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The largest rhododendron (Rhododendronmaximum) is a plant of the Heather family. Natural habitat: Asia, east of North America, Caucasus, Altai, Europe.
Garden culture was brought to the continent about 200 years ago. At the beginning of the nineteenth century, there were about 15 varieties of rhododendrons. However, the flowering shrubs were so captivated by their beauty that the process of mass breeding of new varieties began. In 2015, 3,000 varieties appeared, among which the largest rhododendron stands out.
Description of the largest rhododendron
The largest rhododendron is an evergreen shrub. The height can reach 8-10 m. In Moscow it grows up to 1 m. The crown is planted low. The shape is spherical, the size is 1.1-1.2 m in diameter. The trunk is often curved, short. The annual growth is 10 cm.
The bark on the branches is brownish-red, with evenly spaced small cracks. Young shoots are covered with orange-red villi. Branches at the age of 1 year or less are green.
The foliage is oblong or lanceolate. The length of the leaf plate varies from 10 cm to 30 cm, the width is 3-7 cm. The tips are pointed. Young leaves have a dense, reddish prolapse. Older foliage is dark green in color with a smooth surface. The length of the petiole is 1.5-3 cm.
The color range of flowers: purple, light pink, sometimes white. Bell-shaped with oval lobes. Size 3-4 cm in diameter. Inflorescences consist of 16-24 flowers. The fruit of the largest rhododendron is an oval box 1 cm long.
Growing conditions for the largest rhododendron
For the successful cultivation of the largest rhododendron, it is important to know the basic characteristics and life cycles of the plant.
- Optimal planting dates: early spring or early autumn.
- Transplanting is not allowed during the flowering period and with the arrival of frost.
- The shrub blooms at the age of 8-12 years.
- The period of the main decorative effect falls on June-July.
- The fruits ripen by October.
- Planting type - group.
Planting and caring for the largest rhododendron
In the description of the largest rhododendron variety, it is indicated that the plant is durable. In nature, it can grow up to 100 years. With proper planting and timely care, a flowering shrub can grow for more than one year.
Selection and preparation of the landing site
The landing site should be chosen based on the characteristics of the species. The largest rhododendron prefers drained, moist and humus-rich lands. The acidity level of the soil is 4.5-5.5. Peat should be added to neutral soils.
The largest shrubs can be placed in an open meadow, but a favorable growing environment is partial shade. The neighbors of the largest rhododendron can be trees with a powerful root system that goes deep into the ground: larch, oak, pine. Among the garden trees are pear and apple trees. Such breeds are unfavorable: linden, maple, willow, poplar. Their roots are located at the same depth as the largest rhododendron. This means that there will be competition for the extraction of nutrients.
A hole of 60x40 cm is preliminarily prepared. 8 buckets of peat and 3 buckets of loam or clay are poured into the bottom of the planting pit. The mixture is tamped and left to shrink for two days.
Seedling preparation
Before planting in the ground, the seedlings of the largest rhododendron are examined. Cut off dry leaves and shoots. The root system is carefully checked for rot. They shorten the length of the rhizome by 1-2 cm. Some growers advise holding the seedling of the rhododendron, the largest root stimulator in the solution. After that, the flowering shrub is easier to acclimatize in a new place and will grow faster.
Landing rules
A recess is made in a pre-prepared hole so that the roots of the plant fit completely. The root collar of the largest rhododendron should be above the ground. Sprinkle on top with soil and tamp lightly so that no voids remain. After the largest bush must be moistened abundantly. When the water is absorbed, the near-stem circle is mulched with oak leaves, peat or pine needles. The thickness of the layer of natural material is 5-6 cm.
An example of planting the largest rhododendron is shown in the photo.
Watering and feeding
The largest rhododendron is considered a moisture-loving plant and requires regular watering. However, excess moisture and poor-quality water can lead to rotting of the root system, and a deterioration in the appearance of the shrub.
When the leaves of the horticultural crop of the largest variety lose their turgor, this is a clear sign of a lack of moisture. The volume of liquid should be enough to wet the soil by 20-30 cm. It is preferable to take purified or rainwater water. To soften the water, gardeners add a little peat to the container. The largest rhododendron should be moistened 2-3 times a week.
The flowering shrub is good for feeding. Nutrients can be added even immediately after planting. It is recommended to choose liquid preparations containing horny flour and semi-rotten manure. There are special fertilizers on sale for rhododendrons and hydrangeas.
The required feeding regime for the largest rhododendron:
- At the very beginning of spring, in March, organic and nitrogen-containing preparations are introduced at the rate of 50 g;
- after flowering, in early June mineral fertilizers are used: 20 g of potassium sulfate and superphosphate, 40 g of ammonium;
- in July, 20 g of potassium sulfate and superphosphate are enough.
The amount of nutrients is calculated per 1 sq. m.
Pruning
Sanitary pruning of the largest rhododendron is carried out in early spring, before bud break. Remove dry, broken, frostbitten shoots. In general, the procedure should be minor. It is allowed to cut off no more than ¼ of the bush. A month later, the process of sap flow and the recovery process begins.
The largest rhododendron blooms throughout the season. Therefore, after wilting, the buds should be cut off. This will provide an influx of new strength, and save food for new inflorescences.
Preparing for winter
The largest rhododendron belongs to the winter-hardy species. Therefore, even with cultivation in Central Russia, it does not need shelter for the winter. The bush will not suffer, and annual shoots may freeze.
In November, the plant is prepared for wintering. If in the fall there was no rain for a long time, then the largest rhododendron should be watered. 10-12 liters will be enough. If precipitation fell regularly, then the shrub should not be moistened.
Reproduction
The main ways of breeding garden culture:
- seeds;
- layering;
- cuttings;
- vaccination;
- dividing the bush.
The simplest and most natural method is propagation by means of layering. Throughout the season, the cuttings are watered, it is located next to the mother bush. In the fall or next spring, the layers are separated, transplanted to a permanent place.
Seed method: the first year the seedlings are in a cool greenhouse, the next they are planted in the beds for rooting, this is an intermediate stage. Plants grow slowly. Flowering occurs at 6-8 years.
The vegetative method is also tricky. Cuttings are rooted from 1.5-4.5 months. After that they are still grown in a greenhouse. In the spring, they drop it in the garden, the seedlings are formed for another 1-2 years.
Diseases and pests
As a result of poor ventilation and lack of adequate air access to the root system, the largest rhododendron suffers from fungal diseases such as cancer, rust, leaf spot, chlorosis.
When symptoms of cancer or spotting on the leaves appear, solutions of Bordeaux liquid and other copper-containing preparations are used. When chlorosis is used "Iron Chelate", which helps to restore the lack of iron in the largest shrub. When a cancer occurs, all affected areas are removed to healthy tissue.
Horticultural crops can be attacked by harmful insects. Main enemies:
- spider mites;
- bedbugs;
- scabbards;
- snails, slugs;
- weevils.
The latter are destroyed with Diazinon. They spray not only the bush, but also the ground under it. Slugs are removed manually. All other parasites are killed by Karbofos.
Conclusion
The largest rhododendron is an ornamental shrub that many gardeners like. But in order for the bush to please the eye and smell sweet, it is necessary to follow simple rules for care.
