Garden

Birch - Betula


Generalitа


Birches are medium-sized trees or large shrubs, widespread in nature in most of the temperate areas of the northern hemisphere; only a few dozen species belong to the genus, and very few are cultivated as ornamental plants in Italy; in our country there are no spontaneous birch woods, although some specimens grow in the wild at the edge of the hilly forests in the northern areas of the country; in Europe they are very common especially in the Scandinavian area.
The peculiar characteristic, which belongs to almost all species, consists of a substance, called betulina, contained in the bark, which makes it pearly white, sometimes candid. This distinctive character makes the birches very decorative, even during the winter months, when the trunks stand out in the woods, with their candid color, with dark, almost black marks. The foliage is deciduous, generally the leaves are bright green, with a serrated edge; the autumn color is yellow, but the dying foliage persists little on the tree, not giving a particularly durable color.
The stem is erect, and can reach 25-30 m in height in many species, while still remaining quite thin. The birches are pioneer trees, which means that their seeds sprout in the open field, away from the woods, and prepare the ground for the arrival of the seeds the other trees, which later will constitute the forest; for this reason birches are not very long-lived plants.
The thin branches form a crown which is mostly flame-like, elongated and not very dense; many cultivated varieties have pendulous branches, which give the tree a weeping appearance. The flowers are gathered in catkins, and the seeds are samaras, often with thin wings and little highlighted.

Birch































Height at maturity
usually 15 meters
Minimum temperature -20 ° C
Origin Europe and Asia
Soil Acid, subacid, neutral
Soil moisture Always damp, but well drained
Exposure Sun
Foliage caduco

The birches are part of the birch family, which includes some of the plants with the most famous catkins including hazel nuts, alders and hornbeams.
This family consists of 6 genera and in total more than 160 species of deciduous trees and bushes that grow, generally in the temperate-northern regions. The whole family is characterized by alternate leaves and flowers in separate catkins of which only the male ones are well evident and decorative.
The genre betula includes 30 to 60 species: short-lived trees and considered pioneers throughout the northern hemisphere.
Its name derives from the Gallic and is a diminutive of "betua". The Germanic name birch, on the other hand, has an Indo-European origin and probably means "shining".

Birch features


These are small or medium-sized trees or shrubs that are widespread especially in temperate climates. The leaves are simple and alternate, with very deep veins. Usually they are born in pairs. The fruits are small achenes sometimes with darker wings. They differ from those of neighboring genera due to the fact that the feminine fruits are not woody and tend instead to dissolve when ripe, releasing the seeds. Unfortunately, releasing a large amount of pollen is a frequent cause of allergies.
The bark of all the birches is characterized by long horizontal holes that, with time, separate it into thin paper sheets. It can take on different colors depending on the variety and age of the specimen: gray, white, black, yellow.
The buds are formed very early in the season and in mid-summer are already fully developed. They are all lateral and never apical. The wood has a very fine and silky texture and can therefore be worked very well. It is not an ideal wood to burn because it has a low calorific value.

Widespread species of BirchBetula pendula



The birch pendula is also called European birch, as it is widespread throughout our continent, up to the Caucasian areas, particularly in the areas of northern Europe; it has a thin and erect stem, with the typical candid color; the branches are thin and the twigs that bear the leaves are hanging.
The leaves are small, triangular and pointed, of medium green color. The older specimens can reach about twenty meters in height, although more often in the gardens you can see more minute trees, which do not exceed the seven meters, and often placed in small groves, consisting of two or three specimens, or stumps multiple.
There are many varieties of betula pendula, including the "youngii" variety, with all the pendulous branches, which can reach the ground, giving the impression of a large shrub that folds back on itself. The “laciniata” variety, on the other hand, has palmate foliage, subtly subdivided, almost like palmato maple leaves, but with only three leaf tips.
The white birch (betula pendula) has ovate to triangular leaves, up to 6 cm long and 4 wide, tapered at the apex, with double and coarse toothing, dark and shiny greens on the upper side, carried on slender, hairless branches, lumpy and pendulous that turn yellow in autumn. The bark is white.
As it develops it becomes dark and irregularly cleaves at the base, with age. Flowers are catkins. The males are up to 6 cm long, yellow and pendulous. The females are green, erect or pendulous, separated on the same plant in early spring. The habitat of origin is the North of Asia and Europe. It prefers light and sandy soils. It is also known as European white birch and can create large forests. It has a slightly weeping habit and can reach 30 meters in height.

Betula jacquemontii (syn. Betula utilis)




Tree of medium or small size or even large shrub, widespread in the wild in the not too high areas of Nepal and other Himalayan states; they can even reach ten or fifteen meters in height, developing in the coniferous forests. They live in areas with extreme climatic conditions, where frost is intense for most of the year. The foliage is dark green, oval, slightly widened in the center, with showy veins, yellow divenines just before falling, in autumn; the stems are erect, with rigid and well developed branches. The bark is clear, whitish or cream-colored, and tends to flake off in paper-like sheets. In ancient times, the bark of this birch was used as paper, and in fact some ancient Sanskrit writings came to us on large sheets of birch bark.

Betula nana



Dwarf birch is a shrub of small size, creeping, which does not exceed 15-25 cm in height; it develops in the arctic areas of our planet, both in Asia, in Europe, and in North America. It has roundish leaves, no longer than a couple of centimeters, with a very serrated edge, dark green, they become red in autumn, when the cold arrives; the flowers are oval catkins, about one centimeter long. It develops dense creeping branches, which give rise to large shrubs, which can cover a few square meters of land, without ever rising upwards.

Betula alba (syn. Betula pubescens)



This species of Birch is widespread in northern Europe and in northern Asia; the dimensions are greater than in the birch pendula, even if the two trees are very similar; the leaves are ovate, with a narrow margin, of a light green color, they are attached to the branches by thin branches, which hang downwards. The ancient specimens can reach 25-36 meters in height, with stems that reach up to fifty centimeters in diameter. The foliage is not very thick and the branches are quite thick; the bark is clear, cream-colored, with horizontal brown or chocolate lenticels. To the eye of the inexperienced betula pendula e betula alba they may look like the same plant, or two varieties of the same species, were it not for the different cultivation requirements; Betula alba in fact survives only in damp and cool places, with the soil often subject to heavy watering, or even often wet or soaked with water.

Betula nigra



This species is native to the American continent, where it develops in particular in Florida and in Texas, in marshy areas or areas subject to great rainfall, or near rivers. It is quite large, with specimens that easily reach 25-35 m in height, often consisting of multiple stems, with a well developed and ample central stem, and a rounded or elongated crown. Compared to European birches, this birch has a more solid and impressive appearance. The foliage is green, ovate in shape, it becomes yellow in autumn. The bark is dark, or cream-colored, and tends to flake in rigid scales, which remain attached to the stem.

Grow birch trees



In Italian gardens the birch trees that are usually planted belong to the species Betula pendula, or to a variety of it. They are fairly resistant trees, which prefer sunny or semi-shady locations; their ideal climate provides a strong temperature range between the seasons, with a very cold winter season; they can survive even very severe winters, but are instead ruined (or even killed) by long, hot summers; for this reason, they generally find a place in the gardens of northern Italy, while in southern and central Italy it would at least be appropriate to place them in shaded areas, to try to avoid the summer heat. They prefer fresh and very well drained soils, even sandy or stony, possibly with a slightly acid ph. While managing to survive even in non-ideal conditions, with stony and not very fertile soils, they tend to progressively ruin themselves if they plant a very compact, clayey or calcareous soil. They are plants that, once planted and stabilized tend not to have particular needs, do not need large watering or pruning; it is clear that the young specimens prefer watering during the summer period, and the same is also true for the adult specimens, especially if the summer is very prolonged and with very high temperatures. They can withstand short periods of heat and long periods of drought, but produce a very superficial root system, which therefore needs to be cooled off from the heat in the middle of summer, and therefore to be watered. In any case we avoid watering our birches too often, because they do not like a damp and heavy soil.

The birch in herbal medicine



Birch bark and leaves have a high content of flavonoids, which are used in medicine to improve peripheral circulation; it is therefore used in drugs against edema, to improve circulation, but also in products used to treat cellulite. Some recent studies have found that birch pulp is cytotoxic for some types of cancer, such as melanomas, but this remedy has not yet been exploited to treat this type of disease in humans.
Birch leaves can also be used to prepare an infusion, to be used as a diuretic and as an anti-inflammatory; unfortunately these leaves also contain substances that can cause allergies in predisposed subjects, and therefore the diffusion as a daily remedy is decidedly contained.

Uses and tips for the garden


Birch is famous and appreciated above all for its white bark, but also for its light foliage, which gives the garden a sweet shade during hot summer days. In autumn it takes on an interesting color. It is also a tree that is very easy to deal with and has no particular requests.
It is ideal for those who want to have beautiful and developed green spaces in a short time: it grows very quickly indeed. In 10 years it already shows a beautiful, naturally open shape.
It remains decorative even during the winter months not only for its particular bark, but thanks to its male flowers that are preserved until the appearance of the female ones, in spring.
It is very suitable for planting in groups, generally of three. However, it may also enter into a larger project that reproduces, for example, a small grove.
In general they even reach 20 meters in height, but, in recent years, dwarf cultivars have been developed suitable for smaller green corners.

Planting a birch



It can be inserted in all the gardens because it is a rustic and resistant plant. Ideal is the location in full sun. It is better to avoid only excessively calcareous and poorly draining soils. The roots remain rather superficial and develop in width, but rarely create problems for the foundations of the houses.
The best time to plant it is late autumn or early spring, especially if the plant is bare-rooted.
One must be particularly careful because the rootlets are quite sensitive and it usually takes some time to react to the plant. The more we work delicately, the less we have to wait. We try, if we can, to always buy potted plants, especially if they are young trees.
You will have to prepare a hole three times wider than the earthen bread or the group of roots. Usually 50 cm deep is sufficient. We also have a long and sturdy brace together with the plant.
The collar must emerge slightly from the ground level. Cover everything and press well. Form a small basin around the trunk and irrigate abundantly. Carefully tie the trunk to the brace.

Other tricks


Birches are undemanding trees that grow on their own and do not require treatment. During the first years it may be useful to mulch the base, especially if we live in an area with rather harsh winters or if rainfall is scarce.

Pruning


Birches should not be pruned, especially if they are to maintain their natural growth habit. So let's think about it well before planting them, reflecting on the size they will reach from adults. If we think it is excessive, we would rather focus on another tree or on a more limited variety.

Playback




The multiplication generally takes place in professional fields and is done by grafting or cutting. At the amateur level you can try with sowing, without however being guaranteed to obtain specimens identical to those of origin. Cross pollination is very common. The best time is spring. The seeds should be spread on a light and moist soil, but not buried. Everything must be kept in a sheltered and shaded corner. Spray frequently with water. Usually germination occurs within a few months and can be planted from the following year.

Illnesses


Birches are affected by various parasites of various types, but since they are resistant plants they rarely need treatment.

Uses



In northern Europe the birch bark was used for the manufacture of traditional shoes.
The wood that is extracted from it is not very calorific, but has the advantage of burning quickly and leaving few ashes. For this reason it was particularly appreciated by bakers for their oven.
In temperate areas the growth is very rapid and the wood becomes too soft. In the Scandinavian countries, on the other hand, there is a slower development and the wood gains in beauty and value. The color is white and is worked and painted very easily.
In North America, starting from the sap, a special beer is made, of wine, brandy and syrup.
The sap also possesses recognized medicinal virtues due to the contained botulinic acid.

Papyrifera birch



Papyrifera birch has ovate leaves up to 10 cm long and 7.5 cm wide, tapered at the apex, dark green on the upper side, paler with hairs on the veins from young on the lower side, turn yellow and become orange in autumn ... The bark is white with abundant dark lenticels. It flakes in thin layers of pale-orange pink immediately after detachment. The flowers are in catkins. Males up to 10 cm long, yellow, pendulous. Females are green and slender, pendulous. It is native to North America where it lives in the forest at northern latitudes. It is also known as canoe birch because its bark was used by the natives to make boats. It is the most widespread birch in the North of the United States, in Canada and in Alaska. It reaches 30 meters in height and has a high cone shape.

Japanese red birch




Japanese red birch (maximowicziana) has broadly ovate leaves, heart-shaped at the base and tapered at the apex with double and sharp serration, dark green and smooth on the upper side, carried on lumpy branches that turn yellow in autumn. The bark is reddish-brown at the beginning, then greyish-white tinged with orange-yellow and pink, with horizontal lenticels that flakes in papiraceae strips. The flowers are catkins, the males 10 cm long, yellow brown, the green females. It is native to Japan and naturally forms forests. It is also known as monarch birch. It reaches 25 m in height and has a wide cone shape.

Birch - Betula: Other interesting varieties



Chinese birch (betula albo-sinensis), yellow birch (betula allaghaniensis), birch ermanii, Japanese birch (big betula), cherry-leaf birch (betula lenta), river birch (betula nigra), gray birch (betula populifolia), hairy birch or white birch (betula pubescens), Himalayan birch (betula utilis).
Watch the video
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