Hardytropicals UK

This palm really needs no introduction. Anyone who has been anywhere with a reasonably warm summer will have seen these trees. It is the world's best known palm tree.

But a word of warning, with our winters becoming less cold this palm could be quite happy in the warmer parts of the south UK. Don't expect it to be killed off by frost within 10 years. Please remember when planting out a 2 foot £4 palm, this IS A BIG, BIG TREE! It needs 10m (33ft) of space for its crown of leaves, and the trunk, depending on how close you cut the old leaves will be between 1 - 2m (3 to 6ft)in diameter. The roots are not damaging to pipes or foundations but the trunk will break the wall of a house, therefore It should not be planted closer than 10 feet from a property.

This palm can survive -8C when large and has the potential to become a large tree in milder areas. They need a well drained soil but like plenty of water, and feed, in the growing season. Dig in plenty of grit and gravel into the planting hole and mound up slightly to improve drainage. The leaves can be gathered up as protection in winter, but beware of excluding air from the crown by covering. This can result in the central spears rotting and pulling out. Remove lower leaves as they become tatty, or if they interfere with paths etc, as the lower leaflets are spiney and can cause injury. These are removed by using a fine bladed hacksaw. Cut as close to the main trunk as possible for a smooth trunk.

Like many palms they can be transplanted even when large trees, but experience has shown that the palm will be set back, sometimes by many years, and a good few do not pull through. Palms are fiberous rooted which means the roots do not grow in width like normal trees, they grow thousands of 'little finger' width roots that search out water. When these are severed, the palm responds by sending out new roots from the base of the plant. This means they can recover although will sulk, as mentioned above. See picture of a 30 foot date palm on the move. The main problem with moving large palms is the weight. The palm in the picture may well weigh 5 or 6 tons.

The Gravesham area in North Kent facing the River Thames has quite a few Canary Island Date Palms in private gardens. Some of these are now becoming large and look like they will make good sized trees in the next ten years, weather and freezes permitting. It appears that the Thames River area has lighter frosts and many CIDP can survive unprotected even as small palms, which is generally not the case in more inland, harder frost areas.

Gravesend has a Promenade, area adjacent to the river Thames, which would lend itself perfectly to several of these trees, but currenlty Gravesham Borough Council does not realise the potential of the area for exotic planting schemes, as it's Victorian forebears did with Rosherville Gardens.

You may well ask where my super large Canary Island Date is, but I have not faired too well, with these. I have had 9 of them over the years, but not managed to keep any for more than 10 years. They are fine in pots and tubs, but are not happy planted out in the ground. Some say who am I to talk if I have lost so many, but I probably have more experience of what kills these than most.

How to kill a Canary Island Date palm ! There is a theory that soil drainage is a key to survival, but I am not convinced that, on its own, is the case. They like plenty or water during summer and can be grown well almost immersed in stagnent water. This implies the roots do not need lots of oxygen to survive, the opposite to Alocasia. Palms grown in water do well in the warmer months, but roots are likely to to rot during colder months, so it sounds more like the roots are happy in stagnent water when active, but rot if inactive. What makes the roots active? Soil temperature !. This is born out by the fact I nearly killed a CIDP by using a soil warming cable back in the mid 1990s. The cable was spiralled outwards from the trunk about 2 inches below the surface of the compost. The problem was that the cable did not have a thermostat, so was on all the time. I turned it on in December when temperatures plummeted to around freezing. After about 10 days I noticed an explosion of growth in the crown. The growing leaves and spears had grown over 4 inches at the base, but due to lack of light in midwinter this was a pale whiteish yellow colour, not dark green as in normal growth. When I measured the soil temperature it was 27C ! To me this screems out that the key to growing CIDP, and possibly many other palms, is SOIL TEMPERATURE. BUT..... then comes the downside.... The weak colourless top growth caused by high soil temperature and lack of light could not tolerate cold, wet winter conditions and promptly rotted. The whole centre rotted out - lol. This took 2 full seasons to grow out again.

So what do we know now? Cold, wet soil causes roots to become inactive and suceptable to rot. Low light, winter rain, and humidity can cause the crown to rot.

So what can we do to prevent this: Good drainage will help prevent root rot when the soil is cold, but good drainage allows the soil to cool off more quickly. Sandy soils are coldest and clay soils are warmest in winter. So a well drained mounded planting site can help but a non water retaining mulch would help retain heat. I have found pea gravel to be one of the best materials for this purpose. It stabilises the temperature, but does not retain much moisture. If soil warming cables are used to keep roots active, they should have a thermostat and be set no higher than 10C. This will keep the roots active for good health. but not promote active growth in the darker months of the year. The soil heat level can be raised during the spring to promote good growth from March onward. The light levels in March are the same as September so a soil temp of 20C would be benificial to kick start good summer growth.