Palm trees overwinter outdoors: 3 methods for planting palm trees

Free-range palm trees are mainly known from the tropics and subtropics, rather less from Germany. Nevertheless, empirical values ​​over the last ten to twenty years show that year-round outdoor cultivation of palm trees is no longer uncommon in this country either. But not every species is suitable for planting and especially for wintering outdoors. Whether and how a palm species can hibernate in the garden depends on various factors.

Examples of palm species

Hardy species

• Mazari palm 'Nannorrhops ritchiana' down to - 26 ° C
• Needle palm 'Rhapidophyllum hystix' down to - 25 ° C
• Dwarf palmetto palm 'Sabal minor' down to - 24 ° C
• Chinese Hemp palm 'Trachycarpus fortunei' down to - 17 ° C
• Dwarf palm 'Chamaerops humilis' down to - 14 ° C
• Blue hesperid palm 'Brahea Armata' down to - 10 ° C
• Rock palm 'Brahea dulcis' down to - 8 ° C

Not hardy species

• Bamboo palm 'Chamaedorea seifrizii'
• Mountain palm 'Chamaedorea'
• Triangular palm 'Dypsis decaryi'
• Kentia palm 'Howea'
• Date palm ,Phoenix'

Basic measures for winter protection

Protect the root area

The rougher the location, the more complex the protective measures for the root area are. You can prepare it for winter when you are planting, for example by laying a suitable heating cable in the root area.

•  Heating cables for water pipes or gutters, among others, are suitable
•  These usually have a control unit with a temperature sensor
•  The control unit starts up as soon as the temperatures drop below 5 ° C
•  There should be no risk of overheating
•  To install the cable, prepare the planting hole accordingly
•  Line the vertical walls of the planting pit with styrofoam sheets at least 5 cm thick
•  The ground remains completely free
•  Fasten the heating cable to the styrofoam plates
•  Then fill up with well-drained soil
•  Also cover the root area with bark mulch, leaves, straw or fir twigs

Tip: Everyone has to decide for themselves whether they want to take on the whole hibernation effort. Not every climate is suitable for year-round outdoor cultivation of palm trees, and even stronger winter protection would be equivalent to a heated greenhouse.

Planted palms are sensitive to frost

Even if year-round outdoor culture is not a common practice in this country, it can certainly work under certain conditions. Of course, this assumes that you choose sufficiently hardy species. Basically, frost hardiness is genetically determined and can vary slightly from specimen to specimen within the same species.

The root area and immature, growing plant tissue are the most sensitive to frost. As a result, winter protection must be adapted to the prevailing climatic conditions in order to bring these attractive plants safely through the cold season. In addition to the species, the site conditions, the age of the palm as well as the duration and intensity of a frost period play a role in the hardiness or frost. plays an important role in wintering.

Pay attention to optimal site conditions

Every type of palm has its own individual requirements for an outdoor location, i.e. temperature, light conditions, water and nutrient supply. Light and temperature cannot be separated from one another, because the higher the solar radiation, the higher the temperature level. Optimal winter protection begins with the planting. Both summer and winter conditions need to be taken into account here, because there are colder and warmer areas in every garden.

•  Warmer areas in the garden, left to the most sensitive palm species
•  Strong winds, heavy rain and snowfall, often the cause of leaf damage
•  Palms naturally need a lot of warmth
•  Prefer a sunny location outdoors all year round
•  During growth, temperatures of at least 10-18 ° C and a maximum of 20-30 ° C
•  This makes regeneration easier after frost damage
•  Other important factors are soil and air moisture
•  Moist air leaves ice crystals on the leaves
•  These ice crystals reduce frost tolerance
•  Too moist soil can cause lasting damage to palm trees
•  All year round protected locations with permeable soil ideal for wintering

Take the age of the palm into account

Young and freshly planted palms are much more sensitive to frost than older ones, especially if the frosts persist. That is why they need a little more protection to hibernate. The roots are particularly sensitive. In the case of young palm trees, they do not yet reach so deep into the ground and in the worst case scenario could completely freeze to death. As a result, they can neither absorb nor transport water, and the palm dries up. Due to their large leaf area, palm trees also evaporate water in winter and are therefore dependent on a functioning water supply even in the cold season. Older specimens are much less sensitive.

Duration and intensity of the frost period

Most palm trees planted outdoors can withstand short periods of frost relatively easily. However, not every palm species reacts in the same way to frost and every species has its own frost limit. While some require strong winter protection, others cope very well with the cold and freezing temperatures. In most cases of planted palms, appropriate protection for overwintering is only recommended during longer periods of frost.

Do not apply winter protection too early

Plant tissue that has not matured is particularly sensitive to frost. For this reason, it is important to stop fertilizing from August so that the tissue is mature before the first frosts and is therefore more resistant. When it comes to winter protection, less is often more. To prepare the plants for overwintering, they should be slowly accustomed to colder temperatures.

You can do this by being careful not to start or stop them too early. not to pack in light night frosts. Covering too early would result in the plant's frost tolerance being poor, which in turn significantly increases its susceptibility to frost. Every winter protection measure means an impairment which, in the worst case scenario, can do more harm than good to the plant. Nevertheless, one should not exhaust the frost resistance of a palm tree, this could result in massive frost damage in spring.

It is all the more important to find the right time to put on the winter protection. As soon as the outside temperatures approach the tolerance limit of the palm tree to + 5 ° C, it is time to put on the winter protection. So if a palm species can withstand temperatures between minus 12 ° C and minus 17 ° C, it should be protected from a temperature of minus 7 ° C. Depending on the hardiness of the individual palm species, more or less protection may be required.

Methods for overwintering planted palms

In mild areas

•  In regions with mild winter conditions, light frost protection is usually sufficient
•  If frost is coming, loosely tie the leaves together in different places
•  Preferably use coconut or sisal cord to tie
•  Tying them together protects the heart of the plant in particular
•  Wire unsuitable for binding, it could cut into the leaves
•  Do not tie leaves too tightly
•  There must be ventilation between the fronds
•  This prevents rot and mold growth
•  Additionally protect young plants with a fleece
•  Wrap the fleece around the leaves and stem (if present)

Older specimens can do without this additional protection in mild winter regions. On warmer, frost-free days, it is advisable to open the wrapping so that light can get inside and any condensation can evaporate. To adequately protect the root area, cover a large area with a thick layer of mulch, dry leaves or straw.

Tip: Snow on the fronds generally has an insulating effect. Nevertheless, its weight can cause the fronds to snap off, which is why it should be shaken off the plant to be on the safe side.

In locations with moderate frosts

In order to overwinter in cooler regions, the fronds are loosely tied together again with appropriate cords. The space between the fronds can be filled with dry leaves or straw to protect the heart even better. Simply tying them together is not enough, the leaves must also be wrapped with an air-permeable frost protection fleece, reed or bamboo mats. The whole thing is loosely fixed again. Depending on the type of palm, this wrapping should also cover the upper end of the trunk. The casing should be opened or closed on several consecutive days without frost. removed and the plant aerated.

In regions with severe frost

In areas with constant strong frost, a planted palm can only be overwintered with a relatively large amount of effort. Sheathing and covering alone is not enough here. A temporary protective structure, which you can build yourself from a few wooden posts and styrofoam, for example, can provide sufficient protection. It is particularly useful for specimens that are no taller than 2.40 m.

You need four sturdy wooden posts that are knocked into the ground around the palm. The easiest way to do this is to sharpen it a little beforehand. The upper ends are connected with boards of the appropriate length. Hard foam panels (Styrofoam or Styrodur) are then screwed all around to this framework. The plate on the roof is only placed loosely and weighted down with stones or the like. If you use commercially available wing screws to fasten the panels, especially on the south side they come off more easily if you open the construction a little when the weather is nice and ventilate the whole thing would like to.

Tip: Regardless of the type of winter protection, as soon as frost is no longer expected, it should be removed immediately. Otherwise, fungus and rot can occur under the cover.