The beautiful rhododendron has long been a frequent guest in our gardens.
However, not everyone still knows how to properly care for this plant. We will tell you in detail what work needs to be done at the end of the season and how to properly prepare rhododendron for winter.
The preparation for winter of deciduous and evergreen rhododendrons differs little from each other. The only difference is that the deciduous varieties do not need to be covered and need less water, since there is no evaporation of moisture from the leaf plates. And everything else is the same: feeding, mulching, pruning.
Step 1: Watering Rhododendrons
Rhododendron is a moisture-loving plant, so throughout the growing season, you should monitor the level of soil moisture. Do not forget about it after flowering, especially if the weather is dry. This is because rhododendrons develop their flower buds in August and September and the lack of moisture can have a negative effect on flowering in the coming season.
In the absence of rain, water the bushes about once every 3-4 days, pouring 1-1.5 buckets under each adult plant. Water very carefully so as not to erode the soil and not to expose the rhododendron roots, which are close to the soil surface.
Despite its need for moisture, rhododendrons tolerate stagnant water very poorly. For this reason, take care of a good drainage area, where rhododendron will grow, even at the planting stage. This is especially important in areas with a high water table. With frequent and heavy rains, make ditches around the bush for the outflow of water.
In late autumn, when the temperature drops below 2°C, give rhododendrons a watering. To prepare well for winter, the plant should get as much moisture as possible. To do this, pour at least 3-4 buckets of water under each adult bush. After such a “recharge” rhododendron will be easier to endure severe frosts. If the autumn was rainy and the soil in the flower bed is damp to a depth greater than a spade’s bayonet, this procedure is not necessary.
Not only evergreens but also deciduous rhododendrons need watering, but the evergreen varieties can also be watered by sprinkling so that they get the moisture they need more quickly.
Step 2: Pruning rhododendrons in autumn
Nature has endowed rhododendrons with a beautiful crown, so many people think that they do not need pruning. However, this is not entirely true. How to prune rhododendrons?
First, immediately after flowering, all seed capsules are removed, so that the plant does not waste energy on the formation of seeds. They are snipped by hand or cut with secateurs.
Secondly, every few years, in the autumn, carry out rejuvenating pruning. During its performance, all old, unsightly growing, and bare branches are removed. During the same period, dried or broken shoots are also removed.
Step 3: Mulching
Mulching is one of the most important steps in preparing rhododendrons for winter. As mentioned above, rhododendrons have a shallow root system. A layer of mulch is needed to protect it in the winter from drying out in the frozen ground. In addition, under such a cover, the roots will not freeze even in the most severe frosts.
However, not all mulch is good for rhododendrons – lovers of acidic soil. What is the best mulch for rhododendrons:
- peat – take upland peat, because it has a higher level of acidity;
- Coniferous foliage – fallen needles are good, not green needles;
- coniferous bark – most commonly used pine, if no bark, you can take the sawdust of conifers.
Before you mulch the soil, remove all debris and weeds from the bedding circle. Fallen leaves of the rhododendron itself do not need to be removed: lay a layer of mulch directly on them. Under small bushes, the height of the mulching layer should be at least 4-5 cm, for tall rhododendrons – at least 10 cm. The mulch should be occupied by the entire root circle of the bush, but it makes no sense to put it near the trunks since all the roots are located further away.
Step 4: Autumn rhododendron nutrition
If summer is over and your rhododendrons still don’t have flower buds formed, you need to look for the cause and fix the situation right away. The reason for the lack of flower buds in rhododendrons can be due to improper fertilization. If you applied a large amount of nitrogen fertilizer, the bush will continue to grow and will not begin to prepare for winter.
How to stimulate the formation of flower buds in rhododendron? A phosphorus-potassium fertilizer, such as potassium monophosphate, will help you. Dilute 1 tbsp. of fertilizer in 10 liters of water and pour it directly on the mulching layer of the bushes. The nitrogen-free fertilizer will stop the rhododendrons from growing in green mass, and they will put all their energy into “the right direction”: the formation of flower buds and increased growth of the root system will begin.
Step 5: Covering Rhododendrons
The last step in preparing rhododendrons for winter is to create a cover. Is it necessary to cover rhododendrons for the winter, because most varieties can withstand frosts up to -30 ° C?
It is necessary to cover young bushes, which are not yet 4 years old: their roots may not be able to withstand severe frosts.
Evergreen rhododendrons are also covered because they are not as winter-hardy as the deciduous varieties, which can survive the winter without protection.
Moreover, rhododendrons need cover not only to protect themselves from frost. They can also suffer a lot from the bright February or March sun and strong winter winds.
How to properly cover rhododendrons for the winter?
Only use breathing materials such as lutrasil, spunbond, burlap, etc. for covering. The use of film is not recommended, because often inside the film cover condensate forms, which leads to increased humidity and negatively affects the development of shrubs.
In snowy winters, large amounts of fallen snow can cause the rhododendron to break off the woody shoots. To avoid this, make shelter in the form of a pyramid or cone. To do this, place supports (e.g. wooden stakes or metal pins) around the shrub and then connect them at the top. Tie-down the sprawling rhododendron branches with twine so that they do not touch the cold walls of the shelter.
Wrap the frame with covering material and tie it with rope. Such a cover will protect the rhododendron from heavy snowfall and winds, and from bright sunlight, which can cause burns on the leaves.
Only begin covering rhododendrons when temperatures fall below -8 to -10°C. Covering too early can harm the shrubs because they will begin to wither, which can eventually lead to the rotting of the plants.
If your rhododendrons grow in a secluded area and only need to be shielded from the bright sun, cover can be made in the form of a protective screen. Stretch a light-colored cloth over a wooden or metal frame and place the screen near the shrubs on the sunny side. Be sure to take care that the wind will not topple the protection on the plants. Such a screen can be installed not in the fall, but in late winter when the plants begin to need shading.
To properly prepare rhododendrons for winter, you need to start the work now, while there is still nothing to remind you of the cold weather.