Which palm tree to choose for your garden?

Before setting your sights on a particular species of palm, it is absolutely essential to take into account certain selection criteria since this tree plant is intended for a cultivation in the ground. Choosing an outdoor palm tree is therefore not done lightly if you want it to benefit from excellent conditions to develop without problem. Let’s see what are the two points that must be taken into account when buying a palm tree.

Choosing an outdoor palm tree according to the climate

The climate is the most important criterion something to consider before buying a palm tree to plant outside. Fans of the genre rest assured: there are about 2,500 species. Whatever region we live in, there are therefore inevitably palm trees capable of adapting to it. To choose well, you must learn about the hardiness of the species because not all palm trees tolerate frost. Fortunately, there are still some that easily withstand very low winter temperatures.

Note that palm trees can be classified into three categories quite distinct, namely:

  • Rustic palms : they tolerate temperatures below -6 ° C,
  • Moderately hardy palms : they are more adapted to a culture in the regions of the south of France as well as along the Atlantic coast,
  • Non-hardy palms : they do not tolerate negative temperatures and some can even be seriously in danger of death below 10 ° C, as is the case with some tropical palms.

It is therefore clear that if a very cautious palm tree can only appreciate the Corsican climate, for example, it should absolutely not be planted in a garden located in Lorraine.

In addition to the current temperatures in winter in its region, it is also necessary to consider the precocity of the frosts, which can be rife as early as November, the duration of the periods of frost, the frequency of late frosts that is to say in April or in May. Finally, very wet winters are not to the taste of all palm trees either.

Types of climates and hardiness zones in France

here are the different types of climates in our country, this one being further divided into hardiness zones (from 6 to 10) or USDA zones (US Department of Agriculture to which we owe this concept of geographical division). These zones were defined according to specific climatic conditions, namely the average, over the last 20 years, of minimum temperatures in winter. It is very interesting to keep these indications in mind when deciding to choose a palm tree.

  • Type 1, mountain climate, Zone 6a: -23.3 to -20.6 ° C.
  • Type 2, semi-continental climate and mountain margin climate, Zone 6b: -20.6 to -17.8 ° C.
  • Type 3, degraded oceanic climate of the central and northern plains, Zone 7a: -17.8 to -15 ° C.
  • Type 4, altered oceanic climate, Zone 7b: -15 to -12.2 ° C.
  • Type 5, frank oceanic climate, Zone 8a (-12.2 to -9.4 ° C) and zone 8b (-9.4 to -6.7 ° C).
  • Type 6, altered Mediterranean climate, Zone 9a: -6.7 to -3.9 ° C.
  • Type 7, South-West Basin climate, Zone 9b: -3.9 to -1.1 ° C.
  • Type 8, frank Mediterranean climate (Corsican coast and extreme south-east), Zone 10a (-1.1 to 1.7 ° C) and zone 10b (1.7 to 4.4 ° C).

It is strongly recommended that the gardener always refer to these different very precise data, before buying plants, especially if he lives in an area considered extreme in terms of climate.

Choose a palm tree suited to the size of the garden

Some palms reach moderate size in adulthood while others grow gigantic within a few years. To keep some consistency the dimensions of the tree must not be disproportionate to those of the ground. A palm tree should never be a nuisance.

As a guide, here are some examples of palm trees to plant outside. North of the Loire, it is possible to cultivate a palm tree that is very resistant to cold. Among the hardy palms that perfectly tolerate low temperatures, we find for example:

  • Chamaérops humilis : a pretty bushy dwarf palm with a compact base, which measures in adulthood approximately 4 m width and height,
  • Trachycarpus Fortunei : it is the Chinese palm nicknamed the hemp palm, whose stipe (trunk) does not exceed 30 cm in diameter in adulthood, but this specimen still reaches a height of the order of 15 m,
  • Phoenix canariensis : it is the palm of the Canaries sometimes called false date very common on the French Riviera. It should only be grown in areas where winter temperatures do not drop below -7 or -8 ° C. With an average height of 12.50 m and a wingspan of 8m, it can only be suitable for a large area garden.
  • Washingtonia filifera : known as the California palm, it is also called the petticoat palm. Native to Mexico, it presents an interesting hardiness since it can withstand -12 ° C provided the soil is dry. It grows fairly quickly and reaches a maximum height of 17 to 18 m for a width of 5 m.
  • Rhapidophyllum hystrix : it is the needle palm or porcupine palm. Very rustic, it braves temperatures in the order of -25 ° C without flinching. It forms a tuft of about 1.60 m high for a maximum of 2 m wide. It is therefore well suited to a small garden.

Obviously, in our regions with mild winters, every gardener can choose any species of palm tree, but always taking into account its dimensions once adult. In any case, when buying a palm tree, it is necessary to make sure with the grower that the desired species can indeed be planted outdoors in the USDA zone concerned.