Scanpalm - Washingtonia (English)

Washingtonia robusta, Mexican fan-palm, can be categorized likewise as Jubaea chilensis when it comes to the demands for mild winters, but it will need warmer summers. Small individuals of Washingtonia robusta will suffer badly if the temperature goes down to -5 °C, especially if the cold-period's length lasts for days. Plant as big individuals of this palm as possible, because large individuals are considerably hardier. Old and established palms can manage temperatures down to -8 °C, even though the cold lasts for some days. However, this depends on the matter of humidity. If the temperature drops down below -10 °C, mature and established individuals will begin to suffer noticeable. The leaves will suffer badly in such conditions.

The palm is a fantastic sight, especially in windy conditions because of the gracious waving. Washingtonia robusta can reach 30 metres in height. This makes it easy to understand why the trunk has to be elastic and the leaf-crown rather small. The leaves get normally not longer than 2 metres in length. Today you can find enormous and gracious individuals along Venice Beach and Santa Monica Beach (Los Angeles), which is probably something most people have seen in various Hollywood-productions.

Washingtonia robusta can be planted close to the sea, because of its salt-tolerance. The palm likes to be in the sun, but it can handle shadow fairly well. Arid conditions are no problem, but the speed of growth increases with some water in the soil. In the winter, the palm should have very little water. Protecting the palm against the rain could do this. The combination between humidity and frost is very bad. Good drainage has to be arranged. W. robusta will grow much slower in Scandinavia than in warmer areas, where it is rated as one of the world's most fast-growing palms. Washingtonia robusta produces seeds that germinate quickly, and the germination rate is quite high too.

The palm has demands that are hard to meet in Scandinavia, which will restrict the extensiveness. Suitable areas of growth are to be found along the western coast of Norway, and perhaps in the mildest areas of Denmark. The speed of growth allows the garden centres to grow these palms fast, which result in low prices. Unfortunately it is very rare to find W. robusta in Scandinavian garden centres, because it is difficult to grow outdoors in Scandinavia and the fact that it is not suitable as an indoor-palm.

Washingtonia filifera deserves to be mentioned. It is rated slightly hardier than Washingtonia robusta, but exactly how much is uncertain. Established individuals of Washingtonia filifera can handle temperatures down to -10°C, if the cold periods length does not last more than a couple of days. But as with W. robusta, low temperatures can only occur in arid conditions. Washingtonia filifera is known for fast recovery after cold periods.

The palm is very adaptable, which is easy to understand if you see the various environments and climates that it can be located in. The palm can handle arid conditions combined with extreme heat and cold. The pH-value has little impact. W. Filifera can be found growing in pH-values ranging from light acid to high alkaline (some places the pH-value is 9!). W. filifera does not need as much sunlight as W. robusta. It manages fairly well half-shadow, but the temperature demands rise. If you look at the big overall, W. filifera and W. robusta have mainly the same temperature demands concerning good growth, but W. robusta needs slightly warmer summers to build up the hardiness.

W. filifera cannot grow so tall as W. robusta, but still it can reach fabulous heights as 20 metres. W. filifera has longer and harder leaves than W. robusta. The leaves on W. filifera have more space between them than the leaves on W. robusta. W. filifera does not have the characteristic thorns, which can be found on W. robusta.

Washingtonia filifera has little possibilities of great extensiveness likewise as Washingtonia robusta. W. filifera should be tested in the areas where W. robusta should be tested, and in some bigger scale around these areas. W. filifera could perhaps manage the mildest places in South-Sweden.

Pictures:

Washingtonia robusta, Lanzarote summer 2003 and Washingtonia filifera Costa Daurada summer 2005

(Photo: Thomas Vestre)

External links:

Interesting article about a Washingtonia growing from seed to a large palm tree

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More pictures:

Costa Daurada - 2005

Menorca - 2006

Gran Canaria - 2007

The French Riviera - 2008

Santorini, Greece - 2008

(Photo: Thomas Vestre)