Botanical and habitat notes
Over 600 species belong to the botanical class of conifers, mainly spread in the temperate-cold climate zone, and with less diffusion, in the tropical.
In these areas the spontaneous conifers grow at variable altitudes: from the maritime area up to the maximum limit allowed for vegetation.
Their adaptation to the environment is to be considered typically specific, since they distinguish species of temperate and warm climates such as the maritime pine and the cedar of Lebanon, and other mountains suitable for the cold such as mountain pine or fir trees of Canada.
All conifers in general they can be defined as rustic or frugal towards the soil, because thanks to their great radical efficiency they can develop even on rocky cliffs, while, probably due to this particular specialization, they do not bear heavy and very humid soils.
The main botanical character that distinguishes them is given mainly by the type of leaves, which are needle-like and persistent (not deciduous) for most plants.
The prevailing vegetative form is the conical one, this character is not however distinctive, since many species are known with umbrella-shaped habit (Pinus) or prostrate up to be even creeping (Juniperus).
Another character present in this class is the abundance of aromatic essences and resins, which are normally produced by the plant in canals, known as resinifers, and which serve the same for the protection of wood.
The longevity of conifers and the size they can reach is perhaps exclusive among all the plants: for example, the Sequoia can easily reach 100 m in height, with a diameter of over 12 m and it is estimated that some are at least 1,500 years old.
The flower they produce is generally cone-shaped (botanically called strobilo), a characteristic that probably originates the name of the class.
At maturity numerous seeds are formed which in some cases are used for feeding, such as in pine from pine nuts, or for the extraction of oils, but in other cases (Taxus) they can be toxic to poisonous.
And conifers as ornamental plants
They are to be considered as ideal plants for various reasons, including the persistence of the foliage and their bearing, the coloring of the needles and not least, the fragrance due to the resinous essences.
Very common is the use as a hedge in the genus Thuja, thanks to their marked pruning tolerance.
Conifers in the garden project
For the various reasons of adaptability in the creation of the garden, one of the main warnings is that of choosing the "right" species for the "right" environment, considering also the dimensions that some of these require as living space and consequently the distance from other plants and buildings.
It is good to also evaluate the type of soil on which you intend to cultivate them and it would be better to have it analyzed, precisely because both the physical point (STRUCTURE) and the chemical point (REACTION or pH) can lead to the main causes of failure.
Pruning of conifers
Free-bred species require few but targeted pruning interventions, especially aimed at eliminating double buds or rearranging them accidentally damaged and also for the elimination of broken or too low branches, which can be easily ruined due to the frequent passage with tools different.
Sometimes the pruning is done outside the optimal period (autumn - winter), such as for example the elimination of "processionary nests" insects that develop in the spring period or for the elimination of branches that show pathologies such as the cancers.
On pruning cuts or on wounds it is good to intervene in any case with a cicatrising agent in order to protect the wound from pathogen penetration.
Fertilization on this type of plants is wrongly considered not essential, however in situations different from their natural HABITAT they take undoubted advantages especially if the soils are alkaline and tenacious or if used in hedges and therefore subjected to frequent cuts.
Referring to what was said for the warnings to the plant, these essences are periodically fertilized with granular products.
This advice is also particularly suitable for Thuja hedges or Leylandi cypresses, in order to reinvigorate and thicken the foliage.
To cure and prevent the yellowing of buds and foliage, typical of heavy, calcareous or iron-deficient soils, specific anti-chlorosis products must be distributed.
Garden conifers: Adversity and care
Various adverse causes are affecting conifers especially if cultivated in difficult soils or in critical growth stages as in post-transplantation.
It is precisely defined as "environmental" for example the type of soil is not ideal, pollution, these causes that can lead the plant to a general debilitation and a predisposition to "parasitic" attacks for the loss of self-defense resources.
Among the parasitic causes there are those of origin:
· Vegetable or mushrooms
Cortical and rameal cancers
Basal or collar rot
Armillary root rot
Animals or insects
Bark beetles or wood destroyers
Lepidopteran larvae and processionary moth
All these adversities can be prevented and / or treated with specific plant protection products.