The laburnum is a small deciduous tree originating from central and southern Europe, which also spread to Asia and some parts of central and northern Europe; it has an erect stem, sometimes lithe, and reaches 6-10 cm in height. The foliage is oval, quite disordered, the bark of the stem is grayish brown, smooth and silky in appearance, the branches are gray, smooth. The foliage is pinnate, consisting of three small oval leaves, light green, with a gray or whitish underside. In late spring, generally in May as the common name of the plant suggests, it produces long clusters of golden-yellow flowers, of a papilionaceous type, reminiscent of the inflorescences of wisteria. The flowers are followed by the fruits, long dark pods that contain the small fertile seeds, similar to brown peas. These very elegant trees can be placed in the garden, even if they are easily found even in nature, in the mid-altitude alpine areas. L. alpinum is also present in the mid-altitude alpine forests, which is more resistant to cold.
The Laburnum anagyroides prefers sunny locations, does not fear the cold, but may fear excessively hot and dry climates, such as those in the southern areas of our peninsula. There are also hybrid varieties, also suitable for places with very hot summers, such as Laburnum x watereri, with very abundant flowering. The seeds of the laburnum they are poisonous wharves, so it is advisable to avoid planting these plants in places very frequented by children or by grazing animals.
The plants of laburnum planted for some time, with a well-developed root system, they are satisfied with the rains; the young trees recently placed at home must be watered during the summer season, always waiting for the soil to be dry between one watering and another. In autumn, bury at the base of the plant mature organic fertilizer, or slow release granular fertilizer.
The laburnum is a plant that prefers loose and deep soils, preferably calcareous, very well drained; it tends to adapt quite well even in areas that are not exactly favorable and primitive. The laburnum is in fact a plant belonging to the genus of the Fabaceae, a group of plants characterized by very special roots, which with their activity are able to improve the quality of the soil in which they are found.
In fact, Fabaceae have particular bacteria on the roots that, thanks to a special symbiosis with the roots, can produce nitrogen. Nitrogen is one of the most important organic substances for plants, one of the most used in the growth and formation of new tissues.
The multiplication of the laburnum anagyroides it happens by seed, in spring; the seeds are fertile only after scarification, before being buried it is advisable to pass them with sandpaper, to favor the penetration of water into the seed and allow the shoot to develop. In summer it is possible to practice wood cuttings with a good success rate.
Pests and diseases
The laburnum is a very robust plant that is generally not attacked by pests or diseases and there are no particular problems of any kind at the moment.
The laburnum anagyroides It is called Laburnum jargon due to the spectacular deep yellow flowers that it produces in the month of May. The morphology of these flowers is typical of the Fabaceae, with very characteristic petals similar to those of wisteria, ryegrass, robinia and other plants of this genus. In the months of flowering it is impossible not to notice the bushes and plants of this splendid plant turning in parks and hills.
In the mountains there is a more rustic and resistant variety of this species, the alpine laburnum, very similar to the laburnum normal but more resistant to cold and to the typical excursion of the mountain belt.