Barberry Thunberg Cobalt is an ornamental shrub of small, almost dwarf growth, used for landscaping the lower tier. It is used to create low hedges, curbs and flower beds. The main feature of the Thunberg Cobalt barberry is the high density and spreading of the bush.
Description of barberry Cobalt
Barberry Thunberg Cobalt was bred in the middle of the last century in Holland. This ornamental plant is quite compact in size, reaching a height of no more than 50 cm. In rare cases, its height reaches high values, however, one of its main characteristics, the density of the bush, is lost, and the Thunberg barberry Cobalt becomes less decorative.
Barberry Thunberg Cobalt is grown exclusively as a dense plant with emerald green foliage. It is used as a curb shrub. In some cases, the Thunberg Cobalt barberry can be used as a single standing. Often a similar technique is used in the design of low flower beds or rock gardens.
Shoots of Cobalt barberry are short, densely covered with leaves and small thorns. Cobalt leaves stick around the shoots and are located oppositely on them. The leaves can be up to 2 cm long, they are elongated and slightly pointed at the end. As they grow, this sharpening gradually rounds off.
The flowering of the Thunberg Cobalt barberry begins in mid-May and lasts about two weeks. The flowers are in the shape of pale yellow or lemon bells. Their number is quite large: one shoot can have up to 2-3 dozen flowers.
Like most members of the Barberry family, Cobalt can change foliage color depending on the season. From early spring to mid-autumn, the color of the leaves has an emerald hue, changing with the onset of cold weather to orange-yellow. Additional decorativeness in the autumn months to the Cobalt Thunberg barberry is given by berries of a bright red color. Barberry Thunberg Cobalt also has a lot of fruits, since almost all flowers are tied.
With the arrival of the first frost, green leaves that did not have time to change color to orange fall off. Photo of barberry Cobalt is presented below:
Barberry Thunberg Cobalt has low growth rates and practically does not need formative pruning, but it tolerates it perfectly, and its crown can be formed at the request of the owner.
Barberry Thunberg belongs to winter-hardy and frost-hardy plants.
Planting and caring for barberry Thunberg Cobalt
Caring for the Thunberg Cobalt barberry is simple and does not require any complex skills or abilities. Even inexperienced growers can grow this ornamental shrub.
The most important thing in growing it is to avoid excessive thickening. However, frequent pruning is also undesirable for the plant. Given the low growth rates of barberry, the formation of the crown of the plant once every 1-2 seasons will be optimal.
Seedling and planting plot preparation
Despite the fact that the Thunberg Cobalt barberry is unpretentious, it will best be in a sunny area. Cultivation in partial shade is also allowed, but the shade is extremely undesirable, in it the growth rate of the shrub will be practically zero.
In addition, only in sunny areas will there be a change in leaf color by the autumn season. A plant in partial shade is likely to have orange foliage in autumn only around the perimeter of the leaves.
Barberry is undemanding to the soil: it does not care about its fertility or hardness. For a faster adaptation of a young plant, preference should be given to light soils with a medium or low degree of moisture.
Important! Cobalt does not like Thunberg barberry too wet areas. Its root system tolerates drought much better than strong moisture.
Preliminary preparation of the site for planting involves digging holes with a depth of about 40 cm and a diameter of no more than 50 cm.A soil consisting of the following components should be laid at the bottom of the hole:
- garden land - 2 parts;
- humus or compost - 1 part;
- sand - 1 part.
The height of the nutrient soil should be from 1/3 to half the depth of the hole.
It is recommended to lime acidic soils with ash or lime (in the amount of 200 g or 300 g for one bush, respectively).
Any preliminary preparation of seedlings before planting is not required.
Planting should be done either in early fall or late spring. It is desirable that there are no leaves on the seedlings, but at least 3-4 vegetative buds on each of the shoots.
Planting of plants is carried out in such a way that the distance between the bushes is from 50 to 80 cm. In this case, it is advisable to add a complex fertilizer for ornamental plants, consisting of potassium, nitrogen and phosphorus, to the holes on poor soils.
The seedling has a sufficiently developed root system, which must be carefully laid on a layer of fertile soil previously introduced into the hole, straighten the root layers and carefully sprinkle it with garden soil.
After that, the soil is lightly compacted and watered.
Watering and feeding
Watering is carried out as the soil dries up. In this case, you should not "fill" the plant too often - just one plentiful watering for 1-2 weeks.
The first top dressing is done in the second year after planting the Cobalt Thunberg barberry. In the spring, nitrogen fertilizer is applied, consisting of 20 g of urea, dissolved in 10 liters of water per bush. At the end of the season, the bush is mulched with peat. Then this procedure is repeated annually. No other dressing is required for barberry.
The main pruning that the plant needs is sanitary, it is carried out after wintering. At the same time, sick, old and dried shoots, as well as shoots growing "inside the bush" are removed as standard.
Formative pruning is only relevant for plants that act as hedges. They are usually cut 2 times a season (beginning and end of summer). In other cases, formative pruning is performed no more than once every 2 years.
Preparing for winter
Plants over 3 years old do not need to be prepared for winter, since they are able to tolerate frosts down to -35 ° C without shelter. Young plants should be wrapped in polyethylene for the winter and sprinkled with a layer of foliage 20-30 cm high. And as soon as the first snow falls, sprinkle on top with snow.
However, in the spring, in order to avoid over-heating of the plant, it is better to remove this "thermal protection" already at the first thaw.
Barberries reproduce in standard ways:
- dividing the bush;
- using cuttings;
Unlike most perennials, the Thunberg Cobalt barberry tolerates reproduction by dividing the bush very poorly. Any damage to the rhizome that "goes wrong" will be fatal to the plant. Therefore, you should try to divide the rhizome along the thinnest roots, without touching the main root process.
Dividing methods by layering or cuttings are preferred. On average, in the 5th year of life, from 2 to 5 layers appear in the barberry, which are perfectly transplanted to a new place and begin to bloom after 1-2 seasons.
Cuttings are made from lush shoots and grown according to the standard method using very liquid soil. At the same time, it is desirable to treat them with a rooting stimulator, for example, epin.
Growing with seeds is also not a problem as the seeds are very germinating. The main thing is that they go through stratification. It is done as follows: the seeds collected in the fall are stored until early April in the refrigerator at a temperature of no more than + 5 ° C. Then they are planted without any additional processing in a greenhouse or on open ground.
Diseases and pests
The plant has increased resistance to many diseases inherent in ornamental plants, however, there are several types of diseases and pests that can cause serious damage to the Thunberg Cobalt barberry.
The most severe disease threat is powdery mildew. This fungal disease on barberry behaves exactly the same as on any other plant: the symptomatology manifests itself in the form of a powdery bloom, first on the lower part of the leaves, then on their entire surface, shoots and flowers.
The fight against powdery mildew is carried out using a sulfur-lime mixture and a solution of colloidal sulfur. In this case, the entire affected plants should be sprayed after 2 days on the third within 20 days until the symptoms of the disease completely disappear. Moreover, as soon as powdery mildew is found, the damaged shoots must be cut to the very root and burned.
The main pest of barberry Cobalt is a highly specialized parasite - barberry aphid. Its behavior is standard for all representatives of aphids: clinging to leaves and shoots, small insects suck out the juices of the plant, from which it begins to dry out. Finding barberry aphids is quite problematic, since it is extremely small in size.
If aphids are found, either spray the affected plants with a solution of laundry soap (30 g of soap per 1 liter of water), or use a tobacco solution - 50 g of makhorka per 1 liter of water. Spraying is carried out daily until the complete disappearance of pests.
Another unpleasant pest that can infect barberry is the flower moth. To combat it, insecticides are used (for example, Chlorophos or Decis).
Barberry Thunberg Cobalt, due to its decorative properties, is widely used in the design of gardens, home gardens, parks and flower beds. It is the ideal plant to fill the bottom tier in any landscaping. Growing Cobalt barberry is quite simple and can be recommended even for novice florists.