Black Alder, Alnus glutinosa, botanical description

Botanical sheet dedicated to the black alder, Alnus glutinosa

The black alder: a species for river banks

The glutinous alder, Alnus glutinosa, is a deciduous tree which fixes the banks, cleans up and enriches spongy soils and captures nitrogen (thanks to nodosities present on the roots) for its own benefit; it is therefore the typical tree of the banks of watercourses and marshy areas. Very common in France (except in the Mediterranean region), it is a very popular subject in eastern France. It is a species that requires light and has difficulty with competition from other trees: it needs a large living space.

Description of the black alder

The alder, sometimes called alder or worm, has a deciduous foliage with a rather dense cover. Its top is conical, its branches erect (almost horizontal), and its male flowers (long hanging catkins) and female flowers (short erect catkins) are borne by the same individual. The pollination is done by the wind.

The bloom, during March, is discreet and precedes the exit of the leaves. The fruiting composed of small cones (the strobiles) is regular and abundant.

Of very fast growth; the black alder has a longevity comparable to that of the man; it lives between 60 and 80 years.

The enemies of the black alder

Microscopic fungi carried by the waterways cause root rot, the outcome of which is fatal.

The black alder is also sensitive to deer rubbing (marks that deer make on the trunks by rubbing their antlers).

The qualities of the black alder

The black alder is not afraid of water; it is rot-proof and has often been used for the construction of foundations, water pipes or pilings. The city of Venice is built on alder piles.

The wood of the black alder is orange in color. It is light and soft, easy to work. It is very often used in turning and furniture.

Growing tips

Alder should preferably be planted in deep soil, along waterways. It has a high water requirement and tolerates well asphyxiation by flooding.

It tolerates soils with a pH ranging from neutral to very acid.

Demanding in light, its fast growth compensates for its weak longevity.

The Canadian Cercis, cultivation and maintenance

The Canadian Cercis: beautiful flowers and leaves

Cercis canadensis is a small tree native to North America with undeniable aesthetic assets: elegant foliage for 8 months of the year and, just before the leaves appear, a beautiful purplish-pink bloom that appears on the entire plant, including the trunk (cauliflora).

Weeping and erect cercis

There are two types of cercis du Canada. The weeping ones (ex.: Cercis canadensis 'Ruby Falls' - 2 meters high), and the erect ones. Of the latter, there are different colors:

• Cercis canadensis 'The Rising Sun': young golden orange leaves, then yellow, green and finally orange in autumn.
• Cercis canadensis 'Merlot': bright purple leaves.
• Cercis canadensis 'Carolina Sweetheart': young pink-red leaves that give way to a mix of dark green, creamy-white, pale yellow and pink tones.

Cultivation of the Canadian Cercis

Canadian cercis are hardy trees (up to -25°C) that are reasonably resistant to drought. They are planted in spring or autumn, by adding compost to the planting hole, not forgetting to install a stake so that they can root properly, without moving. We finish the plantation by installing a mulch in order to limit the evaporation of water from the soil.

Pests and diseases

Canadian cercis are rather resistant. However, a few small caterpillars may nibble on a few leaves, but nothing to worry about.

Advantages of the Canadian cercis

• A beautiful colored foliage from April to October / November, depending on the region;
• An interesting flowering range, from the beginning to the end of April, depending on the region. Most often purplish pink, the flowers can also be white (Cercis Canadensis 'Vanilla Twist' with a weeping habit, very floriferous), single or double.

Pruning Cercis Canadensis

Cercis are pruned after flowering.

• Weeping cercis can be pruned to encourage branching, but this is not mandatory.
• The erect cercis are pruned to promote branching or to maintain the tree at a 'reasonable' size, knowing that they are, in any case, small trees that reach, at 10 or 15 years, a height of 3 to 4 meters.

Hornbeam, Carpinus betulus : botanical card

Botanical sheet about hornbeam, Carpinus betulus

The hornbeam is the most widespread tree in France, especially in the plains and plateaus of the north and east of the country. It is often confused with the beech, which it differs by its toothed leaves and its fluted trunk.

Description of the hornbeam

The hornbeam is a forest tree that can live between 100 and 150 years. It grows slowly and can sometimes reach 20 to 25 meters in height. It is a species that appreciates semi-shaded exposures and tolerates well the cover of large trees.

The dense deciduous foliage of the hornbeam falls late in the winter. The male and female flowers (catkins) are distinct and grow on the same tree (monoecious plant). They bloom during the months of April and May and it is the wind that ensures the pollination, as well as being responsible, thereafter, for the dispersion of the seeds.

Fruiting is regular and abundant.

Enemies of the Hornbeam

The hornbeam is a very sensitive tree to wounds. These wounds are entry points for bacteria and pathogenic fungi responsible for the development of rots.

The thin bark of the hornbeam makes it vulnerable to the "heat strokes" that can be caused by possible burns at its foot.

The qualities of hornbeam

The hornbeam is a tree rather resistant to diseases.

It is a light wood that does not keep well outdoors. Hard and heavy, it is however resistant to shocks. This quality makes it ideal for the manufacture of tool and umbrella handles, billiard sticks and mallets. In the past, it was also used to make most butcher's stalls.

Hornbeam provides a famous firewood that burns slowly, with a bright flame. It also produces a very good charcoal.

Tip

If you want to plant a hornbeam in your garden, do so in the fall. Give it generous waterings in dry, warm weather and mulch the base of new plantings for two to three years with a bed of fibrous compost.

Common chestnut, Castanea sativa : botanical card

Botanical card dedicated to the common chestnut tree, Castanea sativa

The chestnut zone

Native to the Mediterranean basin, the chestnut tree is present in many French regions. However, it remains rare in the north and north-east, although relatively abundant in the northern Vosges.

It was introduced by the Romans in the first century of our era. Until recently, it was mainly cultivated for food purposes, for chestnut flour, and for the wood which was used for multiple purposes.

Portrait of the chestnut tree

The chestnut is a tree that can live more than 500 years. Its growth is vigorous, and it can reach heights between 25 and 30 meters.

Its deciduous foliage forms a fairly dense canopy.

The male and female flowers are distinct, but are borne by the same individual.

Although it is a sun tree, the chestnut tolerates a light shade during its first years.

Chestnut's enemies

The chestnut tree is susceptible to two microscopic fungi:

• ink disease, which can decimate it when grown on inappropriate land;
• the canker; a very contagious parasite, currently in full expansion.

The chestnut tree can also be affected by rust, a detachment of the growth rings which strongly depreciates its wood. This defect, which increases with age, is linked to the growing conditions.

Finally, the chestnut tree is also sensitive to browsing, rubbing and debarking caused by deer.

The qualities of chestnut wood

Chestnut wood is rich in tannins. It is therefore very well preserved, which makes it suitable for specific uses: posts, frameworks, external frames...

Its ability to split is used for the manufacture of cladding.

Its timber is much sought after for furniture (parquet, stairs, furniture), while its very flexible strands are used in basketry and for strapping barrels.

The chestnut tree can also be used as firewood, in closed fireplaces (the wood bursts under the action of heat).

Planting advice

Plant the chestnut tree between November and March.

It can be planted in the sun or under a light shade, and in a non chalky, rather fresh and draining soil.

Growing a wisteria tree

Fabulous, fragrant, graphic, wisteria is generally planted along a façade or used as a climber to decorate arbors and pergolas to which it brings an undeniable charm. As a tree, in the center of a lawn or in the background of a bed, it takes on a whole new dimension. Try it, you won't be disappointed!

The choice of wisteria

If you are adventurous, you can start a wisteria tree from a simple seedling, which will allow you to intervene throughout the plant's growth. However, don't expect to get flowers before ten years or so!

It is therefore preferable to choose a grafted plant, from a garden center or nursery, which will ensure a quicker flowering.

Choose a healthy plant, without any trace of injury or disease, and ask the seller for advice on the variety best suited to your region.

Planting location

Choose a location well sheltered from the wind so that your wisteria does not break. This plant appreciates full sun and a non-calcareous soil. You can add compost, heather soil and humus before planting.

• Dig a 40 cm hole in all directions and plant it with an iron or rot-proof wooden stake of 2.5 m which you will drive at least 60 cm into the ground with a sledgehammer.
• Plant your wisteria at the foot of the stake and fill in the hole.
• Pack the neck of the plant well.
• Water abundantly.
• Hang the wisteria on its stake by making loose cross ties.

The essential pruning gestures to lead the wisteria into a tree

To obtain a beautiful wisteria tree, you just need to prune your plant regularly. Keep only the main stem and cut the small stems and the vegetation starts flush with the main stem. The plant should not branch out. As the plant grows, check that the ties that connect it to the stake are not too tight.

Wait until your main stem reaches a height of about 1.8 m to start keeping three or four stems in its upper part. These will be the carpenter branches. Prune them to 3 eyes, then the secondary shoots they will form, also to 3 eyes.

You will continue to remove all new shoots on the trunk throughout the growth. Do the same on the frames to give a nice shape to your tree.

In a few years you will have a subject that will capture all the eyes!

Tips for planting a tree

The introduction of a new tree in a garden is always an event. It will grow over time, seeing generations succeed one another, unchanging and proud. To succeed in planting a tree, a few basic precautions should be taken to increase the chances of your new protégé's recovery.

The soil: an important criterion

Before choosing a tree, it is imperative to know the various aspects of the soil. First of all, the pH level will determine whether the soil is acidic, calcareous or neutral. You will choose the species according to this criterion rather than modifying the soil, because the results may not be as good as you expect. The nature of the soil also comes into play; a heavy, clayey and humid soil will have to be well drained because few trees enjoy growing in constantly wet soil.

Choosing the variety

Always choose a tree adapted to the climatic conditions of your garden. Avoid tropical species in the North or in the mountains which would have little chance of surviving the first winter. Take inspiration from your direct environment to introduce plants adapted to your region. This way, you will put all the chances on your side and limit the use of phytosanitary products.

Then, it's all a matter of taste: colorful foliage, majestic bearing, sumptuous flowers are all criteria to take into account when choosing your tree.

Anticipating the future

When you buy a tree in a nursery, it is sometimes difficult to imagine its future development. Find out beforehand so that you can plan a location that is large enough for it to develop perfectly. Keep large trees away from the house so that the roots do not cause damage and so that too much shade does not darken your home.

Also consider the regulations and distances to be respected with the neighborhood: trees that will reach a height of more than two meters when mature must be planted at least two meters from the property line.

Planting advice

The planting of a tree should preferably be done in autumn and this, until the month of February, except during periods of heavy frost, when the plant is in its vegetative rest period. This will give the roots time to establish themselves and take advantage of the natural rainfall to grow well the following spring. A spring plantation is also possible for containerized trees, but it will be necessary to water very often during the summer. Choose a tree that is still young, its chances of recovery will be much better.

The planting hole should be prepared about fifteen days before planting.

• To do this, dig a hole twice the size of the root ball in all directions.
• Plant a strong stake facing the prevailing wind.
• Drain the bottom with a bed of gravel or clay balls so that water does not stagnate.
• Prepare your tree by "dressing" its roots, i.e., by cutting off those that are dead or injured and by trimming the tips of the healthy roots to induce the development of new rootlets.
• Then brush them with a praline made of soil, water and cow dung.
• Place a bed of soil at the bottom of the hole and install the tree so that its collar is flush with the soil.
• Top it off with soil to which you have added ground horn.
• Pack the base well and dig a trough with well-decomposed compost at the bottom.
• Water abundantly and fix with specific ties (eight ties) to the stake.