Honeysuckle

Family Caprifoliaceae. About 180 species are known in almost all regions of the Northern Hemisphere, mostly from the Himalayas and East Asia.

The flowers are fairly large (white, pinkish, yellowish and blue), usually arranged in pairs in the leaf axils or at the ends of branches in capitate inflorescences. From a weakly developed calyx emerges an irregular (in most species) tubular corolla divided at the end into 5 lobes; the zygomorphy of the five-part flowers is due to the fusion of three anterior petals and their unequal development, so the corolla is two-lipped; in the corolla tube there are 5 stamens and a long style of the pistil.

Berry-like fruits are borne in pairs and often fused together. The upper leaves of some species (and in others all the leaves) are fused together, forming a single common blade or a broad rim through which the tip of the flowering shoot passes.

Honeysuckles are undemanding, winter-hardy; their flowers are delicate and their fruits decorative; in some species the fruits are edible.

In nature, honeysuckle species are distributed unevenly. Most species are concentrated in Southeast Asia, which apparently is the native region of this genus. Overall, honeysuckles grow mainly in the Northern Hemisphere, occupying vast temperate areas in North America, Europe and Asia, reaching into the subtropics and tropics only in Southeast Asia.

Honeysuckle species can be found in coniferous, deciduous and mixed forests of temperate climates, in shrub thickets of desert zones, and at the upper limits of tree vegetation in mountains. Adapting to different conditions, the plants may have various growth forms and different requirements for light, moisture and soil. In the tropics and subtropics evergreen species occur, which are not suited to the harsh winters of the temperate zone. Therefore our attention is focused on deciduous species, the diversity of which is also large: among them are tall shrubs that could be regarded as small trees because of their size and fairly thick stems, low prostrate and creeping shrubs, and highly climbing lianas. Unfortunately, only a small part of the decorative honeysuckles are used in modern gardens and parks. Besides widely known plants such as caprifol and Tatarian honeysuckle, there are many diverse and hardy species worthy of attention.

The root system of these plants lies close to the soil surface. Leaves in honeysuckles are always opposite (arranged in pairs opposite each other). They are usually uniform in shape, more often entire-margined, less often wavy-edged, oval or elliptic. Leaf apices may be rounded or pointed, less often acuminate. Flowers are nectariferous and often fragrant. Among honeysuckles there are species with white, cream, yellow, pink and crimson flowers, usually paired in the leaf axils. All the corolla petals are fused, forming an elongated tube and a 5-lobed limb. The calyx is generally poorly developed.

Flowers of climbing species are collected in capitate inflorescences, most often sessile. Inflorescences are surrounded by round or oval discs formed by the fusion of leaves.

Fruits may be red, orange, black or blue. These are juicy berries with small seeds. Pairs of berries frequently fuse completely or partially, forming an aggregate fruit on whose apex the attachment points of the two corollas are clearly visible.

In edible varieties the dark-blue aggregate fruits are variable in shape. The apex of the fruit is the most variable: it can be pointed, strongly elongated into a beak, or flat as if truncated, with a saucer-like rim.

Among honeysuckles there are many well-known ornamental and comparatively undemanding shrubs. Tatarian honeysuckle is often used in landscaping of parks and squares; Korolkova honeysuckle also blooms lavishly and abundantly. Honeysuckles are good sources of nectar and their flowers are aromatic. These plants are attractive during fruiting as well, although many of their fruits are inedible. In most decorative species the fruits are red, but there are orange and even black ones.

Location: they flower and grow best in sunny places and in partial shade. In deep shade they flower poorly. Most honeysuckles, especially the climbing species, are light-loving and prefer open sunny sites. However, forest species can tolerate some shade and will grow well in a garden under the canopy of trees. Under such conditions higher air humidity is maintained, which is particularly important for these plants.

Soil: honeysuckle grows well on any soil but develops best on loose, well-drained soils. Very dry sites and enclosed hollows are unsuitable for planting.

Potting mix consists of turf soil, humus or peat and sand in proportions 3:1:1. Optimal soil pH is 7.5–8.5. On heavy wet soils as well as poor sandy soils honeysuckles grow poorly. Drainage of broken brick or gravel 5–7 cm thick is required.

Planting: tolerates transplanting well. When planting in a permanent place in the garden maintain a spacing of 1.5–2 m between plants. Spread the roots carefully and cover with soil. Then water abundantly and mulch. The root collar should be at ground level. In an amateur garden it is convenient to place bushes as a hedge along the edge of the plot. For creating decorative groups increase the spacing to 2.5–3 m.

Plantations are established with 2–3-year-old seedlings. For such bushes prepare a planting hole 25–30 cm deep and 25 cm in diameter; for 5–7-year-old bushes the depth and diameter should be 50 cm.

Spring planting is suitable for species with late vegetation—alpine, creeping, Maack, Tangut, small-leaved, etc.—and is less desirable for blue honeysuckle: its vegetation starts very early (at the end of April), when the soil has not yet thawed, and by the time planting can be carried out it is already in bloom. If young plants can be planted with good care, adult plants may lose flowers, which will affect survival and fruiting of the bushes.

The most favorable time for planting blue honeysuckle is from August to mid-October. Plants do not suffer from autumn planting. Firstly, they are highly winter-hardy, and secondly, by mid-summer the growth of shoots ceases and terminal buds are set.

Plants with a closed root system can be planted from spring to autumn.

Since honeysuckle is a cross-pollinated plant and a single bush will not pollinate itself, it is necessary to plant at least 3–5 different varieties on one plot.

Care: honeysuckle, like any plant, responds well to attentive care. The better the growing conditions, the more abundantly the bushes bloom and the more fruit can be harvested from edible varieties.

Early in spring apply a complete mineral fertilizer at a rate of 20–30 g/m2; before flowering give liquid feedings with Kemira-Universal at 20 g per 10 L of water. With weak growth of young plants foliar feeds are practiced: 0.1% urea, 1% superphosphate, 0.5% potassium chloride. Summer watering by sprinkling is also very beneficial. In autumn apply wood ash 100–200 g/m2 when digging. If fertilizer was applied at planting in the amounts: 5–7 kg of manure, 50–80 g of superphosphate and 40–50 g of potassium salt per planting hole, no additional fertilizers are needed for the next two years.

Water honeysuckles moderately, 2–3 times per season, in hot and dry weather 8–10 L per plant. When grown without irrigation, especially on heavy clay soils, bitterness in the fruits becomes more pronounced even in edible dessert varieties 'Gerda', 'Zolushka', 'Kamchadalka', 'Moskovskaya 23', 'Sinyaya Ptitsa', and yield may decrease while fruit drop may increase.

When the soil is compacted and weeds are removed, loosen the soil to a spade's depth (20–25 cm). Mulch not only the root circles after planting but also in autumn spread peat around the plants in a 3–5 cm layer. This serves as both protection and nourishment.

The most suitable time for pruning honeysuckle is autumn (after leaf fall) or early spring (in March). Every 2–3 years rejuvenate and thin aging bushes by cutting out small and old branches, leaving no more than 5 vigorous stems. With gradual removal of the central part of the crown with aging branches, new suckering shoots begin to form.

Bushes older than 6–7 years require sanitary pruning—removal of diseased, broken and dried branches. First to be pruned are dry shoots and branches of the lower shaded tier that lie on the ground, hinder care of the shrub and do not participate in fruiting.

It is not recommended to cut off the tips of shoots of blue honeysuckle, since they contain the greatest number of buds with flower primordia, and damaging them reduces yield.

For old 15–20-year-old bushes a strong rejuvenating cut "to a stump" is possible, performed at a height of 0.5 m from the soil surface. Due to young suckering shoots the shrub can recover within 2–3 years.

Winter preparation: no special winter protection is required. Only occasionally the shoot tips are slightly damaged by frost, which does not reduce the decorative appearance of the plants.

Propagation: easily propagated by seeds and green cuttings, by layering, and they produce suckers from the stump.

Green cuttings are considered the most effective method of propagating honeysuckle. The time for cutting green cuttings of blue honeysuckle coincides with the appearance of green fruits. Shoots are ready for cutting when they break with a characteristic crunch rather than bending.

If cuttings of blue honeysuckle are taken during active growth before the appearance of green fruits, rooting will be less than 45–60% because at that time shoots have not ripened and will rot during rooting due to high humidity.

If cutting is postponed until late July, when shoots have already lignified, rooting will be better, but the cuttings will not have time to prepare for winter.

Cutting of cuttings. Cut cuttings in the morning before strong heat or in cool weather. First cut vigorous green shoots of the current year on the bush. Green cuttings are taken from the middle part of the shoot, preferably with two nodes (two pairs of leaves) and one internode. Optimal cutting length is 7–12 cm, diameter 0.4–0.5 cm. If the shoot has short internodes, take a cutting with three nodes.

The upper cut of the cutting is straight, 1–1.5 cm above the bud, and the lower cut is usually slanted (45°). Leaf blades from the lower nodes are removed completely, and from the upper nodes trimmed by more than half.

Cuttings with a "heel" that are obtained by breaking off the lower part of the shoot from the previous year's twig root well. Shortened shoots are prepared this way. Shoot tips also root well.

Planting cuttings. Cut green cuttings must be planted immediately. For rooting cuttings a substrate consisting of peat and sand in a 1:3 ratio is required. Cuttings are planted at an angle of 45°, spaced in a 10x5 or 7x5 scheme.

A necessary condition for successful cutting propagation is high humidity of the substrate and air (up to 85%) at a temperature of 20–25°C. Such conditions are maintained in a plastic film seedbed or glazed greenhouse with regular watering and frequent spraying, especially in hot weather.

Under optimal conditions roots appear already on the 8th–10th day after planting. From this time cuttings begin to be hardened by opening doors and vents for 20–40 minutes. At the same time increase the duration of sprayings and intervals between them.

It is not recommended to transplant cuttings outdoors in autumn. During snow melt the soil swells and cuttings with weak root systems may be "pushed out" to the soil surface, their roots exposed and they may die.

It is more reliable to leave the cuttings in a film greenhouse and, after the film is removed, cover them with spruce branches until spring. Spring aftergrowth gives good results for vigorous varieties of honeysuckle.

Rooted cuttings are planted in a permanent place in the second year. In the third year some plants already begin to flower and fruit individually.

Green (summer) cuttings easily propagate blue, golden, black, common, Tatarian, Tangut, Ruprecht, Korolkova and Schamisso honeysuckles. Summer cuttings of alpine, Maack and small-leaved honeysuckle root with difficulty.

Propagation by hardwood cuttings is recommended for Morrow's honeysuckle. Cuttings are wrapped in damp burlap or thick paper and stored until spring in a cool place in boxes with sand or sawdust.

In spring the lower part of the bushes is heaped with soil to a height of 10–20 cm. During the summer and in dry periods watering and earthing up are required. The following spring the soil mound is dug out and the required number of rooted shoots separated and transplanted.

Division of the bush is best done on 3–5-year-old plants with a loose crown, especially those planted with an 8–10 cm deepening. Mature bushes whose shoots branch above ground level cannot be propagated this way. In early spring or autumn during leaf fall an overgrown bush is dug up and carefully divided with a saw or secateurs into 2–3 parts with the root system, then the divisions are planted in a new place.

If hardwood cuttings of blue honeysuckle are taken after leaf fall (in late September or early October), then with spring planting only 10–15% will take.

Honeysuckle is propagated by seed for breeding purposes and in amateur gardening. Seed propagation does not preserve the traits and qualities of the parent plant, so one cannot predict yield and fruit taste. Bushes of edible honeysuckle grown from seed may have more bitter fruits than their cultivar parents.

Seeds are extracted from the largest and ripest fruits. To do this, fruits are pressed in a gauze or nylon bag. Then the seeds are placed in a container with water where they sink to the bottom while floating bits of pulp are removed. Fruits can be rubbed through a sieve and then thoroughly washed. It is faster and easier to crush the fruits on thin blotting paper absorbing the juice. After drying this sheet with seeds can be rolled up and stored at room temperature until sowing time.

Seeds of early-ripening honeysuckle species can be sown in summer immediately after collection (in July) into the ground or into wooden containers covered with film to retain moisture. After seedlings appear remove the film. By autumn the seedlings will form 3–4 pairs of leaves and grow somewhat.

To protect delicate seedlings that overwinter under snow, cover them with spruce branches. In autumn (late October) seeds of Korolkova honeysuckle can be sown. By overwintering in dormancy under snow they undergo natural stratification and germinate well in spring. By mid-July they can be pricked out. By the end of the season seedlings reach 10 cm or more in height.

The best and most reliable sowing is in spring in March–April. A day before sowing seeds should be soaked in a weak solution of potassium permanganate (light pink). Because of their small size seeds are better sown not directly in the ground but in wooden boxes or flower pots. Prepare a light fertile soil consisting of equal parts humus, peat and river sand. Seeds are spread on the soil surface and pressed in, then covered with a 1 cm layer of sand. The container is covered with glass or transparent film.

For successful germination indoors maintain a temperature of 20–24°C and regularly moisten the soil. Watering is done carefully, adjusting the stream so as not to wash out surface seeds. If this happens, seeds should be gently re-covered with soil.

Honeysuckle seedlings appear in 30–35 days. In the second year (in May) seedlings are pricked out into beds at 5 cm spacing and watered carefully. In the first days after planting seedlings must be shaded.