The rhododendron blossom makes the gardener's heart beat faster. However, it needs to be properly cared for and protected from diseases to bloom lushly.
Rhododendrons (Rhododendron) are one of the largest genera within the heath family (Ericaceae). With more than 1000 species worldwide, the rhododendron is geographically represented almost everywhere. It is therefore not surprising that it can be attacked by a large number of pests and diseases. We provide tips on proper care and effective pest and disease control so your rhododendron can continue to bloom in all its glory.
Caring for Rhododendrons
The rhododendron is relatively easy to care for. However, at certain times of the year he wants some attention from you. We reveal what you should pay attention to when it comes to proper care. Before we get started, however, it should be said that certain points should be considered when planting the rhododendron. Rhododendrons like slightly acidic soil and hate waterlogging. However, many soils, especially in southern Germany, tend to be neutral to slightly basic. It can therefore be advantageous to dig a large planting hole and fill it with a special rhododendron soil.
Watering rhododendrons correctly
Especially when the rhododendron plants are small, they want to be watered regularly. However, no waterlogging should occur, as the rhododendron, as a shallow-rooted shrub, is very sensitive to this. The larger and older the rhododendron gets, the less often it needs to be watered, as the roots are now more developed. Signs of the need for watering can be hanging flower buds during flowering or curling leaves.
Note: Water your darling at longer intervals, but then with a little more water. Especially during dry periods, too small amounts of water can evaporate quickly before they penetrate the soil.
Fertilize Rhododendron
The rhododendron is especially happy about onelong-term fertilization. The best time for this is in spring, which means shortly after planting freshly planted shrubs. Work the fertilizer into the root area so that the nutrients can be better absorbed into the soil. Also mix horn shavings, compost and/or coffee grounds with the excavated soil during the planting process and then put it back in the planting hole. These fertilizers are all purely organic, some have slightly acidic properties for the soil and have a positive effect on soil life. While coffee grounds increasingly lower the soil pH value, but are not a very large supplier of nutrients, the compost takes on the task of providing nutrients over the long term. Horn shavings (or horn meal) do not affect the soil pH, but also provide a long-term nutrient release with a high nitrogen content. If you prefer to fertilize regularly than to use long-term fertilizers, stop fertilizing from October to start the dormant phase.
For your darlings that have already taken their place in the garden for a long time, the expert recommends giving the shrub an energy boost a few weeks before flowering with a mixture of mineral and organic fertilizer. You can find out more about this in the video.
In addition to the home remedies mentioned above, there are also special rhododendron fertilizers on the market that cover the entire spectrum of nutrients and also (sometimes fully organic) provide additional nutrients in the medium term. A primarily organic organic fertilizer such as our Plantura organic hydrangea fertilizer is also suitable for rhododendrons. The long-term fertilizer releases its nutrients gently and over a longer period of time to the rhododendron and also provides it with iron.
Note: Under special circumstances, a second fertilization can also be carried out in summer. However, this is only necessary if a nutrient deficiency manifests itself in the form of yellow and wilted leaves.
You can find more about the correct fertilization of your rhododendron here.
Pruning Rhododendron
The rhododendron basically does not need any special pruning to bloom profusely. With increasing age, however, there is also increased lignification of the shoots, which is why a rejuvenation cut makes sense if necessary. A radical rejuvenation pruning should be carried out before flowering, as this way you do not unnecessarily waste the energy reserves of your rhododendron and nesting birdsbe disturbed.
Use sharp rose scissors to cut off old shoots so that the bare interior of the bush gets light again. It is important to ensure that you cut the shoots at an angle. In this way, no dew or rainwater collects on the open areas of the shoots, which could allow diseases to penetrate. If you don't want to start with a radical rejuvenation cut, but only want to preserve the shape of your rhododendron, you can carry out a comprehensive maintenance cut immediately after flowering. Unattractive, diseased and injured shoots are removed here until you are satisfied with the growth form of your favorite.
We have put together more tips and tricks for pruning your rhododendrons here for you.
Caring for rhododendrons after flowering: bursting out flowers
After you've done a thorough pruning, you can still do something good for your rhododendron. To do this, simply break off all the wilted flowers on the remaining shoots. This promotes the formation of buds in the next year and eliminates spore foci, which prevents infestation by fungal pathogens.
Transplanting rhododendrons
You may need to transplant your rhododendron. We have summarized the best way to do this in a special article.
Rhododendron Diseases
The rhododendron genus is particularly susceptible to fungal diseases, but animal pathogens are also up to mischief in the evergreen foliage of the rhododendron.
Rhododendron has yellow and brown leaves
The discolouration of the leaves usually has two causes: either the plant was cared for incorrectly or it was attacked by a fungus. In order to do something about the discoloration, the source of the damage must first be identified. Chlorosis caused by improper care can either be caused by soil that is too calcareous or by a lack of nitrogen. Depending on the pathogen, different yellow or brown lesions form in fungal infections.
Here you will find a list of common fungal diseases of rhododendrons, as well as all diseases that can occur due to animal pathogens.
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