"White acacia clusters of fragrant ..."
The genus is named after Vespasian Robin, who first brought this plant to Europe from America in 1620. It comes from North America, where it grows on moist calcareous soils, from the lowlands to 1350 m above sea level, in deciduous forests from Pennsylvania to Georgia and Oklahoma. It is widely known in the culture of Western Europe, in some areas it is even mistakenly considered an indigenous species.
Although Robinia belongs to the same family as the acacia - Legumes, it is wrong to call it acacia. In the language of the ancient Hellenes - αγκάθι means a thorn. From here the Acacia tree got its name, and Robinia is called acacia by analogy because of the thorns.
Robinia, Latin - Robinia. Large trees 20-25 m high (can reach 30-35 m), openwork crown, sprawling. The kidneys are extremely small, not visible at all from a distance; annual shoots are granular, angular. Leaves are light green, unpaired, 20-30 cm long, consist of 7-19 elliptic leaves 2-4 cm long; autumn yellow.
The flowers are white, highly fragrant and rich in nectar, up to 2 cm long, collected in drooping racemose inflorescences 10-25 cm long.
Fruits - flat brown beans, 5-12 cm long, ripening by the end of September. The browned fruits are stored on the tree in the winter and next year. The seeds are narrow kidney, brown, dull, smooth, contain up to 12% semi-drying oil.
Annual growth is 60-80 cm in height and 20-30 cm in width.
The choice of place for planting robinia seedlings is determined by the need of plants in the light. For pink robinias, natural protection from the north wind is also desirable.
All robinias should be planted in the spring, before the buds open. The fact is that during autumn planting, the soil is too cold for the growth of the roots of these heat-loving plants and too wet, which is why the roots damaged by digging immediately begin to rot. In no case should you plant the robinia too deeply - all because of the same danger of aging. The combination of sand and compost with the indispensable addition of some alkaline substance - ash, dolomite flour, slaked lime, crushed stone is ideal as soil.
In general, these plants feel much better on the soils of the poor, but friable than on the rich and clay. When planting on a clay site, you can try, as in the cultivation of stone fruit crops, landing on a mound when the surface of the trunk circle after settling is higher than the soil level.
- Life form - Tree.
- Size - Height 20-25 m, width 12-20 m, trunk diameter up to 1.2 m.
- Crona - Round openwork.
- Leaves - Unpaired 20-30 cm long, light green, poisonous.
- Blossoming - In May-June, the flowers are white fragrant, collected in brushes 10-25 cm long.
- Fruits - Beans up to 12 cm.
- Features of growth - Annual growth from 20 cm to 1 m at a young age.
- Durability - Up to 100 years.
The plant contains Toxalbumin (Toxalbumin). The content in individual parts of the plant is different. Small doses can lead to indigestion, in large doses it is fatal.
- to the light - photophilous;
- to the soil - not demanding, but prefers light soils, tolerates salinization;
- to moisture - moderate watering;
- to the wind - not windproof;
- to temperature - frost-resistant.
City conditions - Smoke and gas resistant.
Decorative - Decorative during flowering.
Application - As a single tree, group plantings and alleys, it is able to strengthen the soil on the slopes.
The winter hardiness of various specimens of white acacia varies widely: from highly freezing, bushy, never flowering plants to powerful, flowering trees annually.
In Moscow, you can find many regularly flowering white acacias that suffer winter frosts and air pollution. By the way, with age, the resistance of plants to adverse winter factors increases.
White acacia is photophilous, but can tolerate partial shade. Soil prefers light, on compacted and undrained develops poorly, does not tolerate stagnant water. It is undemanding to soil fertility and itself remarkably improves them, enriching them with nitrogen. Resistant to soil salinization, to gases and smoke. Thanks to the branched root system resists strong winds, drought-resistant.
The main methods of propagation of white acacia are sowing seeds, separation of root offspring, vaccination (in the case of highly decorative forms and varieties).
Seeds are harvested in early November and stored in paper bags in the refrigerator. The best sowing date is spring, when leaves begin to bloom on adult acacia trees. To improve germination, it is necessary to carry out seed scarification (destruction of the dense shell): before sowing, the seeds are scalded with boiling water, immediately immersed in cold water and incubated for 12 hours. The treated seeds, without drying, are planted in moist nutrient soil (with the addition of compost and ash) on a bed in a greenhouse or open ground.
The optimum temperature for seed germination of Robinia pseudoacacia is 20–25 ° C. A bed with seeds and seedlings that have appeared is regularly watered, weeds are weeded. The distance between seeds during sowing should be at least 20 cm, since already in the first season white acacia plants can reach 0.5-1 m in height. The intensive growth of seedlings is facilitated by warm weather, regular watering, the complete absence of weeds, fertilizing and treatment of young plants with phytostimulants (Epin, Lariksin, Novosil, etc.).
In spring, plants that have reached a height of at least 50 cm and have wintered well are planted in a permanent place. In the next 10 years, under good conditions, the annual growth in height may exceed 1 m (in the middle lane, usually up to 1 m), then the growth rate gradually decreases.
White acacia does not tolerate soil sodding, so there should not be long-rhizome cereal grasses in the near-stem circle. Under the crown you can plant grassy ornamental plants or contain soil under steam. Apple trees, pears and other fruit plants cannot be planted next to white acacia - because of the highly developed root system, it can suppress them.
Types of Robinia
The genus Robinia belongs to the family Fabaceae (legumes) and includes about 20 species of woody plants growing in North and Central America.
Species Robinia pseudoacacia (Robinia pseudoacacia) has a number of highly decorative forms: weeping, pyramidal, spherical, umbrella, small-leaved, dissected leaf, golden and others. There are several varieties of white acacia: ‘Aurea’, ‘Frisia’, ‘Tortuosa’ and others.
White acacia trees are good in both single and group plantings. They are used to create alleys, picturesque groups, mixed or homogeneous rare-standing massifs. Since the plant tolerates a haircut well, it can be formed in the form of standard trees with a round or oval crown, make bosquets, hedges.
Sticky robinia (Robinia viscosa) - a tree up to 12 m high with a rounded crown. Shoots, leaves, inflorescences are sticky due to numerous glandular hairs. The leaves are large, bright green. The flowers are pink-violet, without aroma, located in numerous small erect brushes. Flowering is plentiful and long. Plants are less winter hardy and less drought resistant than white acacia, but can grow in the middle lane.
New Mexico Robinia (Robinia neomexicana) - a tree or shrub 6-12 m high. Intensively grows and early fruiting. The crown is broadly oval, often of irregular shape, the leaves are large, grayish-green. The flowers are pink-purple, large, without aroma. It blooms profusely and for a long time. In terms of resistance to adverse environmental factors, it is close to white acacia.
Robinia hairy (Robinia hispida) - a shrub up to 3 m high, forms abundant root shoots. Young shoots and petioles of leaves are densely covered with reddish hairs. The leaves are large, dark green. The flowers are pink or pink-purple, large, collected in racemose inflorescences. Blooms in bulk in June, then flowers can appear until September. Winter hardiness is moderate, that is, in cold winters it can freeze. But, like all the described robinias in general, it is well restored after frosts.
Growing any robinia is easy. Prerequisites will be only two - the abundance of the sun and the absence of stagnant groundwater at the landing site. If the site is located in a forest or in a swamp - you will have to say goodbye to the dream of this plant. We are waiting for your comments!