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Caring for rhododendrons in the fall and preparing for winter will help preserve heat-loving varieties and young seedlings for spring flowering. Mature hardy shrubs do not require the same thorough cover in winter as roses, but they bloom no less beautifully. It is useful for every gardener to know what autumn activities will help rhododendrons survive the harsh cold painlessly.
Features of caring for rhododendrons in the fall
These small shrubs and trees with evergreen or winter foliage belong to the Heather family. They bloom in late spring or early summer. Deciduous rhododendrons have soft, light green leaves that change to beautiful red-orange tones in autumn. Evergreen varieties do not change color, are green all year round. In winter they look exotic.
Like all other plants in the garden, autumn rhododendrons require careful attention. Care for evergreen and deciduous specimens does not have significant differences, but the latter are less capricious. The preparatory autumn work includes the construction of a shelter for rhododendrons for the winter.
Fall Care Tips:
- Shrubs are fed with preparations with phosphorus and potassium, without nitrogen, to stop the growth of new shoots.
- Of the trace elements, it is recommended to add magnesium and sulfur.
- For the prevention of diseases, it is necessary to treat shrubs with fungicides and insecticides.
- Abundant autumn watering and mulching will protect rhododendrons from winter frosts.
- Autumn pruning is possible when it gets colder to 0 ° C. At positive temperatures, it is impossible to prune plants; intensive growth of shoots will begin.
Many flower growers consider rhododendrons to be pampered plants, but this is not so. Now there are many varieties that tolerate frost perfectly, flower buds planted since autumn do not freeze even at -30 ° C.
How to plant rhododendron in autumn
When buying a seedling in a garden center, among the zoned varieties, the most frost-resistant ones are preferred. From the correct planting and care of rhododendrons in the fall depends on their safe wintering and the success of further cultivation. You can not buy seedlings with unripened, green shoots. A strong bush that will winter well has lignified shoots, growth buds are laid at the top.
Frost resistant evergreen varieties.
Helsinki University – a compact bush, abundantly strewn with large pink flowers at the end of May.
New Zembla – a variety with bright red simple flowers.
Keninghams White – shrub with delicate white inflorescences.
Green leaves can burn from bright sunlight in winter, so shelters are needed from the end of January. Deciduous rhododendrons, such as Japanese and Dahurian, winter without shelter.
Terms of planting
It is advisable to plant rhododendrons in open ground in the fall and provide care a month before the onset of frost so that they have time to adapt and take root in warm soil. The last date for planting depends on the region: in the south it is October, in the Urals and Siberia it is September. Cultures of heat-loving varieties are best not planted in the fall, they may not overwinter.
Site preparation
For the successful cultivation of rhododendrons, it is important to choose the right place for planting and prepare it. These plants do not have such suction roots as most ornamental shrubs. Thin roots contain mycorrhiza, which helps the shrubs to feed and grow. Therefore, the soil needs a special one – loose and acidic.
Evergreen varieties are planted in light partial shade or so that tall buildings, fences, and decorative conifers cover them on the south side. Deciduous varieties can be planted in more open, sunlit areas protected from the wind.
A planting pit with acidic soil is prepared for rhododendrons. For the soil mixture take the following components:
- peat – 2 hours;
- biohumus or leaf humus – 1 hour;
- pine litter – 1 tsp.
For planting rhododendrons, you can use only riding, sour peat. It should be coarse fiber with a low degree of decomposition. The pit is made at least 40 cm deep and 50-60 cm in diameter. Then it is filled with the prepared soil mixture.
Rules for planting rhododendron in open ground in autumn
Before planting, the seedling is removed from the container and immersed, together with an earthen clod, in a bucket of water. Leave in this state for 20-30 minutes until the roots of the plant are saturated with moisture.
Tips for planting rhododendron in the fall:
- You can not plant a shrub near plants with superficial root systems – birch, willow. They will take away moisture and nutrients.
- The rhododendron grows well in rows with apple, pear, pine, larch, spruce.
- If there is groundwater in the area close to the surface, it is advisable to put drainage from granite gravel at the bottom of the pit, which does not give a lime reaction. It will keep the roots from stagnant moisture.
- To quickly create a beautiful bush, you can plant 2-3 seedlings in one large hole, placing them at a distance of about 50 cm from each other.
A soaked seedling is placed in the prepared hole. Check the position of the root neck at the level of the soil. With a deep planting, the plant will rot, and in an elevated state, it will experience a lack of moisture. All this will affect the future wintering.
To prevent a large rhododendron from being overwhelmed by the wind, a support is installed nearby. The trunk is tied to the support peg with synthetic twine. After planting, the seedling is well watered. Mulching the trunk circle will help prepare the rhododendron for winter. Heather compost or acidic peat moss is used as mulch, which will serve as an additional source of nutrients for the shrub when the ground thaws in spring.
Transplanting rhododendron in the fall to another place
If the plant does not bloom, grows poorly or begins to wither, in the fall you can transplant it by updating the soil in the old pit or choosing a new place. A transplant may be needed due to an unsuccessfully chosen place where cold winds blow or water comes close to the surface. Sometimes the variety is so beautiful that you want to plant a plant closer to the front door of the house.
The plant has a shallow, fibrous root system, making it easy to dig. Work is best done in September so that the rhododendron has time to take root. Transfer order:
- In the new pit, acidic soil is prepared from high-moor peat and coniferous litter.
- They dig a bush around the perimeter of the crown with a sharp shovel.
- Raise by supporting the trunk.
- Lightly scrape the soil off the roots.
- The bush is transplanted to a new place so that the root neck remains at the level of the soil.
- Water and mulch the near-trunk circle.
After rhododendron transplantation, preventive spraying with copper-containing preparations is done in the fall. In green shrubs, the leaves are processed not only superficially, but also from the inside. For the winter, the near-stem circle is mulched with pine litter or acidic high-moor peat.
How to care for rhododendrons in autumn
The autumn set of measures for growing various types of rhododendrons is similar. While it is warm, you can carry out the last top dressing, plant young seedlings or transplant adult bushes to a new place where they will look more advantageous. Toward the middle of autumn, when deciduous varieties begin to fly around, and the approach of cold weather becomes more noticeable, pruning and water-charging watering are carried out, and the near-stem circle is mulched. In November, ripened seeds are harvested for growing seedlings. For heat-loving varieties, frames are prepared from flexible pipes or wooden beams. Bushes are covered selectively, only with the onset of stable cold weather.
In autumn, deciduous rhododendrons turn yellow leaves. Under the bright autumn sun, they turn golden yellow, orange or red, which looks no less beautiful than spring flowering. Evergreen rhododendrons slightly lose leaf turgor, preparing for a cold snap, but do not change their green color. Fallen leaves are not removed in autumn from under healthy bushes. It will serve as additional nutrition for plants. Mulch is poured over the leaf litter around the entire trunk circle.
Watering rhododendrons in autumn
Rhododendrons are very demanding on watering. They can not be poured and dried. During the growing season, they monitor the humidity of the near-stem circle, make drainage grooves for excess moisture, and mulch the soil so that it does not dry out.
Moisture-charging watering of evergreen and deciduous rhododendrons is a mandatory autumn event. Each cell of plants should be saturated with moisture, this will prevent freezing in winter. At least 1-30 liters of water are poured under each bush up to 40 m high.
Moisture-charging watering of rhododendrons begins, when the air temperature drops to +2 ° C, the leaves begin to fall off.
Additional fertilizing
In late summer and early autumn, rhododendrons are fed with potassium monophosphate so that they lay flower buds for next year. Fertilizer will help ripen shoots that have grown after flowering, before frost. Top dressing is applied when the soil temperature is above +10 ° C.
Potassium monophosphate (1 tablespoon without top per 10 liters of water) is best applied under plants in the evening, watering along the edge of the bush. For 1 sq. m area spend a bucket of solution. On the leaves, you can treat rhododendrons with fertilizer with microelements – “Uniflor”, which will additionally protect plants from fungal infections.
Trimming
In order for rhododendrons to bloom profusely, you need to rejuvenate adult bushes with pruning. Do this about 10 days after fertilizing the soil, before the onset of frost. Depending on the region, the autumn event falls at the end of September or mid-October. Sanitary pruning is also carried out in autumn, removing diseased and broken branches that can become a source of disease. Places of cuts are covered with Rannet paste.
How to save rhododendrons in winter
The task of the gardener is to help rhododendrons survive the winter in the open field with minimal losses. These plants are very hardy and young, just planted specimens or heat-loving varieties can freeze out.
To make it easier for rhododendrons to endure winter, it is advisable to plant plants in groups. Heather, hydrangea, conifers, which love acidic soil, can grow nearby. When the air temperature drops to -4 ° C, the leaves of evergreen rhododendrons will curl into tubules. So, they prepare for winter by closing the stomata on the underside of the leaf blades through which moisture evaporates.
More than frost, rhododendrons are afraid only of cold winds and the February bright sun. At the end of winter, when the sun begins to shine more intensely, the twisted leaves begin to evaporate moisture, and the roots from the frozen ground cannot make up for it. At this time, it is desirable to shade the plants.
Should I cover the rhododendron for the winter
To decide whether a rhododendron needs shelter in winter, you need to know in which hardiness zone it can be grown. Deciduous shrubs tolerate temperate winters more easily. In nature, some species of rhododendrons grow in Kamchatka and Siberia, where it is cold in winter. Hybrid evergreen varieties are less frost-resistant, so seedlings are covered in the first 3 years after transplanting into open ground.
When to cover rhododendrons for the winter
The shelter is fixed on a support around the shrub when the air temperature is -10 ° C, otherwise the shoots will sprout. Prior to this, preparations are being made for:
- top dressing;
- watering;
- fungicide treatment;
- mulching of tree trunks;
- installation of frames over groups of rhododendrons or separately growing bushes.
When frosts begin, cover the bushes over the frame with spunbond or lutrasil. On warm days, raise the edges of the covering material to a small height from the ground on both sides of the shelter to ventilate the plants.
How to cover rhododendrons for the winter
Even adult rhododendrons need shelter from the wind. Do not make it too dense, as for roses, shrubs are prone to rotting. The choice of type of shelter depends on the size of the plant. A small rhododendron can be covered for the winter with pine litter, fixing it on top with spruce branches. And when the snow falls, throw a snowdrift on top – under the snow blanket, the plant is not afraid of frost.
The root system of rhododendrons is located close to the surface, in the fall it is necessary to spud the near-stem circle to protect the plants from frost. The layer of mulch depends on the height of the shrub. For a rhododendron up to 1 m high, a layer of mulch of 4-5 cm is enough. In large specimens, the soil is mulched to a height of up to 15-20 cm. For this, dry pine needles mixed with peat are used.
Burlap is suitable for sheltering the trunk and shoots from the winter sun, but the film cannot be used; air must pass freely through the surface of the covering material. The burlap will protect plants from the withering sun rays, wind and birds that love to feast on flower buds. Small deciduous rhododendrons can be covered with oak leaves before severe frosts.
Spruce branches are suitable as a heater. It is better not to use hay and straw, mice like to settle in them. Another way to protect against frost is to create a frame for sheltering rhododendrons for the winter.
Frames for sheltering rhododendrons
Rhododendron bushes are sprawling, when a lot of snow falls on top of the shelter, it will break the branches, so it is advisable to build a rigid frame. The shape of the frame base should be pyramidal so that the snow rolls down to the ground. The frame is installed in early autumn, when the ground has not yet frozen. With the onset of cold weather, a protective material is pulled from above in 1-2 layers.
The size of the frame base depends on the diameter of the crown and the height of the shrub. The gap between the covering material and the shoots should be about 15 cm, since in places of close contact, freezing of plant tissues occurs.
Arcs are usually installed at a distance of 35 cm from each other. To strengthen the covering material on the frame, it is tied at the bottom with a rope or pressed down to the ground with bricks. Near the bush, you can simply drive in a high support and throw covering material on top to protect the shoots from snow and the scorching sun. You can make a simple and reliable shelter for a rhododendron with your own hands from three poles, burying them around a bush, and tying them at the top in the form of a wigwam. And put covering material on top.
How does rhododendron endure winter
Rhododendrons winter well under cover. Even young seedlings planted in open ground on the eve of autumn are not damaged by frost. This is provided that the planting material is of high quality and the fit is correct.
Carefully sheltered before the onset of severe frosts, the bushes that laid flower buds will definitely bloom. In the spring, you should not rush to open rhododendrons when the bright sun is shining, and the earth has not yet warmed up. In March, you can water the near-stem circle with warm water to help the plants absorb moisture after a long winter. Rhododendrons are opened, which hibernate under cover when daffodils and tulips bloom. It is advisable to do this in cloudy weather. Shrunken, diseased shoots are cut to healthy tissue, and all bushes are treated with fungicides.
If, after removing the shelter, the leaves of the evergreen rhododendron did not straighten out, but remained in a folded position, then it lost a lot of moisture in winter. The plant begins to be sprayed and watered daily until the moment when it spreads the leaves. In order for the earth under the bush to warm up faster, they rake off the mulch and water it with water with the addition of growth stimulants (one ampule of Zircon or two ampoules of Epin is diluted with 10 liters of water). Mulch the bush when the soil warms up well.
Conclusion
Caring for rhododendrons in the fall and preparing for winter will require a little time from the gardener. Flowering does not last long, but it is so beautiful that it is worth all the labor invested during the year. When growing these plants, everyone is afraid of winter. In fact, frosts are not so terrible. Only inattention, mistakes made when choosing a variety, improper autumn planting or preparation for winter can lead to the death of rhododendrons.
