Although the soil may seem moist, the shallow root system of rhododendrons cannot always absorb water in winter. This happens especially when the ground freezes. DLarge, evergreen leaves evaporate water all year round and must have constant access to it. The combination of frost, winter sun and wind leads to the so-called “physiological drought”, when the plant loses moisture faster than it can replenish it.
How to deal with this? First of all, water the rhododendron abundantly before winter. Water will get deep into the ground and the plant will be able to draw from these reserves. Also make sure to mulch the rhododendron. The protective layer will not only protect the roots against frost, but will also maintain moisture in the soil. When you see that the bush withers during frost, wait until the thaw before watering. Water poured during negative temperatures will turn the soil around the plant into a hard lump.
Rhododendrons require acidic, permeable soil with a pH of approximately 4.5-5.5. In too alkaline soil, the plant has trouble absorbing nutrients and weakens quickly. Neither watering nor fertilizing will help it then. The roots will not be able to absorb anything from an unsuitable substrate.
Instead of watering the rhododendron, check the pH of the soil in which it grows. It’s best to do this using testers that you can find in every store. If it turns out that the soil has a pH above 6, it needs to be acidified. Use acidic peat or acidifying fertilizers for this purpose. It will also help to mulch the ground with coniferous wood chips or needles, which acidify the soil.
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Pay attention to the place where the rhododendron grows. Rhododendrons like slightly shaded positions and sheltered from the wind. This helps them slow down the processes of water evaporation through the leaves, which is also helped by rolling the leaves. If your plant is growing as a solitaire in full sun, it may not cope. During frosts, take care not only of the roots, but also of the leaves, especially in young bushes.
It is best to prepare covers that will protect the plant against wind, frost and sun. Agrotextile or straw is suitable for this purpose. The material should not only protect, but also allow air to pass through. Remember to uncover the rhododendron during the thaw and remove the covers completely in spring.
