When overwintering oleanders, it is essential to consider the cold winter weather conditions in Hungary. Oleanders are tropical plants and are prone to freezing in cold weather.
Last year, the oleanders survived outdoors. They are hopefully awaiting another mild winter.
Of course, there are professional recommendations for overwintering oleanders in the local climatic conditions:
- 1. Indoor overwintering: Bring oleanders indoors for the winter, or place them in a warmer location, such as a greenhouse or heated conservatory. The indoor environment allows them to avoid frost.
- 2. Protected location: If indoor placement is not possible, try placing the oleanders in a sheltered spot, such as under a covered terrace or a poly-covered shelter. This can protect the plants from cold winds and freezing.
- 3. Use of straw bales or mulch: Cover the base of the oleanders thickly with straw, leaves, or mulch to protect the roots from freezing. Proper insulation helps keep the plants warm.
- 4. Planting in pots: If you keep oleanders in pots, it can be easier to move them during winter and place them indoors.
- 5. Providing waterproof coverage: If oleanders remain outdoors, use a waterproof cover to protect the plants in winter. This can shield them from cold winds and rain and prevent waterlogging in the pots from freezing.
- 6. Choosing suitable oleander varieties: When buying new oleanders, choose varieties more tolerant to cold and resistant to winter conditions. Ask local nursery experts which varieties are more suitable for winter climates. The winter resistance of oleanders can also depend on the specific variety.
In line with these tips, three practical steps were applied:
- 1. They were placed in more sheltered locations, protected from wind and precipitation.
- 2. The pot saucers were removed to prevent water accumulation in the pots, reducing the risk of root damage.
- 3. With one exception, all oleanders are locally sourced – from various exchanges and local garden homeowners. Oleanders purchased from supermarkets and imported from abroad generally do not survive even unheated garage overwintering, although there are exceptions.
It’s important to note that the oleander (Nerium oleander) is native to tropical and subtropical regions and does not tolerate cold weather, especially frost. The overwintering conditions for oleanders living freely in Italy can differ significantly from local conditions.
Without protection against cold and frost, oleanders can be easily damaged. Snow can actually provide some insulation, trapping air beneath the plants and helping to mitigate frost damage. However, this is only a temporary protection, and freezing damage can still occur under the snow, especially if the snow layer is thin or during extreme cold weather.
Oleanders living freely in Italy generally experience milder winter conditions than in more northern countries and are likely better adapted to such conditions. However, even in Italy, there can be colder days or nights when oleanders are damaged by cold weather.
Oleanders thrive and grow best in ideal climatic conditions, and proper conditions are necessary for their outdoor overwintering. Generally, a frost-free winter temperature range is optimal for oleanders, and if temperatures drop below 0°C for an extended period, the plant can suffer frost damage.
The exact duration and lowest surviving temperature depend on the variety and other factors such as soil moisture, wind protection, etc. Generally, oleanders are more sensitive to cold, and without winter protection, they struggle to survive long-term in cold climate areas.
In Pots or In the Ground? – If Not Moved to a Protected Space
- Plants grown in pots are more susceptible to root freezing because pots cool down more quickly than the ground. Therefore, plants planted directly in the ground often withstand the cold better.
- However, an advantage of pots is that soil moisture can be more easily regulated. If the oleander is in a pot and the soil is too wet, the roots risk freezing. Excess moisture contributes to soil freezing and root damage.
So, it’s important to monitor soil conditions even in winter if the oleander is in a pot. If the soil is consistently wet, reduce watering (and ensure protection from precipitation) to prevent soil freezing and root damage. Placing an insulating layer, such as straw or leaves, under and around the pot can further protect the roots from the cold. - On the other hand, oleanders planted directly in the ground benefit from the natural insulation provided by the soil, and ground heat can mitigate harmful effects from below. However, outdoor plants can also be at risk, especially during sudden cold spells or extremely cold days. In poorly draining soil, a ground-planted oleander can suffer if freezing occurs after a rainy period, with little recourse if the soil was not protected from precipitation beforehand.
Overall, it’s important to consider the risks and benefits of both options (in pots or planted in the ground). The key is to monitor the plants’ condition, soil moisture, and adapt to the current weather conditions.