When to use winter protection?
During the winter, we receive many questions about frost, winter hardiness and winter protection. Topics that are different for every situation. That is why we try to shed more light on these questions in this article.
We briefly discuss how each species should be cared for in winter. If that is not enough, below you will find a manual for wrapping your palm or tree fern in winter.
Take heed of the combination of wind and frost. A plant prefers a crystal-clear night with -12 dan two days of -8 in combination with an eastern wind with wind force 6, The chill temperature (the ‘felt temperature’) would drop much lower. Because of icy winds, plants can also damage due to droughts. If we would get dry lips due to the cold weather, expect plants to suffer as well.
Tree ferns can dry out completely due to frost. Most people think the plant cannot handle the cold, but the drought caused by the cold is much more dangerous, especially with eastern winds.
In short: the reason why we conservatively say protect from … instead of hardy until a certain temperature is due to the fact that a minimum temperature does not say as much. Additional aspects play a role as well, such as:
- Is there a thick layer of snow? (Could work isolating for the soil, but that does not apply when the snow is located on top of the leaves.)
- Does the temperature drop early in morning to a far minimum with sun during noon or is it that temperature for many nights without sun during the day with temperatures around 0 degrees?
- Is the cold combined with dry (eastern) winds or is there no wind at all?
- Given temperatures on our site are meant for plants in full soil. A potten palm or plant is more vulnerable, as a pot can freeze completely. During a frost of -10 for two days long, this frost creeps into the soil for about 10-15 cm deep; this could still mean the roots are left unharmed. This is different in a pot.
For years, I have had to point out to customers that certains plants are not winter hardy and that is is better to keep them as a potted plant. I often receive the reply ‘Ah, but we do not get these low temperatures anymore’. You only need 1-2 nights of a cold snap to damage your beautiful plants if they are not protected. As we have not had cold winters for the last few years, I expect many people to be taken by surprise. Preventing is better than curing, so to help you out with your plants, you can find a few useful tops below. That way, you will be more prepared. Some plants are too beautiful to neglect, so make sure to give them the extra effort.
Specifics per plant species:
With for example Musa basjoo and Musa sikkimensis, the trunk will often stop growing at -5; instead, they will continue from below (if no protection is used). Some people put a pipe or something similar around the trunk and add hay to protect it, but if temperatures drop to -10, they will not continue growing from the trunk (and instead, grow from below as well). It is very important to use old leaves (prefered oak), wood chips, old blankets, pine branches or anything similar, to protect around the area around the trunk. That way, you will protect the underground rhizome against frost, so it can continue to grow in spring. Bear the tips for potted plants above in mind if you have a potted banana.
Dicksonia antarctica and Cyathea australis can handle quite some frost. The leaves will turn brown at -4/-5. Cut these off at around 20 cm from the trunk. The vulnerable part of a tree fern is the crown. Put as much hay or leaves as possible in the crown to protect it. Proceed with wrapping climate cloth or old blankets around it. Finish it off with bubble wrap and tape; do not forget to surround the bottom of the trunk for another 30 cm to protect the roots. This is only possible with tree ferns. Never use plastic or similar non-breathing materials with palms.
Try relocating palms in a pot to a sheltered location. Put them closely together and make sure to protect the pots a swell. A frozen pot with a palm/plant in full (eastern) wind will quickly dry out your plants as the roots cannot continue their sap stream.
It is recommended to apply some mulch around the trunk. Many people in colder areas use our root protection as well.
It is important to bind the leaves together. The most vulnerable part of a palm tree is the spear. Do not just protect the leaves but also the top of the trunk (around the spear). You can use winter protection, climate cloth, a reed mat or similar around it and to finish it off with a blanket around the whole.
Olive trees are often potted; try to relocate the tree to a sheltered location and protect the pot. To protect the leaves, you can apply winter protection, climate cloth or warm blankets. It is especially important to protect the leaves if it is windy.
I hope, without inducing fear, that I have been able to contribute to a solution against the cold that is setting in quickly.
Applying winter protection
We're frequently asked on forums for tips on how to best get your palms and exotics through the winter. So here are a few guidelines for you; follow these and you'll be able to enjoy your garden right through next year.
A tropical garden can look great in the winter, by the way!
- Scatter Winterhardy from the start of september until the end of October at the latest. This is a high-quality strengthener for you plants which thickens the cell walls. It's an ideal, well balance formula which ensures that Calcium and Magnesium phosphate are asborbed correctly and will get your plant through the winter. Prevention is better than cure!
- Gardeners often take great care to protect the leaves but forget the root system! A palms really depends on developing thick, new roots which are continually developed from the trunk. Because of this, the roots are often close to the surface. Trachycarpus fortunei roots can be damaged from around minus 8 degrees Celcius; as such they are more vulnerable than the leaf-crown! A frequent mistake is to unpack the palm while the roots are still half-frozen. In doing so the plant becomes susceptible to drying-out as the roots are unable to absorb water. Potted palms are also certainly vulnerable and should be protected at temperatures of -8C or more with our, winter protection for pots. To prevent root damage by frost, it's advisable to mulch well around the base of the plant and to cover with our special root protection.
- After that, bind the leaves together. Palm leaves can go quite a while with little or no light. Choose a soft string to bind the leaves, so that no damage occurs to the stem or leaves. We recommend elastic plant binder.
- In my experience, rolls of Climate Cloth for Plants provide the best winter protection of all. This synthetic climate-cloth will not take up water where, for example, normal felt will absorb water after a while. It's more 'airy' and is less prone to developing mould. It can be wrapped as you wish and can fit any form of plant.
- You can cover the whole with one of our plant covers or protectors. A reed mat works well and looks at home in the garden.
- A palm tree needs to generate new roots from the base of it's trunk so that the leaf crown can be fed and developed. That's why it's important to encourage good and rapid growth in the spring. By removing the mulch layer from around the trunk on time (the ground beneath it is not frozen), you can unpack the leaves earlier and the ground around the trunk will warm up more quickly. It's then a good idea to pour palmbooster round the trunk to stimulate the roots further, because without roots the palm can't absorb nutrients.
Protecting tree-ferns and other sensitive exotics
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- Use ample synthetic climated cloth particularly in the crown of the plant.
- Supply a good supply of mulch around the trunk.
- For Cyathea species, sensitive Dicksonia species and sensitive palms use self-regulating heating cables. These are available in various sizes and have inbuilt thermostats which ensure targeted heating. This means energy efficient. We also have cheaper warmth-cable which you can attach to a seperate thermostat.
- It's important to cover the mulch layer with a root protector and maybe bubble-wrap too.
- You can cover the whole thing with a plant cover or reed mat.