When to Cover Rhododendrons for the Winter
Rhododendron is an evergreen or deciduous garden shrub, which blooms in spring. In winter, some varieties require special care. Properly prepare the plant for the onset of frost will help simple tips.
Do I need to cover rhododendron for the winter
Depending on the degree of resistance to frost, some varieties of the plant may require shelter for the winter. Varieties of rhododendron are divided into evergreen and deciduous.
Popular representatives of the first group:
Among deciduous subspecies, Canadian, Kamchatka, yellow, Japanese rhododendron are distinguished. The colors of their varieties range from white to bright purple. Almost all of these varieties are resistant to cold, however, it is recommended to additionally warm the root neck.
Important! Rhododendron varieties (as well as azaleas belonging to its species) have varying degrees of frost resistance, therefore, before choosing a seedling, it is advisable to know in advance the features of a particular specimen.
In the northwestern and central region of Russia, in particular in the Moscow region, where the cold weather comes quite early, you need to prepare the plant for wintering in advance. This must be done during the autumn period, from October to November, when the temperature dropped below -10 ° C. Before this time, it is not recommended to close the bushes, since the weather conditions are not stable at the beginning of autumn, and temperature differences are possible. It is desirable to shelter with the onset of steady frost.
Additional warming is necessary for plants that have low or medium (up to -30 ° C) resistance to frost. These include cultivars of rhododendron, bred by breeding. If you allow them to winter in the open air, shoots and roots will get frostbite, as a result of which the plant may die. Flowering buds may not cause flowering. Natural specimens tolerate frosts well and do not need artificial shelter.
Winter shelter should be reliable, but easy. This is important, as too dense and heavy materials can damage the delicate buds of the bush.
For quality shelter, the following materials are suitable:
- dry corn stalks;
- thermal insulation flooring;
- protective constructions.
Pine or spruce spruce branches - a natural material that is great for sheltering plants for the winter. It is used to protect frost-resistant varieties. Lapnik passes air well, which facilitates the access of oxygen to the plant. Also, with this material, you can wrap the near-stem circle of young rhododendrons, so that after planting they are protected from the cold.
Dry corn stalks
Corn stalks can cover the soil around the plants for additional warming. This method of protection is suitable for both frost-resistant varieties and evergreen. Thermal insulation of the soil allows you to keep the heat necessary for the roots and prevent cracking of the upper layer of the earth. The material must be laid out in a sufficiently large layer, about 30 cm. With dry corn stalks, you can completely cover the undersized varieties.
Sawdust is used to warm and mulch the soil in which rhododendron grows. To do this, they sprinkle abundantly around the trunk circle. This method will help the roots get enough moisture. Also, the earth will retain the necessary heat and protect the root system from frostbite.
Thermal insulation flooring
Thermally insulated floorings are made of a special material that allows you to keep warm. They are suitable for sheltering plants with low resistance to frost. Floorings cover frames, inside of which there are bushes. Material can be purchased at a hardware store. Covering them with the frame, from below it is necessary to leave a few centimeters in stock.
Frames are installed before stable frosts begin. Until the ground is frozen, the plant must be covered with a protective structure.
Important! The distance between the frame and the plant should be at least 35 cm.
It can be installed as follows:
- Build a hut. To do this, you need to drive four pegs around the bush.
- Make an arcuate coating. Around the bush you need to install one end of a flexible and long enough rod so that it completely covers the plant. Dig the other end from the opposite side. Then, in the same way, you need to install the second rod, only at the same time it should be located across the first - "crosswise".
- Use a plank or stool. To install the frame in this way, you need to install four medium-sized metal sticks around the bush and fix wooden planks on top (or just turn the stool over).
Shelter implies certain rules for protecting the plant from the cold. Deciduous and evergreen species should be closed in different ways, since they have a different degree of resistance to frost.
The installation scheme of a protective shelter for evergreen varieties involves the following rules:
- With the onset of cold weather, in late November, you need to bend the branches of tall plants to the ground and fix it.
- Cover the trunk circle with spruce branches and dry corn stalks.
- Install the frame and cover it with insulating flooring so that the lower edge of the material is raised. This is necessary so that the plant that has not yet fallen asleep continues to provide gas exchange.
- When a stable low temperature (-10 ° C) is established, the plant should be completely closed by lowering the lower edge of the flooring and fixing the film on it. Such a measure will protect the bush from melting snow.
- The bottom edge of the flooring should be sprinkled with earth and put bricks on it for reliable fixation.
Deciduous species are enough to wrap at the base with sawdust and corn stalks. The plant itself needs to be covered with spruce branches, after pressing the stems to the center and bandaging them.
Video: How to Cover Evergreen Rhododendrons for the Winter
Before covering the plant for the winter, it is necessary to carry out a number of preparatory measures. The procedure includes top dressing and pruning. These measures contribute to the full relaxation of the plant. Fertilizing will provide nutrition during dormancy and increase frost resistance, and pruning branches will slow down sap flow, which will help the bush to accumulate the strength necessary for flowering. Also, the bush is trimmed for prevention. Start preparing the plant for wintering in the fall.
Did you know? Canadian rhododendron juice in 20 minutes completely stops the process of fermentation in wine.
You need to feed the shrub in mid-autumn, after flowering is completed. Fertilizers for rhododendrons should contain equal proportions of potassium, phosphorus and sulfur. It is important to make sure that nitrogen is not part of the fertilizing, as it stimulates the growth of new shoots, which is extremely dangerous for the plant during the cold season. It is recommended to spray the bush in early autumn with a 1% potassium solution. To prepare the fertilizer, you need to dilute in 10 l of water 8 g each of potassium sulfate and phosphate. Proportions are calculated for one plant.
In the fall, all faded inflorescences should be removed to avoid decay, which can lead to the spread of infection. Next, you need to completely cut off all dry and weakened stems. The remaining shoots need to be shortened by about a third. The old shrub can be freshened by completely cutting off its branches, leaving only 40 cm high stumps. The cut points must be treated with crushed activated carbon or ash.
During the dormant period, while the plant is in shelter, there is a risk of propagation of pests, which mainly winter on the stems of the bush. Also, warming for the winter creates suitable conditions for the activation of fungal diseases. To avoid infection of the shrub, it is necessary in the autumn, after pruning, to spray it with a fungicide solution ("Topaz", "Skor", "Horus"), which should also be abundantly watered. Next, you need to withstand some time, so that the earth is saturated with the product and, after drying, you can cover the rhododendron for the winter.
When to open in the spring
In the spring, after the earth has warmed enough, you can begin to temper the bush. This should be done gradually to allow the plant to adapt a little to the intense effects of spring sunlight. If you skip this step and immediately remove the shelter, a bush that has weakened after wintering can get burns. It is recommended to remove the protective structure in the morning and evening hours, increasing the time spent by the rhododendron in the open every day.
After the shelter is completely removed, you need to remove mulch from the near-trunk zone (sawdust and dry corn stalks). Then water abundantly and loosen the soil. Next, a routine inspection is necessary. If there are signs of wilting on the foliage and shoots of evergreen varieties, the plant does not have enough moisture. Watering in this case needs to be increased.
If signs of disease or pests are detected, it is important to immediately treat the shrub with a fungicide solution by spraying and watering it. Next, you need to feed the awakened bush with fertilizers with a high nitrogen content, which stimulates the formation of young shoots.
Did you know? Rhododendron includes at least 1000 varieties. On their basis, breeders have bred about 12,000 decorative varieties.
Rhododendrons, or azaleas, are the lushly flowering shrubs that adorn gardens and adjoining territories. Evergreen and deciduous varieties have varying degrees of resistance to frost, so some of them require additional insulation for the winter. Following winter care rules will ensure abundant flowering and harmonious growth of these luxurious bushes.