Today in Gardenprue we are going to talk about a very versatile kind of garden. Hornbeam (Carpinus betulus). A tree with a good foliar density that can either be used as a garden tree by letting it grow freely or its growth can be adapted as a hedge. They are rustic, bear pruning well, grow well and are easy to care for.
ORIGIN OF HORNBEAM AND HABITAT
The genus Carpinus currently makes up 42 accepted species of which Carpinus betulus called hornbeam, white hornbeam or birch is one of the most famous. Although its leaves may remind us of a beech tree, in reality it is not since the name of the species (betulus) reveals the name of the Carpinus family, which is the birch family , Betulaceae .
Leaving aside this possible confusion with the leaf, hornbeam is a tree that is not very present in Spain. In fact, it is very unusual to see it in the wild except in the Pyrenean area because from there it is distributed throughout Europe with a spectacular profusion. In addition, in Europe it is usually seen in forests next to oaks, where the beech does not find its place, because as you know, if there is a place, it will inevitably displace oak forests. If you see it in Spain, outside the Pyrenees, please let us know. We just have to look at the GBIF biodiversity map to get an idea. To show a button as they say.
It is native to central Europe and although its presence is centered there, it has been spreading towards the east, already limiting with western Asia.
It is a medium-large tree. It can reach 15-20 meters. When they start to form a crown, it is usually conical, although later, as it grows, it usually ends up rounding and widening up to 10 m. Its growth can be considered fast , up to about 40 cm per year in optimal conditions. Its bark is like that of birch, silver-white and thin, hence it is called birch in addition to hornbeam.
Its leaves are very fine, and it is wonderful to be under a hornbeam forest as they filter the light in a very special way , very similar to beech trees with a very intense green in spring and a beautiful yellow in autumn . As we have mentioned before, the leaves could resemble those of the beech but these have very very marked veins. This tree happens like the oak, which withstand its deciduous leaves on the tree itself until well into winter , some can even stay until spring when it renews all its foliage. We recently told you about the sweetgum with its fiery red foliage in autumn. The combination of the two can be very interesting for a spectacular garden in autumn.
Its fruits are curious for their plant engineering to spread the seed. They have an elongated blade that helps them literally fly when they detach from the tree in order to go further and expand the species. I will always remember the famous “helicopters” of the white maple, when you would fly them and they would flutter like spinning tops. Well, something similar happens to hornbeam in its fruit structure in order to go far. It is a monoecious species with male and female flowers on the tree itself, which are mostly pollinated by the action of the wind.
HORNBEAM AS A TOPIARY ELEMENT IN THE GARDEN OR AS A TREE
It is a tree that supports topiary very well , that is, playing with the shape of the crown to make Versailles figures typical of ornamental gardens in the style of Eduardo scissorhands.
Or we can grow it in a medium-large garden, as a shade tree along with other species. In this case, the Fastigiata (perhaps the most famous) or Columnaris varieties are common, slower in growth but very dense in foliage and with a very attractive pyramidal shape in the crown.
Columnaris is also very suitable for hedges as it is one of the busiest varieties and grows less than the previous one (up to 8 m)
Other varieties are Pendula, Quercifolia or Carpinizza or monumentalis
If you have been convinced by hornbeam, we will tell you about its care and how to plant it in the garden.
HORNBEAM GROWING CONDITIONS
CLIMATE AND EXPOSURE
They are pleasant to direct light and support good solar exposures as long as they do not lack a minimum of water. They endure extreme cold. According to the rusticity classification of the Royal Horticulatural Society of the United Kingdom, it is in the scale of more rusticity, supporting temperatures below -20ºC.
If you want to plant hornbeam as a hedge it is advisable to have a direct exposure since, although it can tolerate the shade, it will not achieve a thickness worthy of a hedge. There will be holes that always give the feeling of a diseased plant, but in this case there will be a lack of light.
It doesn’t need a lot of watering either (considering the central European climate). In Spain if you are going to grow it, depending on the site you should give it water during the harshest summer months . Remember that it is a forest tree although it is quite tolerant to drought . As a recommendation, a padding in the area of the base of the hedge is more than enough to keep the root area moist for longer and space the waterings if necessary.
SOIL AND FERTILIZER
It is not limiting except in heavy, very clayey soils. These are poorly tolerated by root rot but in general it is very tolerant of soils , both in structure and in pH. It supports both slightly basic and acid soils and in terms of texture there are not too many problems, except as we have already said, that the water is retained too much by an excess of clay or for another reason, such as the water table that is very high and continuously soaks the root.
Their root system is not very deep and they tend more to be very dense in the superficial layer.
Once the hornbeam has taken root and its mycorrhizae are stable, it is not very necessary to even fertilize it, although if it is desired in the first years to make it grow faster, mulch, mature compost or fertilizers for green plants can be used.
It is important to bear in mind that this type of forest species such as oak, beech, birch and in this case hornbeam, are species that are very used to the symbiosis of mycorrhizae . In reality, many species need these root fungus associations to be able to get ahead. In the case of hornbeam, it is something important to take into account, and it is very possible that the tree will find it difficult to grow the first years of life precisely because this association is achieved with time.
Before we start propagating, one thing we almost forgot. If you want to form a hedge with hornbeam, you should place about 5 plants per meter , that is, a spacing of approximately 20 cm.
It multiplies by seed, there is no other, it germinates and grows well. It is sown at the beginning of autumn , when the seed is mature but not completely dry. They will sprout in spring. It won’t cost you much and being fast growing, you will be able to assemble your hedge without much effort. If the seed dries then we must scarify it prior to sowing or it will have more difficulties to germinate.
HORNBEAM PRUNING. ESSENTIAL AND INVIGORATING
If it is going to be a hedge it is clear that it supports pruning, and in fact it needs it like any hedge. They are trees that grow with a lot of pull and must be pruned a couple of times a year . One at the end of spring and another during the fall for example with a space of 6 months is fine. It supports severe pruning and trimming well. The sprouts are fast, vigorous and quite dense in general. It is preferable to prune it than not actually do it.
If you leave it as a free tree then you can adjust the pruning a little more to one a year perhaps although nothing will happen to it by pruning it twice.
The pruning of the hedges is the easiest and most rewarding. Do not be thinking, which branch do I leave and which one do I cut? Above how many shoots? And if I cut this branch, will it decompensate? What if I prune too much? These are the typical questions that arise when you start to put the pruning shears to any plant. In these cases, go cutting and making the shape that you like best.
DO YOU REMEMBER THAT LEAVES COULD BE COMPOSTED?
Years ago, I say well, years that we have told you the possibility of including in your compost pile for the garden and the garden the litter of the deciduous trees . Hornbeam leaf is ideal because being so thin it decomposes very quickly and we accelerate the formation of compost and it supposes very neutral and rich matter for our compost pile.