How to overwinter oleander?

Where, when and how to overwinter a potted oleander?

Potted oleander’s hardiness is not sufficient to allow it to spend a whole winter without protection.

When to overwinter potted oleander?

Potted oleander requires no particular intervention as long as weather remains mild and dry. On the contrary, better leave it to enjoy outdoor light for as long as possible. However, when forecast temperatures reach -2°C, it is time to act.

Also note that potted oleanders need to be overwintered when climate is both humid and cold, even if frost has not yet occurred. Indeed, humidity and coolness combined can weaken the plant.

In summary, depending on year and climate of your region, overwintering of oleander takes place between mid-October and mid-November.

When to bring the pot out in spring?

You can bring oleander pots back out once risk of frost is over. Depending on where you live, removal from winter shelter happens between the months of April and May.

Where to overwinter potted oleander?

Ideally, potted oleander is placed in a cold greenhouse or an unheated conservatory, at a temperature of around 10°C.

But if you live in an apartment and your potted oleander is kept on a balcony or terrace in summer, place it in the least heated room of your home.

Indeed, oleander needs cool conditions and light in winter. Therefore, if you live in a region with very mild winters, prefer leaving your potted plant outside.

How to overwinter potted oleander?

Sheltering the plant from cold is not enough to overwinter it. Nerium Oleander requires some preliminary handling.

1. Oleander is a bush that flowers abundantly during the growing season. Before overwintering it, start therefore by cleaning it, removing all clusters of faded flowers still attached to its branches. For this use a disinfected pruning shear and protective gloves.
2. Next, scrape surface of soil in the pot with a mini cultivator to loosen it.

If you keep your potted oleander outdoors:

1. Wrap it completely in a winter fleece without bending branches (or breaking them). Tie the fleece at the base of the trunk and place the pot in the most sheltered spot on the balcony, terrace or in the garden.
2. Also protect the pot’s surface by placing a thick layer of dead leaves or flax mulch on the soil.
3. Completely surround the container itself with bubble wrap or flexible polystyrene.

Watering and fertilisation

Watering is maintained but much less frequent during the dormant season. During this resting phase, water potted oleanders moderately about twice a month. A precaution particularly important for plants in pots overwintering outdoors. Indeed, north wind tends to dry out substrate, which can lead to dehydration.

At the same time, stop all fertiliser applications.

When and how to overwinter oleander planted in the ground?

In regions with mild winter climate, such as the Mediterranean or Atlantic coast, oleander is mainly grown in open ground. When winter arrives, only the youngest specimens, or those not large enough, need protection to get through winter without trouble. Older bushes, meanwhile, are able to reshoot from the base even if their branches have been damaged by frost.

When to overwinter an oleander in open ground?

Do not intervene while weather remains both mild and dry, so your oleander benefits fully from autumn’s relative warmth and sunlight. However, monitor weather forecasts so you can act as soon as temperatures reach -2°C.

Good to know: some varieties, such as ‘Villa Romaine’ or ‘Ile de Capri’, are much more cold-hardy.

As with potted oleander, overwinter your plant between mid-October and mid-November.

© Francesco Minchiatti – Flickr

How to overwinter an oleander?

1. Place a layer of dead leaves 10 to 15 cm thick over the soil surface to protect the bush’s roots. Preferably use maple or oak leaves, which break down more slowly and therefore protect the root system more effectively and for longer.
2. Use a winter fleece and cover all branches with it, taking care to include your dead leaf mulch, and not to bend the branches.
3. Fasten the fleece at the base of the trunk and weight it down with heavy stones placed tightly together to reduce risk of wind uplift.

The following March, remove the fleece or winter cover and clear the base of the oleander of its mulch.

Watering and fertilisation

In winter, reduce watering, while ensuring roots never dry out. No fertilisation is necessary during this period.