Alnus incana Laciniata - Grey Alder

Alnus incana 'Laciniata' is a particularly elegant variety of white alder. This deciduous tree, with a medium-sized stature and a slender crown, bears fine-textured foliage composed of toothed leaves. Its smooth, almost white, grey bark, adds to its charm, as does its winter flowering with pendulous brownish-purple catkins, which appear well before the foliage. This tree is very hardy and not very demanding in terms of soil requirements. Well adapted to moist and limestone soils, it can withstand drought once well rooted. It can be planted as a standalone specimen in a medium-sized garden or on a large plot of land.

Alnus incana 'Laciniata' is a deciduous tree belonging to the Betulaceae family, just like birches. The species, commonly known as mountain alder or grey alder, is native to temperate regions of the northern hemisphere and is hardy down to -36ºC. Thanks to its flexibility and ability to produce suckers, it is one of the few trees capable of withstanding avalanches. It is a pioneer species, with rapid growth and the ability to form dense stands in poor and limestone soils. Its deep and running root system allows it to withstand wind and establish itself firmly even in very unstable, sloping terrain.

The 'Laciniata' white alder reaches a height of 10 to 12 metres and a spread of 5 to 6 metres. Its growth rate is moderate and depends on the growing conditions. This variety often develops multiple trunks, giving rise to a slender main branch supporting an elongated ovoid crown. Both the trunk and young branches are grey. The deciduous foliage appears in spring and falls in autumn. It is airy, light green and composed of widely spaced leaves with deeply serrated edges. The branches and undersides of the leaves are covered in a light fuzz. Flowering occurs in February. The tree bears inconspicuous female catkins, measuring about 5 cm long, and more decorative male catkins, measuring 7 cm long, with a purplish colour and powdery yellow pollen. Once pollinated by insects, the female flowers transform into fruits. These are grey-brown cones, visible from September onwards, remaining attached to the branches throughout winter. They release narrow-winged seeds that are dispersed by the wind and provide an important food source for certain birds. The 'Laciniata' variety tolerates occasional flooding better than the typical species, but its cousin, the common alder, is better adapted to marshy soils.

Alnus incana 'Laciniata' is a highly ornamental tree, best placed in a clear location to fully appreciate its natural elegance. Surround it with low-growing shrubs that thrive in limestone soils, such as dwarf weigelas or St. John's wort, for example.

White alder is widely planted for greening poor and unstable soils in mountainous areas, as well as on slag heaps. Its root system forms nodules containing nitrogen-fixing bacteria, enriching the soil with this valuable resource. It is also commonly used in windbreak hedges in flatlands.

Alnus incana comes from the Latin word incanus, meaning "covered with greyish-white hair," referring to the hairy undersides of young leaves. The leaf is used as a diuretic and vermifuge. The bark is astringent and tonic.