Alder Tree - General Information

The alder tree thrives in cool and damp areas such as stream and river banks, wet woodlands and marshes and once covered much of lowland Britain's vast valley swamps. Today, although the alder is still widespread and common place throughout Great Britain, only small pieces of alder swamp forest or carrs, as they are often called, remain.

The alder is a very hardy, broad leaved, deciduous, fast growing medium sized tree which copes well with a wide range of soils and is particularly suited to being planted in waterlogged areas.

Description of an Alder Tree

Alder trees can reach heights of up to 66ft if planted in suitable wet ground but tend to remain rather bushy and stunted in drier soil. With plenty of space to grow the alder has an open and rounded crown but when crowded by other trees the crown is more narrow and conical in shape.

The bark of the alder tree is a greyish dark brown in colour and fissured with a trunk that is straight and tall. The leaf buds are purple tinged, open in May and have a sticky coating on them which traps insect pests preventing them from eating the new young leaves. Once fully opened the leaves are round in shape, dark green in colour, have a leathery texture and serrated edges. By late autumn the leaves turn an uninteresting shade of brown before dropping.

Both male and female catkins appear on the same tree between February and April. The male catkins contain masses of yellow pollen which is scattered by the wind with some pollen managing to find the female catkins. Female catkins are a purple brown colour turning green after they have been pollinated. They then grow in size, become woody and form into a rounded cone. These cones protect the ripening seeds until autumn when they split open with the seeds being dispersed by wind and water.

Cultivation of the Alder Tree

Alder trees will grow in poor wet conditions and are often used in land reclamation. They will also tolerate a wide range of situations and soils apart from very dry conditions.

The alder is ideal for wildlife gardens and wild flower meadows and also makes excellent low maintenance screens and hedging.

Propagation can be done by either taking hardwood cuttings or by seeds.

Pests and Diseases of the Alder Tree

Alder trees can suffer from phytophthora, sometimes referred to as alder dieback, which is a type of fungus that causes root rot. This disease was thought to be uncommon in alders but recently a new hybrid strain has been discovered in some UK alders. Alders may also be attacked by the following pests: alder sucker and leaf mining sawflies.

Pruning of an Alder Tree

Alders should be pruned to maintain their size for your garden and to remove dead, diseased or damaged branches. Alders do need trimming seasonally to prevent them turning into a thicket of stems. If you have alder hedges, these should be trimmed during July and August.

Medicinal Uses of the Alder Tree

Heated alder leaves can be used to help with skin diseases and some people even use the flowers to make a natural soap or shampoo. Oil obtained from the alder tree's bark is used to treat aching muscles, nausea and diarrhoea.

Other Uses of the Alder Tree

Alder trees produce a wood that is soft, porous and with an ability to withstand rot under water. It has been said that most of Venice was built on alder wood piles. At one time alder wood was also used for boat building, sluice gates and for making the clogs that were once worn in the north of England. A lot of gunpowder mills once appeared in low lying river planes where there was a plentiful supply of alders, as alders also made valuable charcoal.

Today alder wood is used for making plywood, pulp and veneers.

Interesting Facts about the Alder Tree

Alder trees are surrounded in mythology and symbolism and the alder woods or carrs were considered to have a mysterious atmosphere about them. It has been said that the green dye from the alder flowers was used to colour the clothes worn by fairies and also Robin Hood.

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Trees are important for the environment and should always be taken care of. Our south west London tree surgeons have been maintaining trees for a long time and can care for yours too. Just call graftingardeners for more information.