Some palms are some suitable for planting outdoors in the British Isles. Hardy palms are invaluable as structural plants in tropical-style gardens and look effective when planted with bamboos and New Zealand flax. In pots they can form striking architectural features on the terrace.
Position and planting
Hardy palms will survive winters to -10C in southern Hampshire. However, plants that are in exposed positions, in containers or wet at the roots will be more liable to winter damage. As a result, the temperatures quoted are a general guide only – and the term hardiness is applied to mature specimens as young plants are more liable to being damaged by cold weather.
- Palms can be grown in containers of John Innes No 3 compost. Ensure that polystyrene or broken crocs are placed at the base of the pot before filling with compost to ensure good drainage.
- Hardy palms can be planted out in the garden in a sunny position and in well drained soil
- Plant in mid-spring to allow time for the palm to establish before winter. Choose a well-drained spot in a sheltered position as few palms tolerate windswept locations
On heavier clay soils prone to winter waterlogging, thoroughly cultivate a wide area, adding grit, sharp sand and compost, and build up the soil into a low mound 25cm (10in) high. Planting into the centre of this mound will keep at least some of the roots above the saturated soil in winter.
Palms grow slowly and need adequate space as they do not compete well with surrounding plants and most are not tolerant of shading.
As the palm stems thicken with age, the plants become more tolerant of lower temperatures. Prolonged winter frosts and cold winds damage leaves and may kill the central growing point. Where cold winters occur, prepare plants with a protection wrapping
Palms grown in containers should also be protected or brought under cover for the winter. Where containers are left outdoors, ensure the pot is bubble-wrapped to prevent frost damage to the roots.
Pruning and training
Unlike other trees, palms cannot be pruned. However, unsightly dead lower leaves can be removed; but do not cut them back flush with the trunk.
Feeding and Watering
During the winter most hardy palms are effectively dormant and require little care. Once the growing season is underway you should water your palm periodically to prevent it drying out, especially palms grown in containers. To keep your palm in good condition, apply fertiliser Vitax Q4 in April and July
In most parts of Hampshire and during an average-to-mild winter, the more reliably cold hardy species (Trachycarpus, Chamaerops, Brahea, etc.) should be fine left to fend for themselves without protection, as long as they are of a reasonable size when planted out. In the cooler parts of the county and during unusually cold winters it is advisable to tie the fronds of the palm together and wrap the whole plant with several layers of horticultural fleece or hessian during the worst of the winter cold. Potted specimens should be moved into a shed, garage or unheated greenhouse
Fairweather’s Top 8 Hardy Palms
Chusan Palm or Windmill Palm – Trachycarpus fortunei
Trachycarpus fortunei are one of the most cold hardy Palms available. The Chusan Palm Tree has:
- Leaves that are arranged into symmetrical crown that is about 8 to feet wide.
- Trunks that are usually covered with a loose mat of coarse grey or brown fibre and can grow to heights of 20 to 40 feet.
- Tolerant of clay soils and some shade
- Slow rate of growth
- Hardy to -15C
- RHS Award of Garden Merit
Jelly or Pindo Palm – Butia capitata
Butia capitata, the Jelly Palm can grow up to 20 feet and has:
- Long,arching, feathered leaves
- Leaves ranging from light green to bluish grey and growing 5 to 10 feet long.
- The trunk normally reaches 12 to 15 feet with a diameter of 1 to 15 feet.
- Enjoys a sheltered site but will tolerate some clay
Mexican Fan or Petticoat Palm – Washingtonia robusta
Mexican Fan Palms (Washingtonia robusta) have many fine attributes including salt resistance and a fast rate of growth. The cold hardy Mexican Fan Palm has a slender trunk topped with crowns of large fan-shaped evergreen fronds
Reaching40-50 ft (15 m) in mild areas, this palm is a striking sight. Mexican Fan Palms have:
- A grey trunk ringed with closely set leaf scars although usually at least part of the trunks remain covered with dead leaves that hang in a thatch.
- The solitary trunks, about 10-12 in (25-30 cm) in diameter, bulge at the ground and become slender as they approach a crown of large palmate leaves with gracefully drooping leaflet tips.
- Will tolerate some shade
Mediterranean (European) Fan Palms (Chamaerops humilis) have beauty, ruggedness, versatility, cold hardiness and drought resistance. Cold hardy Mediterranean Fan Palm trees are also fairly fast growing when supplied adequate moisture and fertilizer.
Mediterranean Fan Palm – Chamaerops humilis
Mediterranean Fan palm trees’ leaves are arranged in a symmetrical crown that can reach 8 to 10 feet wide and 8ft tall. Mediterranean Fan palm trees have:
- Triangular, fan shaped leaves
- Leaves ranging in colour from blue-green to grey-green to grey-yellow.
- Multiple trunks surrounding the main trunk in more mature plants
- Europe’s only native palm is hardier than most
- Leaves maybe trimmed up the trunk to highlight the plants structural form
- Great in pots or planted in the ground
Blue Mediterranean Fan palm – Chamaerops humilis var cerifera
Native to the Atlas Mountains of Morocco the Blue Mediterranean Fan Palm is similarly robust, taking, when established, any degree of drought or wind and are, if anything, slightly more hardy to cold than their plain green cousins. Also valuable in the hot, dry conservatory where they will take any amount of heat. Height 3m Spread 2m
Dwarf Mediterranean Fan Palm – Chamaerops humilis Volcano
Native to Etna, Sicily this is a selected dwarf form of Chamaerops humilis so is slower growng, shorter in stature, and has smaller stiffer leaves. As with its bigger cousin, Chamaerops humilis ‘Vulcano’ is variable in the actual size and form of the leaves and, especially, the degree of silver on the leaf underside. Mature plants of this cultivar are especially beautiful, possessing a compact symmetry that is lost when the form is expanded. A choice garden palm!
Mexican Blue Palm – Brahea armata
A slow growing palm, the Mexican Blue Palm eventually forms a fat 45cm thick trunk topped by stiff, powder blue fan leaves, the central point of which points downward. Brahea armata is a wonderfully bright accent plant for a sunny sheltered garden. It also makes a wonderful palm for a hot conservatory as it is able to tolerate a position in full sun with dry air.
Height 2m Spread 1.5m. Hardy to -8C or lower if kept dry
New Zealand Cabbage Palm or Torbay Palm – Cordyline australis
Naturally a tall single trunked or branched tree Cordyline australis rarely reaches giant proportions as, inevitably, it will be cut back by cold, but will usually re-sprout from the base and quickly regain some size. Undemanding and tolerant of wet salt-laden gales as much as the parched dry conditions, Cabbage trees quickly grow into architectural specimens. Vast spikes of scented flowers in late summer can fill a garden with perfume – resultant seed laden trusses help birds through winter.
Remove lower yellowing leaves as required. Height 5m Spread 1.5m.