Once you find a suitable location for it to go into winter dormancy, then it’s just giving it some water, ensuring there’s enough light, and watching out for temperature changes.

When the spring rolls around, bring it back out slowly and let it get accustomed to the outside world again. That’s it!

Got questions? Post ‘em using the form at the end of this page!~

Happy wintering. Oleander will bloom for you year after year if you give it some basic TLC.