Palms

The cultivation of Palms

Palms are very easy plants to grow given the basic requirements of good soil, plenty of water and protection, while tender, from full sunshine to achieve maximum growth. This is of special significance in temperate regions where the winter sun is weak and often obscured by clouds.

Any garden can support a palm or a selection of palms. The more hardy sun-lovers need an open position while the smaller types generally need more protection and can be successfully mixed with shrubs. Houses with large areas of protected garden can grow a good selection of small to moderate-sized palms and these can be complemented with plants such as cordylines, dracaenas, cycads and large ferns. With the exceptions of the largest palms, most species do not take up a great deal of room in a garden. This is especially true once a trunk is formed and the crown is elevated. Grass, shrubs or annuals can be grown right up to the base of the trunk if so desired. Palms like company and look good when planted in groups. A collection of mixed species in a suitable situation in greenhouse effect garden will always be a source of interest and conversations

Landscaping with palms

The advantage palms have over other plants used in landscaping is that their growth habit and dimensions are entirely predictable. Thus a palm can be chosen to fill a particular niche and the landscaper can be certain, given suitable conditions of soil and growth, that the palm will grow as predicted. Few other plants can be chosen accordingly.

Palms are well suited to planting as specimens in lawns or in groups, provided that they are spaced so a mower can be used between them. The palms impart an interesting appearance to a lawn planted in this way and do not interfere with the growth of the grass. Grass, provided that it is regularly watered and fertilised, will grow right up to the base of palm trunk. Mowing in these circumstances is no major problem, since a palm tree cannot be ringbarked and the mower can be run close to the trunk without damage.

Tall palms can also be planted in pairs or groups of one species or mixed with other palms or other plants. Tall palms look especially effective when planted close together in pairs, or especially impressive when planted at regular spaces to form an avenue.

Palms, especially the smaller to medium growing types, prefer company and are best planted in groups or mingled with other plants. The grouping helps create a congenial atmosphere and produces a better overall effect.

Palms provide excellent shade despite the deceptive open appearance of their crowns. A palm grove provides a shady retreat on a hot day and if combined with water features, the atmosphere is further enhanced. Because of the umbrella-like structure and predictable growth, palms can be strategically sited to provide shade for outdoor living spaces. With their generally slender trunks, palms have the added advantage of not hindering air movement or breezes while still providing shade.

Aspect and climatic considerations

Many factors are involved in the choice of a site suitable for palms. These include aspect, slope, soil type, drainage, exposure to frost, wind and sun and competition from neighbouring trees.

The aspect selected for palms will be influenced by the conditions existing in the planting are. In the Northern hemisphere a southerly aspect is generally considered most suitable.

Palms are generally quite tolerant of wind and some species are renowned for their resistance. Physical damage such as shredding of the leaves of the fan palms or entire-leaved palms can occur in strong wind conditions.

Frost greatly limits the range of palms that can be grown and most tropical species will not tolerate exposure to even light frosts. Even young palms may suffer damage to young and developing leaves, during prolonged periods of frosty weather.

Soil

Palms are not exacting in their soil requirements and will grow in a tremendous range of soil types. In fact, some palm or other will probably grow in all but the very worst types of soil. Most garden soils are reasonably well structured and fairly well drained and will support a range of palms. The better soils type, the better the growth of individual palms and the greater the variety that can be grown. Most palms seem to prefer an acid soil with a PH of between 6 and 6.5. Where soils are more acid than these levels, some correction may be necessary. Palms may grow equally well in light, sandy soils and heavier types, but the techniques of soil preparation, planting watering and mulching may differ.

Clay Soils

Heavy subsoil or clay will support hardy palms, but their establishment will be fraught with difficulty and better results will be obtained if the clay is first worked to the stage where it is friable. Clay is difficult to cultivate whether it  is wet or dry but can be improved by adding a soil conditioner such as gypsum, organic matter and/or topsoil. This mixture should be gradually worked into the clay until the structure is improved. The more effort that is put into working up such heavy clay soils, the better will be the results. Regular applications of organic matter will not only improve the friability, but will also prevent surface compaction, cracking and drying out. Also palms like soils rich in organic matter, it will greatly aid the establishment of young plants.

Light, sandy soils

Palms thrive in light, sandy soils because they are usually warmer than heavy soils (and this may be important in winter), are very well drained and aerated and are often quite deep. Such soils are often poor nutritionally however, and are usually deficient in organic matter. Heavy mulching with organic materials will help prevent this and will greatly aid the establishment and growth of young palms. As sandy soils tend to dry out rather rapidly, regular watering will be necessary, especially in the early establishment phases.

Alkaline soils

Alkaline soils have an excess of calcium salts in the soil and this creates nutritional problems with elements such as zinc, iron, magnesium, manganese. The hardier palms can be established in quite readily in such soils, however the range of suitable palms is not as great as in acidic soils. The vigour of palms planted in alkaline soils can be increased by adding organic matter to the soil surface and acidifying with sulphur.

Planting

The technique of planting palms is not significantly different from that of any other type of plant, although the correct procedure will greatly aid the establishment of the young palm.

The palms should be well soaked before planting and this is best achieved by immersion in the container in water. Pre-soaking is especially important if planting in dry times, or in dry areas. The planting hole should then be dug sufficiently wide and deep to accommodate the root system. Palm enthusiasts advocate the digging of a hole much bigger than that of the root system. Not only does the broken and loosened soil around the root system aid root penetration, but compost, organic matter and fertilisers may also be mixed into the soil. This work certainly results in rapid establishment and healthy growth, but it is a question of labour and time.

If the soil in the planting hole is dry it should be filled with water and allowed to drain before planting. Some fertiliser (either inorganic, organic, or slow release) should be thoroughly worked into the bottom of the hole before planting. About a handful is usually adequate. A good practice it to work rotted manure and compost into the soil surrounding the hole, as this aids the establishment and is of particular value in sandy souls. If planting into clay soil avoid forming a sump by digging too far into the clay.

Once the planting hole is ready, the palm should be removed from its container and dead or badly coiled roots trimmed back or straightened out. The plant should be placed in  position with the top of the container soil just below that of the garden soil and the soil firmed around the roots and watered thoroughly. The area around the plant should then be mulched.

Watering

Many palms are extremely tolerant of dryness, but all look and grow better with supplementary watering during dry periods. The shade and moisture loving species prefer plenty of water and it is very difficult to over-water them, especially in dry times.

Water is best applied during cool periods or in the evening or early morning. The best technique is to thoroughly soak the root area so that the maximum amount of water becomes available to the plant. The method of water application (that is whether by hose, sprinkler or drip system) is not of major significance to palms. Mulching greatly improves the efficiency of watering and it's application is strongly recommended.

Feeding

Palms are strong growing plants and once established are very responsive to fertilisers and manures. Large palms are gross feeders and their growth rate can be increased very significantly by heavy applications of fertilizers. Fertilisers are best applied during the warmer months when the plants are in active growth. Fertilisers are best applied to moist soil and if watering is not possible they should be applied just before, during, or after rain. They should be scattered over the surface of the ground within the drip line of the canopy.

Many growers advocate the use of organic fertilisers such as blood and bone, bone meal or hoof and horn. Animal manures are also very valuable  but should not be applied when too fresh. These materials release a steady supply of nutrients for growth and are also very beneficial to the soil. Inorganic fertilisers are cheaper and more readily available and are excellent means of promoting growth. A balanced complete fertiliser should be applied annually. The benefit can be maximised if the fertilisers applied are applied in conjunction with organic mulches.

Palms require high levels of nitrogen and two supplementary dressings with nitrogenous fertilisers each year promote growth and improve their general appearance. Suitable materials include urea, ammonium nitrate, ammonium sulphate and calcium nitrate. Nitrogenous fertilisers are best watered in soon after application.

Slow release fertilisers applied at planting will aid in the establishment and early development of a palm. A handful of such fertiliser, well dispersed through the soil in the planting hole is all that's necessary.

Pruning

Pruning of palms is generally limited to the removal of unwanted or unsightly material such as suckers, clusters of fruit of dead fronds. In a number of species the dead fronds are retained for many years and hang down as a brown skirt against the trunk. Dead fronds can be cut off regularly as they age and shredded for garden mulch, this does become a harder task as the palms become taller.

Fruits are quite a decorative feature of many palms, especially when carried en masse on the tree. On the ground, however, they are often regarded as being unsightly and in some cases messy. If this is a problem the inflorescences are best cut off early in the development prior to full production.

Bear in mind that the any attempt to cut back the main trunk of the palm will result in the death of the plant. Palms have no capacity to survive once the growing apex is damaged beyond repair and while the fronds can be trimmed back or removed entirely, on no account should the crown be touched.

Mulching

Mulching around palms, especially those which have recently planted, will aid significantly in their successful establishment. Palms are by their nature shallow-rooting plants, with a large percentage of the roots being near the soil surface. Mulching helps to keep the roots cool and the soil sufficiently moist to encourage new root growth. It's presence on the soil greatly reduces the stresses which plants experiences during hot and dry weather. And as a bonus the mulch is an excellent method of weed control.

Mulches should be applied thickly as soon as possible after planting to minimise drying of the soil surface and weed germination. After application the mulch should be watered heavily to compact the surface and reduce dispersal by wind. Although palms are fairly tough once established, the mulch should be maintained at least in the early years after planting.

A range of materials can be used as mulches for palms, but some are available only a localised basis. Mulches can include inorganic materials such as gravels, screenings, and pebbles; and organic by-products such as bark, woodchips, shavings, sawdust, peanut shells, grass hay, seaweed and so on. Extra fertiliser must be applied to palms mulched with organic materials because these substances will use plant nutrients from the soil as they are broken down, thus depriving the plants of these materials for growth.

Reclaiming unthrifty palms

While palms generally tolerate neglect well, if the growing conditions are unsuitable or severe in the extreme, plants can become unthrifty and may linger like this for many years. Nitrogen deficiency is a very common cause of this malady but other causes include poor drainage, lack of organic matter and regular periods of dryness. Unthrifty palms can be invigorated by identifying the cause and correcting it. Nutrition is the most frequent cause and good dose of a balanced fertiliser fortified with extra nitrogen will usually promote a dramatic response. A heavy mulch of some organic material should also be applied and the plants should be regularly watered during dry periods. Dead fronds should and leaf sheaths should be removed and burnt. This will expose any pests and these can be killed by spraying or natural predators.

Following these steps will usually be sufficient to promote strong new growth. If strong growth is to be maintained, however, it is essential that the fertilisers, mulches and water be applied at regular intervals.

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