Content
Japanese kerria is the only species in the genus Kerria. In its natural form, it is an upright shrub with carved leaves and simple 5-petal flowers. The decorative appearance of the bush contributed to the fact that the plant became widespread in gardens. The most popular among gardeners is the Japanese kerria Pleniflora with double flowers and beautiful carved leaves.
Description Kerry Japanese Pleniflora
Kerria grows up to 3 m in height. The branches are weak, arched. Under natural conditions, the shrub often grows clinging to rocks or other vegetation. In gardens, shrubs need support.
Leaves are simple, 3-10 cm long. The edges are double serrated. The upper side of the leaf is smooth, the lower one is covered with hairs. The wild form has golden yellow flowers.
At a young age, the bush has a pyramidal shape, but with age, the shoots lengthen and tilt downward, forming an arch.
Today there are several varieties of garden kerrias, and the most popular is Pleniflora. It is a dense shrub with double flowers, a mutational form of the common Japanese kerriya.
Single flowers are up to 3 cm in diameter and grow from the axils of the leaves. Lush flowering. Since the shoots are completely covered with yellow fluffy flowers, the leaves of Pleniflora are almost invisible at this time.
The bush blooms 2 times per season. The most lush bloom in late May and early June. Kerria blooms for the second time at the end of summer. Flowers appear on the shoots of the current and last years.
Kerria Japanese in landscape design
A photo of Japanese kerria in landscape design and a description of its unpretentiousness make the plant attractive for summer residents who want to create a hedge on their site. Thick bushes hide the rigid base of the fence well.
Since the bush grows up to 3 m, the height of the hedge can be varied. Most often in gardens, kerrias are cut at a level of 1 m from the ground.
When creating a composition of shrubs, kerria goes well with many plants:
- Japanese maple;
- meadowsweet;
- forsythia;
- rhododendron;
- Mahonia;
- bladderworm;
- spirea;
- action;
- Kuril tea;
- weigela;
- coniferous shrubs.
Japanese maple is a tree in nature. But in gardens, this is usually a vigorous, tall shrub with a height of 8-10 m.
A kerria bush surrounded by spring-autumn flowers will look good:
- catchment area;
- tulips;
- purple-blue egonichon;
- dwarf irises;
- hazel grouse;
- phlox;
- forget-me-nots;
- buzulniks;
- periwinkle;
- camellias.
There are a lot of options with flowers. You just need to choose the time of flowering of plants and a suitable color scheme. Moreover, the latter is usually a matter of taste for the designer and the customer.
Growing conditions for Japanese kerrias
Kerria is not afraid of the sun, but its flowers turn pale in direct sunlight, so it is preferable to plant kerria in the shade. The plant is hygrophilous, but does not grow in swamps, so stagnant water should also be avoided.
Kerria shoots are fragile and can break in strong winds.Planted with a solid wall in a green hedge or with other, sturdier bushes, kerrias will be protected from this problem.
It is better not to plant Japanese kerrias separately from other shrubs. Even provided that in landscape design, the combination of a bush covered with yellow flowers and forget-me-nots blooming on the ground looks very beautiful. But such a composition can only be created in a place closed from strong winds.
Planting and caring for the Japanese Pleniflora kerria
For planting kerrias, a site is selected that is not too shaded, but also not in the sun. The best option would be to plant a plant in the shade of trees with a not very dense crown or where the sun looks only at dawn or dusk.
Kerria propagates by cuttings, layering and young shoots. Since all these methods of reproduction involve the planting of an already "finished" plant with roots, it is necessary to prepare a pit with fertile soil for kerrias in advance.
Soil preparation
Kerria japonica grows best on loamy soils that can absorb and retain large amounts of moisture. If the type of soil on the site is different, Pleniflora will not die, although the flowering will not be so abundant.
But this is the "base" that almost cannot be changed. You can improve heavy soil by adding sand, and infertile by adding fertilizer. And also fill the hole for planting with soil, which will help the plant to take root. There are two recipes for pit soil:
- 3 parts of sand and 1 part of compost, sod land and humus, add 60-80 g of complex fertilizer;
- Mix garden soil with a bucket of compost, add a glass of ash and 60-80 g of complex fertilizer. The calculation is given for a pit measuring 0.6x0.6 m.
The second composition is more suitable for an area with loamy soil.
Preparation of planting material
If the Pleniflora seedling was bought together with the pot in the store, then no preparation is necessary. It is enough to shake the kerria out of the pot along with a lump of earth and plant it in a permanent place using the transshipment method. The same applies to cuttings that have been pot-rooted at home.
When buying a seedling from hands with a bare root system, the plant is examined and dried and rotten parts are removed. You can put the seedling in a solution with a root growth stimulator for several hours.
When self-excavating planting material (propagation by layering), you need to try to remove the seedling along with the ground so that damage to the young root system is minimal.
Landing site preparation
A hole with a diameter of 60 cm and the same depth is dug in the selected area. Soil is poured into the pit so that a slide forms. Later, the soil will settle and level with the ground.
If the landing site is too wet, the pit is made deeper and a thick layer of drainage material is poured onto the bottom: broken brick, pebbles, etc.
If you carry out all the work 6 months before planting, not only will the soil in the hole be compacted, but fertilizers will also be more evenly distributed. For Japanese kerrias, a large amount of fertilizer in the first 2 years after planting can be dangerous.
Landing rules
Planting kerrias is carried out in the fall at least a month before the onset of frost or in the spring before the start of sap flow. For almost all plants, autumn planting is considered less traumatic.
When planting by transshipment in compacted soil, a recess is made the size of a lump of earth from a pot. They put a lump on the bottom of the recess and sprinkle it with soil for stability.
When planting a Pleniflora seedling with a bare root system, it is necessary to ensure that the roots of the bush do not break. In this case, it is better to carry out the planting together: one person holds the plant "in the air", the second covers the roots with earth.
After planting, the ground is lightly tamped and the seedling is watered. The first 2 weeks the soil under Pleniflora is kept constantly moist.
Watering and feeding
Kerrias need to be watered regularly during flowering and dry periods. Pleniflora is watered once a week. In rainy years, Japanese kerria does not need watering. In an average year, Japanese kerrias are watered 2-3 times per summer, but abundantly.
Feeding is a little more complicated. Kerria is considered an unpretentious shrub that does not require a large amount of fertilizer. Some gardeners recommend not feeding Pleniflora at all for the first 2 years, so as not to burn its roots.
But for the rest, the rules for fertilizing are the same as for other plants: you can add fertilizers before winter, or with spring watering.
Sometimes kerrias are fed in spring with mullein infusion, and after summer pruning with complex fertilizers.
Pruning
The rules for pruning Pleniflora are simple: spring sanitary and after the first flowering. Sanitary pruning is carried out in early spring, before the buds have time to swell. All dead and diseased shoots are removed. If necessary, thickening stems are cut, annual branches are pruned to ¼-⅓ lengths.
Re-pruning is done in order to make Pleniflora bloom more luxuriantly a second time. If such a goal is not worth it, the kerria may not be cut a second time.
In the second pruning, remove those branches on which there were flowers. They are cut to the shoots on which there were no flowers in the spring. In this case, new flowering shoots will grow over the summer, and Pleniflora will bloom magnificently again.
In kerria, shoots grow until mid-autumn, and for normal wintering, these shoots must ripen.
Preparing for winter
The winter hardiness of the kerria of the Japanese Pleniflora is not very high, although in the southern regions it does not need any shelter for the winter. In a windless place, she can overwinter without shelter.
If it is required to close Pleniflora for the winter, then airtight materials cannot be used. Tarpaulins or plastic wrap will not work. Nonwovens will fit: lutrasil, spunbond and others similar. But even they are not always needed. Sometimes you can get by with spruce branches and snow.
The shoots are tied and, if possible, bend to the ground. Then they are covered with spruce or pine branches. This operation is carried out when the air temperature drops below 0. As soon as the opportunity arises, the kerria is covered with snow.
Pleniflora does not like stagnant air and may die.
Reproduction
Kerria japonica can produce small seeds of 4-4.5 mm in size. But reproduction in this way is not practiced in horticulture due to its low efficiency. Usually Pleniflora is propagated in 3 ways:
- dividing the mother bush;
- cuttings;
- layering.
The division of the mother bush is just so called. In fact, in spring or autumn, lateral shoots are carefully dug up and planted in the prepared pits according to the usual scheme.
Propagation by cuttings
In late spring, annual, but already lignified shoots are cut into pieces 6 cm long. The cuts are made oblique. Cuttings are buried in a shaded place and watered well throughout the summer. In September and early October, rooted cuttings are planted in open ground. In a permanent place, new plants are planted in the spring of next year.
Breeding by layering
In early spring, in parallel with sanitary pruning, grooves are made in the ground next to the Pleniflora bush. Growing shoots are neatly laid there, without cutting them off from the bush, and pinned to the ground.
After 15 days, new shoots appear from the buds of the shoots pinned to the ground. When the shoots become 10-15 cm high, the grooves are sprinkled with earth. Only the tops of new shoots should remain on the surface. In the spring of next year, you can already plant young bushes in a permanent place.
Diseases and pests
Kerria Japanese is not very susceptible to diseases and pests. At least, the usual pathogenic microorganisms do not touch kerria.But since 2014, the Horticultural Society of Great Britain began to receive reports of cases of kerria diseases. Signs of the disease are red spots on the leaves and damage to the stems. The disease results in discoloration and drying of the color and possibly death of the entire bush.
This disease was known in the United States as kerria leaf and stem rot, but has not previously been reported in Europe. The disease is caused by the fungus Blumeriella kerriae, which affects only Japanese kerria.
Conclusion
Kerria Japanese Pleniflora can become a real decoration of the garden. She is not only beautiful during the entire growing season. She is also undemanding to care and soil. It is easy to propagate by creating a whole green hedge from one bush.
