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Douglas Spiraea is a representative of the Rosaceae family, which includes more than a hundred species that differ in growth and color. The habitat of the ornamental shrub is Asia (Himalayas), part of Mexico, found in mountainous regions, forest-steppes. The plant is frost-resistant, tolerates drought well. On the territory of the Federation it is used as an element in the design of the site.
Description of Douglas’ spirea
Spirea Douglas (spiraea Douglasii) refers to deciduous plants with a long flowering period. The first flowers appear in July, the peduncle ends in a temperate climate after a month and a half, in the South – until the end of autumn. External features of spirea:
- Shrub 1,5 m high, gives a significant number of erect processes. The structure of the stem is rigid, strong, flexible, light brown in color with a burgundy tint. Branches with dense pubescence.
- Spiraea has oblong leaves up to 10 cm long. The plate is saturated green in color, with a two-tiered structure. The lower part is oval in shape, smooth along the edges, framed from the middle by a jagged structure, tapering at the top. The reverse side of the leaf is silvery with a strong edge.
- The root system is fibrous, dense, well expanded in breadth.
- Small multiple flowers of a dark pink hue, collected in panicles (up to 15 cm). The pyramidal inflorescence is formed at the top of the stem. The protruding white stamens give decorativeness, the panicle looks like in an openwork cocoon.
Douglas shrub grows fast. After 3 years reaches its maximum height, begins to bloom.
Spirea Douglas in landscape design
This type of spirea is the most popular among professional designers and amateur gardeners. A variety of Douglas is planted in compositions, as a background accent, as a decoration for alleys, near water bodies.
The use of Douglas spirea (pictured) in the landscape design of the site:
- in the form of a composition in the center of a flower bed;
- to highlight a certain part of the garden;
- distribution along the edges of the garden path creates a visual perception of the alley;
- as a hedge to designate areas on the site;
- to create a background near the wall of the building.
In combination with undersized flowers, the plant is used in rockeries to draw attention to a particular composition of stones. Distributed along the edges of the alpine hill.
In urban recreation areas, squares, parks, Douglas’ spirea is planted as a hedge near sanitary zones, benches, along alleys. Harmoniously combined with coniferous trees, juniper, Japanese pine. Douglas spirea, placed under a maple, will favorably emphasize the foliage of the tree.
Planting and caring for Douglas spirea
Spiraea Douglasii is a perennial, summer-flowering plant, determined to a permanent place in early spring, when the soil has thawed so much that planting can be carried out, or in autumn, until the sap flow has ended and it has not shed its foliage.
Preparation of planting material and site
Douglas spirea is a heat-loving plant that can grow in one place up to 15 years, this factor is taken into account when choosing a site. The bush can be in the shade for a certain time without compromising flowering, for example, several hours a day. Permanent shading and dampness are unacceptable for the species.
Soils for planting choose fertile, loose, well-drained. The composition of the soil is slightly acidic or neutral. The roots of the plant are fibrous, prone to decay. If there is groundwater in the area close to the surface, the shrub will die. An unsuitable place for landing is a lowland with a lack of lighting and water accumulation.
Planting material is chosen with a well-developed, healthy root system. Damaged areas or dry fragments are cut out before planting. The seedling is immersed in a solution of manganese for 2 hours, then placed in a root growth stimulant for a day. Treated with a fungicide.
Rules of landing
If the Douglas spirea is part of the composition, it is planted in the hole. For a hedge, seedlings are placed in a trench, the depth in both cases is 50 cm. The width of the hole is 15 cm larger than the root system, the distance between the bushes is 60 cm. Algorithm of actions:
- A twenty-centimeter layer of drainage (pebbles, gravel) is laid at the bottom.
- The soil mixture is poured on top, consisting of equal parts of the fertile layer and compost.
- A spirea is vertically installed in the middle, the roots are distributed, covered with soil. The root neck should be 3 cm above the surface.
- The soil is compacted, watered, mulched with peat.
Watering and top dressing
Spiraea Douglas does not require constant watering, twice a month is enough, but with plenty of water. If the weather is dry, irrigation is increased. Do not allow the soil to dry out, as well as waterlogging. Be sure to loosen the soil and remove weeds.
Top dressing is applied in the spring at the beginning of the growing season, diluted in water with organic matter, after two weeks with superphosphate agents. An effective effect on the growth of shrubs is provided by the Kemira Universal fertilizer applied under the root.
Douglas spirea pruning
Spiraea Douglas blooms in summer, its crown is formed in spring, before the leaves appear. Remove old branches and young growth, which thickens the crown. Cut out frozen shoots, shorten the tops. The young plant is cut off the upper part to well-developed buds.
After four years of growth, the Douglas spirea is subjected to cardinal pruning, leaving 25 cm from the root. The shrub will quickly restore new shoots without sacrificing flowering. Trimming the tops is impractical; the spirea will form thin stems with small inflorescences. Pruning activities continue every year. If the Douglas spirea gives weak shoots, the plant is transplanted to another site.
Preparation for winter
The frost-resistant culture of spiraea Douglasii, grown in the European zone, tolerates temperature drops well if certain preventive measures are taken. The root system of the plant is superficial, so shelter is necessary. The root circle is mulched with dry leaves, peat or pine needles, and the Douglas spirea is first spudded with soil by 30 cm. There is no need to bend down and cover the branches, in the spring the bush will quickly recover, it is better to tie the shoots into a bundle.
Reproduction
Douglas spirea is propagated on the site by several methods: seeds, division, cuttings, layering. Planting material is taken from the mother plant (at least 4 years old). Spiraea is rarely propagated by seeds, the process is long, not always the planting material gives the required number of seedlings. This method is used in the hybridization of new ornamental varieties.
Productive and labor-intensive methods of reproduction:
- Layers. Lateral branches are bent to the ground, fixed and sprinkled with soil. Work is carried out in early spring. Over time, the root system will form from the kidneys. After the appearance of two or more young sprouts, the branch is cut off from the bush, removed from the soil, divided by the number of seedlings formed. Douglas spirea has a good survival rate, the young shoots are immediately planted in a permanent place of growth.
- By dividing the bush. This method is used in the fall, approximately in September, so that there is enough time for the adaptation of the root system. Spirea is removed from the ground, divided so that each part consists of several shoots and a strong root lobe.
- Cuttings. In early September, 15 cm fragments are cut from an annual shoot. Placed in a container with soil at an angle of 400, cover with a film with holes for access to oxygen.
In winter, containers with Douglas spirea cuttings are covered with leaves, sprinkled with snow. In the spring, cuttings are opened, planted in early June.
Diseases and pests
Douglas spirea practically does not get sick. The most common pest that parasitizes the plant is the spider mite. The female of the insect hibernates under the foliage that has fallen from the bushes, in the spring it lays eggs on the leaves, up to 10 clutches per season. Affected leaves die and fall off. Vegetation slows down, Douglas’ spirea loses its decorative appearance. For preventive purposes, they remove fallen leaves, loosen the soil. In hot weather, completely irrigate the bush. Processed with means: “Acrex”, “Keltan”, “Phosfamide”.
Aphids are less common, they feed on spirea juice, the colony grows rapidly. Without timely measures taken, the plant will not give flowers, throw off leaves, stop growing. The pest is neutralized with drugs: Pirimor, Actellik, Bitoxibacillin.
Conclusion
Spiraea Douglas is a perennial shrub widely used for the design of personal plots, urban recreation areas. The frost-resistant plant is distributed throughout Our Country. It is undemanding to care, tolerates drought well. Deciduous shrub blooms with cone-shaped, large inflorescences of a dark pink hue.