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Breeding methods for conifers

Wanting to create a "prickly collection", or wanting to grow plants of the variety you need, many gardeners prefer not to buy the trees they like, but to cultivate them themselves. Reproduction of coniferous plants is a painstaking and very exciting process. Most often resort to cuttings, growing from seed or grafting method is no less popular.

Conifers - an ancient and diverse group of plants that can reproduce with great efficiency. Conifers do not have flowers and inflorescences, no pistils and stamens, their genitals are called strobila. Male strobiles carry pollen and are called microstrobiles, female ones form fruits after pollination and are called megastrobiles. Of course, it would be more familiar to talk about pollen spikelets and cones and call it flowering, but, from a botanical point of view, this is a mistake, since not all conifers have such formations. And yet, for simplicity, we will sometimes use the term "bloom", hiding it in quotes.

On this page you will learn how coniferous plants breed, and how they grow from seedas well as in other ways.

How do conifers breed?

As for the “sexual orientation” of conifers, that is, among them there are both dioecious plants and monoecious plants, in which both female and male “flowers” ​​are formed on the same plant. Male "flowers" (microstrobes) are small in most conifers and sometimes are collected in "inflorescences". Women are almost always gathered in "inflorescences".

Coniferous forests are pollinated by the wind and that is why they have very light pollen that is spread over long distances.

Most often fertilization occurs between specimens of one species. Hybrids as a result of pollination of various forms occur very rarely. Fertilization is not possible between representatives of different families, it is possible between different genera in the same family, but not found in nature, between different species of the same genus occurs, but very rarely due to the natural isolation of the populations.

Seeds are collected either in cone-cones, or hidden in fruits similar to berries or nuts. The size and shape of the seeds of conifers of different families, genera and species differ significantly, but most often they resemble nuts. The rind of the seed is always leathery or woody. The seeds of some species have wings, which allows them to spread with the help of the wind, others have lush covers and are spread by animals, mostly birds. So conifers breed in natural conditions.

For the propagation of conifers in horticultural crops, it is extremely important to use methods that make it possible to completely repeat the signs of maternal forms. The problem is that only natural, “wild” species are capable of identical reproduction by seeds, and their varietal forms give significant “splitting” during seed reproduction. During vegetative reproduction of homochnikov, the characteristic features of the breeds are preserved, although this does not always repeat the typical form of the crown.

We will try to help you in choosing the most simple and effective methods of breeding conifers and suggest the most rational way for the conditions of your garden.

To get started, learn how to propagate conifers with seeds.

How to grow coniferous trees from seed: scarification

The seed propagation method of conifers can guarantee the identity of only natural species, but the cultural forms for the most part are not repeated.

The seeds of conifers contain a large amount of oils and quickly lose their germination. Seeds with dense, undisturbed covers can be kept warm for up to 2-4 years, and in an airtight container at temperatures close to 0ᵒ С more than 15 years. Significant fluctuations in temperature and humidity during storage lead to a reduction in this period. Seeds with poorly formed or damaged covers are not suitable for storage and require immediate germination.

For the cultivation of conifers from seeds, it is necessary to master the basic agrotechnical techniques developed for their more effective germination in scarification, stratification and snowing.

Scarification means a violation of the dense and impenetrable covers of the seed, preventing its swelling and germination. Under natural conditions, this process is carried out due to the work of soil microorganisms and the treatment of seeds with enzymes during the digestion of food by animals.

For the vast majority of the seeds of conifers, scarification is not necessary, but this procedure always ensures more germinating germination. The only “northern” conifers for which the scarification of seeds is necessary are junipers и yew. Fruits are washed from succulent covers, dried, and then placed on 30 minutes in concentrated sulfuric acid. After such a "brutal" operation, the seeds are carefully washed in running water, sown or stratified. A simpler, but less effective method of scarifying dense covers is to shake the seeds in a jar lined with coarse sandpaper from the inside. Violation of seed covers is carried out immediately before sowing - such seeds are unsuitable for storage.

Stratification of seeds before growing conifers

Stratification is a method used for seeds with delayed embryo development, the germination of which requires a long (sometimes up to 2 years) period of time with even temperature and humidity. The seeds of many conifers are vital stratification.

Stratification is cold, warm or combination, and the choice depends solely on the origin of the plants. Seeds of southern species need warm stratification, northern - in cold. Seeds of temperate plants ripening in mid-summer require a combined stratification: first warm and then cold. The temperature at which the process takes place is the only fundamental difference between the methods.

Conditions for the efficient passage of stratification are even temperatures, moisture absorption by seeds, good aeration of the substrate and the duration of the process (usually from 1 to 6 months). Only when these conditions are met, changes occur in the seed that prepare germination.

The term stratification literally means “sandwiching,” and the main method of this technique is indeed alternating sandwiching of the germinated seeds with sphagnum moss, sawdust or clean coarse sand. This technique is good only for large (industrial) batches of seeds.

For stratification of small lots of seeds at home, the following method is recommended:

  • Seeds are scarified if necessary.
  • Then mixed with a wet substrate in a ratio of not less than 1: 3. Best substrate - it is pure coarse sand or a mixture of sand with peat or spun moss with peat moss. Stratification is also possible in pure conifer sawdust.
  • Seeds are placed in boxes, boxes or plastic bags.
  • Small batches of seeds should be sown directly in pots and stratified into them before germination. The earth mixture for sowing should be clean, light and consist of rotted leaf earth, peat and coarse sifted sand in the ratio 3: 1: 1.
  • Knotted bags, closed boxes or pots of crops stored in a dark room with a temperature corresponding to the type of stratification. With warm stratification, it is + 15-22 ᵒС; during cold stratification it is from 0 to 10 С depending on the type of plant (in this case, the crops are placed in a refrigerator or cellar).
  • During the entire period up to germination, the seeds must be viewed from time to time, mixed, and during long-term stratification, the substrate is changed and the seeds are washed.

Care should be taken to maintain moderate substrate moisture: Drying suspends the process of “ripening” the embryo and can cause “secondary rest,” from which it is difficult to remove seeds. Excessive moistening of the substrate is even more dangerous, since it leads to seed rotting.

  • After the stratification is completed, seeds are removed from the substrate and sown according to the requirements of the species, either in pots and boxes in protected ground or directly on the street ridges. Crops stratified in pots are exposed to the light. The seeds of most species of conifers are able to germinate even in the dark - such shoots accustom to the light gradually.

Some gardeners before the propagation of hvoyniki, resort to the method of snowing. This is not always an effective, but very simple method designed for germinating seeds that do not require either a long cold or warm germination period: larches , ate , pines , fir , tsugi , pseudo , thuya etc. The essence of it is that the seeds are sown in wooden boxes and put up for the winter under the snow. In the spring, crops are transferred to moderately warm greenhouses or driven into the ground until germination.

Next, you will learn how to propagate conifers by growing seedlings.

Growing seedlings of conifers

Seedlings of conifers are hardy and quite unpretentious. The main requirements for the successful development of young plants are well-rotten loose moderate moist soil and sufficient diffused lighting. Prolonged exposure to direct sunlight can cause burns on seedlings. Fresh animal organic matter in the soil, excessively high humidity of the substrate and hot air inevitably lead to the development of parasitic fungi and the death of seedlings.

Seedlings can be grown both indoors and outdoors. With both options, there are both pluses and minuses. When the seedlings are kept in pots, bowls or boxes, it is difficult to maintain the balance of soil moisture; on the ridges, seedlings cannot be isolated from climatic disturbances.

During the first year, the seedlings develop rather slowly, as it builds up the root system, and from the second year it is actively starting to grow. Young seedlings easily tolerate transplantation and are not afraid of pruning the roots, moreover, planting tight plantings is extremely necessary, this ensures the correct formation of the crown and ensures the creation of a compact root ball. Transplantation is possible during the whole summer season, but is not desirable in hot, dry weather and during a period of active growth.

For the intensive development of seedlings of most species of conifers, loose loamy or nutritious sandy loam soil is required. You can make additional food, but only during the growth of shoots (active growth). Extremely dangerous feeding with fresh animal organic matter, leading to burns of the roots, and often to the death of plants. The most acceptable organic fertilizer is completely fermented clarified slurry. But it is more reasonable to feed with low concentration mineral fertilizer solutions. According to the author’s experience conifer seedlings does not require additional dressing at all and is completely content with adding fresh fertile land.

Vegetative reproduction of conifers

Vegetative reproduction of plants is the rooting of shoots separated from it. Most of the methods of vegetative propagation of conifers ensures the repetition of characteristic species or varietal traits. During the reproduction of plants with a vertical crown, the preservation of this trait is possible only in the case of the choice of directly growing, but not bent, shoots. The same problem arises during reproduction with vaccines - “regular” specimens are formed exclusively in ampelous, cluster and spherical varieties, and in vertically growing crown it develops unevenly.

The vegetative reproduction of each individual species, and sometimes even the varieties of conifers, are individually adapted, following, however, common, long-established techniques.

Reproduction of coniferous trees by dividing

Propagation of coniferous trees by dividing is rarely used, but it is appropriate for private gardens and small farms. It is suitable only for multi-stemmed, as a rule, varietal tight-custard forms, especially for members of the cypress and yew-tree families.

Coniferous bushes are divided in cool, humid weather and at the same time that transplantation of this species is recommended. Naturally, young plants tolerate division less painful than old ones.

The division is most effective after preliminary deepening or hilling of the lower branches, i.e. rooting of vertical cuttings.

Horizontal Lines

This method of vegetative propagation is unproductive and suitable only for private gardens. The method is absolutely harmless to the mother plant, but, unfortunately, is only good for species with flexible branches and an indefinite or horizontal crown shape. In most cases, crooked or creeping specimens grow from rooted branches.

The reproduction technology of the western thuja division by the bush is simple: in spring or early summer, the branch is bent to the ground and slightly instilled, raising the top, and then fix the place of the bend with wire or weight. For better rooting, it is advisable to carefully tear off or cut off at the base of all the small branches that have fallen into the ground, and under large branches make light cuts of the bark to wood or constriction with soft wire. During the rooting period, it is necessary to maintain even soil moisture. Rooting occurs during the year, sometimes more, and you should not rush into separating the branch from the parent plant - it is advisable to carry it out in stages, gradually cutting the junction, thereby transferring the branch to its own roots.

The next section of the article is devoted to how to propagate coniferous plants by cuttings.

Reproduction of coniferous plants by cutting

Reproduction of coniferous plants by cuttings is the most productive, but also the most difficult method, based on rooting of shoots separated from the mother plant. The cuttings of conifers are the only method that guarantees the complete repetition of all varietal characteristics, but only if the cutting is correctly selected.

When choosing a cutting and calculating the percentage of rooting, it is necessary to remember some immutable truths:

  • The ease and specificity of rooting cuttings depends solely on the species and species. For example, cuttings cypress treestui TUEVIKOVjuniper microbiota and yew rooted quite easily. Somewhat harder to succeed with cuttings Metasequoises, hemlock and varietal spruce, fir and pseudo. Rooting cuttings of pines and larches is practically impossible.
  • Easier than the rest rooted cuttings from young varietal plants, especially this applies to plants with small soft styloid or needle-shaped needles.
  • Quite easily rooted cuttings varieties with compact densely branched crown.
  • Cuttings taken from indoor (greenhouse) plants rooted much better than similar shoots of “street” specimens.
  • Weak, thin and lateral shoots take root much faster than strong and vertically growing.
  • Poor rooting cuttings taken from strong overfed specimens.
  • Cuttings from plants of natural species, especially from old specimens, root very badly.

Before propagating coniferous plants with cuttings, you need to prepare a special, well-drained ridge. A frame covered with a film is installed on it (tunnel-type greenhouse). Trees can be grown in a greenhouse with high humidity and temperature, adjustable from + 15 to 25 ° C. Contain cuttings directly in the ground or in shallow boxes filled with loose, well-aerated substrate.

The best substrate for grafting coniferous plants is coarse washed sand.

Excellent additions to sand are perlite in the ratio of 1: 1 or 2: 1 and high sour peat (3: 1). Good mixes are obtained by adding vermiculite to the sand, chopped sphagnum moss and crushed sifted coniferous bark. The substrate layer in which the cut cuttings are fixed should be small (approximately 5-10 cm), but not less than the depth of their embedment. In boxes designed for grafting, it is necessary to ensure good drainage, for which gaps covered with slats, rubble and sand are obligatory at the bottom. Cuttings in small dishes (pots and bowls) are usually unproductive because of the difficulty of maintaining an even humidity and temperature.

The best period for grafting is spring before or at the beginning of the awakening of the kidneys. It is possible to conduct cuttings of conifers in the summer, after the end of the first wave of growth and hardening of young shoots, but in this case, the cuttings do not always have time to form roots and hibernate only with the influx of wound tissue (callus), which makes their maintenance difficult. When breeding coniferous room reproduction, cuttings are shifted in accordance with the stage of plant development.

The optimum temperature for rooting is from + 20 to 23 ° С. Moreover, during spring cutting in the initial period, it is necessary to maintain a lower temperature (+ 1 ... + 18ᵒ C) until the bud starts to bloom and only then raise it to + 20 ... + 23 С. Temperatures above + 25 C are undesirable. For more effective rooting, lower heating can be recommended when the temperature of the substrate or soil on which the boxes stand rises by 1 - the maximum 2 degree is above the air temperature. The most appropriate bottom heating when rooting spring cuttings.

Direct exposure to cuttings that cause overheating is dangerous. That is why the ridges or boxes with cuttings must be pritenyat lutrasil (spanbond), gauze and paper, including newsprint.

Optimum humidity of air at rooting of shanks - 95-100%. Ideal is the constant presence of fine water dust in the air - this is why it is advisable to root conifer cuttings in special greenhouses with fogging installations.

Particular attention should be paid to the moisture content of the substrate - it should never be excessive. Excess moisture leads to the death of the cuttings, which must constantly receive oxygen not only from the air, but also from the soil. Even the temporary drying of the substrate is not as harmful as its waterlogging. To maintain moderate and even soil moisture, greenhouse and greenhouse ridges, as well as cutting boxes, should be well drained.

Cutting of conifers in spring and summer

The choice of cuttings from cultural forms is extremely important. In columnar and narrow pyramidal varieties take only straight, seeking up, but not the most powerful shoots. In creeping varieties cut any, except vertical, cuttings. For plants with a free, oval or spherical crown, the choice of a cutting is not essential.

With spring breeding, the shoots take the shoots of last year's growth, for the summer - the ripe shoots of the current year.

Shoots for cutting cuttings harvested in the morning or in cloudy weather. If they are not planted immediately, they wrap them up with a damp cloth and keep them in the fridge without drying. Long storage at constant humidity is possible, but undesirable.

Before cutting in the lower part of the cutting, without injuring the bark, remove the needles. This is necessary to prevent its rotting during the rooting period. Small needles can be left.

The size of the cuttings may be different depending on the strength of the growth of the multiplied specimen. In practice, cuttings of vigorous forms are larger than dwarf ones.

It is useful for the cuttings to have a “heel” - a small piece of bark with wood from the previous growth. That is why the best cuttings are short side branches, torn from the main branch with a piece of old wood. If the “heel” is too long or split, then it is carefully trimmed. If a lot of material is harvested at once, then, as soon as the cutting is cut, it is thrown into water or wrapped in a damp cloth. Long keep cuttings in the water is unacceptable.

The use of stimulants gives good results in cutting the coniferous plants, but only with perfect adherence to the instructions attached to the preparations.

Chopped cuttings are fixed in the substrate. To do this, a stick slightly thicker than a pencil at an angle 60-70 degrees make a hole into which the cutting is inserted, and firmly press it with the same stick to the substrate. It is very important to preserve the previous orientation of the cuttings - they cannot be turned over with the back side of the branches up.

Spring and early summer cuttings can take root by the middle of summer, summer - only by the end of autumn. There are frequent cases when by the autumn the cuttings do not form roots, but have a thickening in place of the cut - wound tissue callus.

The greatest danger in rooting is a combination of sudden changes in temperature, high humidity of the substrate and dry air, leading to the death of the cuttings.

The key to success in reproduction of branches is by cuttings of air: high air humidity, moderate humidity of a clean, friable substrate, even room temperature, and sufficient, but diffused light.

Well-rooted plants of northern conifers overwinter without shelter. Weakly rooted or live unrooted cuttings can overwinter with air-dry shelter. A box or wire frame is placed above them, covering the top with coniferous spruce branches. In the thaw, they must be ventilated, and in the cold, additionally covered with plastic and cloth. Cuttings rooted in boxes are either kept in bright, cold greenhouses until spring, or they are instilled into the ground together with the boxes and warmed with an air-dry shelter. The cuttings of the “southern” conifers overwinter in bright cool frost-free rooms.

Propagation of coniferous trees

Many species and varieties of conifers is almost impossible to propagate either by seed, or layering, or cuttings. The only way out - vaccinations. They are used for different purposes: to speed up the fruiting (cedar pine), to obtain original forms (balls and cascades on shtamba), for the accelerated reproduction of rare varieties. Methods of grafting conifers and deciduous plants are the same. Especially popular are copulation, grafting in the lateral cleft, and behind the bark. To create standard specimens traditionally used the method of vaccination in the side split.

However, as a result of years of research, a method has been developed that is specialized specifically for conifers. The developer of this method of vaccination, called the “core-to-cambium core”, is the agronomist-practitioner E. P. Prokazin. The best period for vaccinations using this method is spring, early summer (before the growth of the kidneys).

They are carried out in open ground or in cold greenhouses. Weather conditions during the accretion period are not significant, but moderately warm dry weather is preferable.

This method of grafting is suitable for plants of all conifers. The author investigated the 45 variants of interspecific and intergeneric vaccination combinations.

On pine ordinary were vaccinated and grown together: 12 pine species, 11 fir species, 8 species fir, Menzies pseudo and Siberian larch.

On ordinary spruce: 3 species of spruce, 3 species of fir and larch.

On Siberian larch - 2 species of pine and spruce. But at the same time, one should know that after several years, these interspecific inoculations of conifers can cause the death of the scion, its rejection.

Particularly developed is the grafting method “core-to-cambium core” for pines. The cuttings are taken as shoots of adult healthy trees, formed by two-three-year increments of length 8-10.

All the needles, with the exception of 8-10 bundles near apical buds, are cut off without damaging the bark, and the lateral branches are cut off. After that, the cutting is cut along, through the core, so that the cut begins immediately under the needles, digs sharply, passes through the middle of the core and disappears at the very bottom of the cutting, forming a small one-sided wedge. A cut length of 5-6 cm provides a complete accretion.

The rootstocks are 4-5-summer pines in forest plantings. Preparation of the rootstock for grafting is reduced to trimming the ends of the side branches, removing the lateral buds of the axial shoot and needles in the upper part of the axial shoot on 3-4 cm below the apical buds.

On the part of the rootstock which is released from the needles, which should slightly exceed the length of the graft, impart a strip of bark that is equal in length and width to the cut on the cutting. The cut should be made exactly along the cambial layer so that the wood is not damaged, and at the same time a layer of bast fibers is not separated on the surface of the cambium.

The stalk laid on the cambium is tightly pressed first with rare and then more frequent (through 1,5-2 mm) windings. For this purpose, often use thin rubber strips or threads for darning. Tying should cover the entire cutting to the needles. When conducting vaccinations in open ground is desirable, but not required, plastering garden pitch. If the vaccination is done in late spring - early summer, then the strap is removed after 4-5 weeks.

Subsequently, cut off the ends of the branches of the first whorl and axial escape of the stock above the site of inoculation. The preservation of the side branches of the stock depends on the growth of the grafts. With normally growing grafts, the rootstock branches can remain for 2-4 years, and for poorly developed grafts, this period can be doubled. In some super-miniature varieties (they are sometimes called micro-varieties), the rootstock branches remain throughout life, contributing to their normal life activity.

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