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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 frost-resistant shrubs do not require the same careful winter shelter 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 without pain.
Features of caring for rhododendrons in autumn
These small shrubs and trees with evergreen or winter-falling foliage belong to the Ericaceae family. They bloom in late spring or early summer. Deciduous rhododendrons have soft, light green leaves that change to beautiful red-orange tones in the fall. Evergreen varieties do not change color and remain green all year round. In winter they look exotic.
Like all other garden plants, rhododendrons require careful attention in the fall. Caring for evergreen and deciduous specimens does not differ significantly, but the latter are less capricious. Preparatory autumn work includes the construction of a shelter for rhododendrons for the winter.
Autumn care tips:
- The bushes are fed with preparations containing phosphorus and potassium, without nitrogen, to stop the growth of new shoots.
- It is recommended to add magnesium and sulfur from microelements.
- To prevent 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 the temperature drops to 0 °C. At above-zero temperatures, you cannot prune plants; intensive shoot growth will begin.
Many gardeners consider rhododendrons to be pampered plants, but this is not the case. Now there are many varieties that tolerate frost well; flower buds laid in the fall do not freeze even at -30 °C.
How to plant rhododendron in autumn
When purchasing a seedling at a garden center, among the zoned varieties, preference is given to the most frost-resistant ones. Their successful wintering and the success of further cultivation depend on proper planting and care of rhododendrons in the fall. You cannot buy seedlings with immature, green shoots. A strong bush that overwinters well has woody shoots and growth buds at the top.
Frost-resistant evergreen varieties.
Helsinki University - a compact bush, abundantly strewn with large pink flowers at the end of May.
Nova Zembla - a variety with bright red simple flowers.
Keninghams White - a 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, for example, Japanese and Daurian, overwinter without shelter.
Landing dates
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 the 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. It is better not to plant heat-loving varieties in the fall; they may not survive the winter.
Preparing the landing site
To successfully grow rhododendrons, it is important to choose the right place for planting and prepare it. These plants do not have the same suction roots as most ornamental shrubs. The thin roots contain mycorrhiza, which helps the shrubs feed and grow. Therefore, a special soil is needed - loose and acidic.
Evergreen varieties are planted in light partial shade or so that they are covered on the south side by tall buildings, fences, and decorative conifers. Deciduous varieties can be planted in more open, sunlit areas protected from the wind.
A planting hole with acidic soil is prepared for rhododendrons. The following components are taken for the soil mixture:
- peat – 2 hours;
- vermicompost or leaf humus – 1 hour;
- pine litter – 1 tsp.
For planting rhododendrons, only high-moor, acidic peat can be used.It should be coarse-fiber with a low degree of decomposition. A hole is made with a depth of at least 40 cm and a diameter of 50-60 cm. Then it is filled with 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 a lump of earth 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 cannot plant shrubs close to plants that have a superficial root system - birch, willow. They will take away moisture and nutrients.
- Rhododendron grows well in rows with apple, pear, pine, larch, and spruce.
- If there is groundwater close to the surface in the area, it is advisable to place granite gravel drainage at the bottom of the hole, which does not produce a lime reaction. It will protect the roots from stagnation of 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 collar at soil level. When planted in depth, the plant will rot, and in a raised state it will experience a lack of moisture. This will all affect the next winter.
To prevent a large rhododendron from being blown over by the wind, a support is installed nearby. The trunk is tied to a support peg with synthetic twine. After planting, the seedling is well watered. Mulching the tree trunk circle will help prepare the rhododendron for winter. Heather compost or acidic high-moor peat is used as mulch, which will serve the shrubs as an additional source of nutrients when the ground thaws in the spring.
Transplanting rhododendron to another place in the fall
If the plant does not bloom, grows poorly or begins to wither, you can replant it in the fall by renewing the soil in the old hole or choosing a new place. A transplant may be necessary due to an unsuccessfully chosen location, where cold winds blow or the water comes close to the surface. Sometimes a variety is so beautiful that you want to plant the plant closer to the front entrance of the house.
The plant has a shallow, fibrous root system, making it easy to dig up. It is better to carry out the work 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 pine litter.
- Dig around the bush around the perimeter of the crown with a sharp shovel.
- Lift by supporting the trunk.
- Lightly clear the soil from the roots.
- Transplant the bush to a new location so that the root collar remains at soil level.
- Water and mulch the tree trunk circle.
After transplanting rhododendron in the fall, preventive spraying is done with copper-containing preparations. In green shrubs, the leaves are treated not only superficially, but also from the inside. In winter, the tree trunk circle is mulched with pine litter or acidic high-moor peat.
How to care for rhododendron in autumn
The autumn set of activities for growing different types of rhododendrons is similar. While it’s warm, you can carry out the final fertilizing, plant young seedlings or transplant adult bushes to a new place where they will look more advantageous. Closer to mid-autumn, when deciduous varieties begin to fly away and the approach of cold weather becomes more noticeable, pruning and water-replenishing watering are carried out, and the tree trunk circle is mulched. In November, ripe seeds are collected for growing seedlings.For heat-loving varieties, frames are prepared from flexible pipes or wooden beams. Cover the bushes selectively, only with the onset of stable cold weather.
In autumn, deciduous rhododendrons' leaves turn yellow. Under the bright autumn sun, they acquire a golden yellow, orange or red color, which looks no less beautiful than spring blooms. Evergreen rhododendrons slightly lose leaf turgor in preparation for colder weather, but do not change their green color. Fallen leaves are not removed from healthy bushes in the fall. It will serve as additional nutrition for the plants. Mulch is poured on top of the leaf litter along the entire tree trunk circle.
Watering rhododendrons in autumn
Rhododendrons are very demanding when it comes to watering. They should not be overwatered or dried out. During the growing season, monitor the humidity of the tree trunk circle, make drainage grooves for excess moisture, and mulch the soil so that it does not dry out.
Moisture-recharging watering of evergreen and deciduous rhododendrons is a mandatory autumn event. Each plant cell must be saturated with moisture, this will protect it from freezing in winter. At least 30-40 liters of water are poured under each bush up to 1 m high.
They begin water-recharging watering of rhododendrons when the air temperature drops to +2 °C and the leaves begin to fall.
Top dressing
At the end of summer and beginning of autumn, rhododendrons are fed with potassium monophosphate so that they lay flower buds for the next year. Fertilizer will help the shoots that grow back after flowering to mature before frost. Fertilizing is applied when the soil temperature is above +10 °C.
Potassium monophosphate (1 tbsp.without top for 10 liters of water) it is better to apply under the plants in the evening, watering along the edge of the bush. For 1 sq. m area consume a bucket of solution. The leaves can be treated with rhododendron fertilizer with microelements - "Uniflor", which will additionally protect the plants from fungal infections.
Trimming
In order for rhododendrons to bloom profusely, you need to rejuvenate adult bushes by pruning. This is done approximately 10 days after applying fertilizer to the soil, before frost occurs. Depending on the region, the fall event falls at the end of September or mid-October. In the fall, sanitary pruning is also carried out, removing diseased and broken branches that can become a source of disease. The cut areas are covered with Rannet paste.
How to preserve rhododendrons in winter
The gardener’s task is to help rhododendrons survive wintering in the open ground with minimal losses. These plants are very hardy and young, newly planted specimens or heat-loving varieties can freeze.
To make it easier for rhododendrons to endure winter, it is advisable to plant plants in groups. Heather, hydrangea, and conifers, which love acidic soil, can grow nearby. When the air temperature drops to -4 °C, the leaves of evergreen rhododendrons will curl into tubes. So, they prepare for winter by closing the stomata on the underside of the leaf blades, through which moisture evaporates.
Rhododendrons are afraid of frost only by cold winds and the bright February sun. At the end of winter, when the sun begins to shine more intensely, the curled leaves begin to evaporate moisture, and the roots from the frozen ground cannot compensate for its lack. At this time, it is advisable to shade the plants.
Should I cover rhododendron for the winter?
To decide whether rhododendron needs shelter in winter, you need to know in which frost resistance zone it can be grown. Deciduous shrubs tolerate winters in temperate climates 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 bush when the air temperature is -10 °C, otherwise the shoots will smear. Before this, preparation is carried out:
- feeding;
- watering;
- fungicide treatment;
- mulching tree trunk circles;
- 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. You should 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 with pine litter for the winter, securing it on top with spruce branches. And when snow falls, throw a snowdrift on top - under a blanket of snow 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 hill up the tree trunk to protect the plants from frost.The layer of mulch depends on the height of the bush. For rhododendron up to 1 m high, a layer of mulch of 4-5 cm is sufficient. For large specimens, the soil is mulched to a height of 15-20 cm. For this, dry pine needles mixed with peat are used.
Burlap is suitable for covering the trunk and shoots from the winter sun, but film cannot be used; air must pass freely through the surface of the covering material. Burlap will protect plants from drying sunlight, wind and birds that love to feast on flower buds. Small deciduous rhododendrons can be covered with oak leaves before severe frosts.
Spruce spruce branches are suitable as insulation. It is better not to use hay and straw; mice like to live in them. Another way to protect against frost is to create a frame to shelter rhododendrons for the winter.
Frames for sheltering rhododendrons
Rhododendron bushes are spreading; 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 to the ground. The frame is installed in early autumn, when the ground is not yet frozen. With the onset of cold weather, protective material is pulled on top in 1-2 layers.
The size of the frame base depends on the diameter of the crown and the height of the bush. The gap between the covering material and the shoots should be about 15 cm, since plant tissue freezes in places of close contact.
The arches 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 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 scorching sun. You can make a simple and reliable shelter for a rhododendron with your own hands from three poles, burying them around the bush and tying them at the top in the shape of a wigwam. And put covering material on top.
How does rhododendron endure winter?
Rhododendrons overwinter well under cover. Even young seedlings planted in open ground the day before autumn are not damaged by frost. This is provided that the planting material is of high quality and the planting is correct.
Bushes that have formed flower buds, carefully covered before the onset of severe frosts, will definitely bloom. In 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 tree trunk with warm water to help the plants absorb moisture after a long winter. Rhododendrons, which overwinter under cover, open when the daffodils and tulips bloom. It is advisable to do this in cloudy weather. Shrunken, diseased shoots are cut back to healthy tissue, and all bushes are treated with fungicides.
If, after removing the cover, the leaves of the evergreen rhododendron did not straighten out, but remained in a curled position, it means that it lost a lot of moisture in winter. The plant begins to be sprayed and watered daily until it straightens its leaves. To make the ground under the bush warm up faster, rake out the mulch and water it with water with the addition of growth stimulants (dilute one ampoule of Zircon or two ampoules of Epin per 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.The flowering does not last long, but it is so beautiful that it is worth all the work invested throughout the year. When growing these plants, everyone is afraid of winter. In fact, frosts are not so bad. The death of rhododendrons can only be caused by inattention, mistakes made when choosing a variety, incorrect autumn planting or preparation for winter.
