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The largest rhododendron (Rhododendron maximum) is a plant of the Heather family. Natural habitat: Asia, eastern North America, the Caucasus, Altai, Europe.
The garden crop was brought to the continent about 200 years ago. At the beginning of the 19th century, there were about 15 varieties of rhododendrons. However, the flowering shrubs were so captivating with 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
Rhododendron is the largest 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 in diameter is 1.1-1.2 m. The trunk is often curved and short. The annual growth is 10 cm.
The bark on the branches is brownish-red in color, with evenly spaced small cracks. Young shoots are covered with orange-red fibers. Branches aged 1 year or less are green.
The foliage is oblong or lanceolate.The length of the leaf blade varies from 10 cm to 30 cm, width 3-7 cm. The tips are pointed. Young leaves have a thick, reddish droop. Older foliage is dark green with a smooth surface. Petiole length 1.5-3 cm.
Flower color range: purple, light pink, sometimes white. The shape is bell-shaped with oval lobes. The size is 3-4 cm in diameter. The inflorescences consist of 16-24 flowers. The fruit of the largest rhododendron is an oval capsule 1 cm long.
Conditions for growing the largest rhododendron
To successfully cultivate 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.
- Replanting is not allowed during the flowering period and with the onset of frost.
- The shrub blooms at the age of 8-12 years.
- The period of main decorativeness falls on June-July.
- The fruits ripen by October.
- Planting type: group.
Planting and caring for the largest rhododendron
The description of the largest rhododendron variety indicates 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 a landing site
The planting site should be chosen based on the characteristics of the species. The largest rhododendron prefers drained, moist and humus-rich soil. The soil acidity level is 4.5-5.5. Peat should be added to neutral soils.
The largest shrub can be placed in an open clearing, but the favorable growing environment is partial shade. 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. The following species 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 measuring 60x40 cm is first prepared. 8 buckets of peat and 3 buckets of loam or clay are poured into the bottom of the planting hole. The mixture is compacted and left for two days to shrink.
Seedling preparation
Before planting in the ground, the largest rhododendron seedlings are inspected. Dry leaves and shoots are trimmed. The root system is carefully checked for rot. Shorten the length of the rhizome by 1-2 cm. Some gardeners advise holding a rhododendron seedling, the largest root formation stimulant, in a solution. After which the flowering shrub acclimatizes more easily in the new place and grows faster.
Landing rules
A hole 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 surface of the earth. Sprinkle soil on top and tamp lightly so that there are no voids left. Afterwards, the largest bush must be moistened abundantly. When the water is absorbed, the circle around the trunk 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 fertilizing
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 deterioration in the appearance of the shrub.
When the leaves of a garden crop of the largest variety lose turgor, this is a clear sign of lack of moisture. The volume of liquid should be enough to wet the soil by 20-30 cm. It is preferable to take purified water or rainwater. To soften the water, gardeners add a little peat to the container. The largest rhododendron should be moistened 2-3 times a week.
Flowering shrubs respond well to fertilizing. You can even add nutrients immediately after planting. It is recommended to choose liquid preparations containing horn meal and semi-rotted manure. Special fertilizers for rhododendrons and hydrangeas are available for sale.
Required feeding regime for the largest rhododendron:
- At the very beginning of spring, in March, organic and nitrogen-containing preparations are added 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 is enough.
The amount of nutrients is calculated per 1 square. m.
Trimming
Sanitary pruning of the largest rhododendron is carried out in early spring, before the buds open. Remove dry, broken, frostbitten shoots. Overall, the procedure should be minor. It is allowed to trim 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 torn off.This will provide an influx of new strength and save food for new inflorescences.
Preparing for winter
The largest rhododendron is a winter-hardy variety. Therefore, even when cultivated in central Russia, it does not need shelter for the winter. The bush will not be damaged, but annual shoots may freeze.
In November, the plant is prepared for wintering. If there has been no rain for a long time in the fall, then the largest rhododendron should be watered. 10-12 liters will be enough. If precipitation falls regularly, the bush should not be moistened.
Reproduction
The main methods of propagating garden crops:
- seeds;
- layering;
- cuttings;
- vaccination;
- dividing the bush.
The simplest and most natural method is propagation by layering. Throughout the season, the cuttings are watered and are located next to the mother bush. In the fall or next spring, the cuttings are separated and transplanted to a permanent place.
Seed method: the first year the seedlings are kept in a cool greenhouse, the next year they are planted in beds for rooting; this is an intermediate stage. Plants grow slowly. Flowering occurs in 6-8 years.
The vegetative method is also not easy. Cuttings take root from 1.5-4.5 months. Afterwards they are further grown in a greenhouse. In the spring they dig in the garden plot, seedlings take another 1-2 years to form.
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, and chlorosis.
When symptoms of cancer or spotting appear on the leaves, solutions of Bordeaux mixture and other copper-containing preparations are used. For chlorosis, “Iron Chelate” is used, which helps restore iron deficiency in the largest shrub. When cancer occurs, all affected areas are removed down to healthy tissue.
Garden crops can be attacked by harmful insects. Main enemies:
- spider mites;
- bedbugs;
- scale insects;
- snails, slugs;
- weevils.
The latter are destroyed with the drug “Diazinon”. They spray not only the bush, but also the ground underneath it. Slugs are removed manually. All other parasites die from Karbofos.
Conclusion
The largest rhododendron is an ornamental shrub that has appealed to many gardeners. But in order for the bush to be pleasing to the eye and fragrant, it is necessary to follow simple rules of care.
