Rhododendron is one of the ornamental shrubs with the most beautiful flowers. With proper care, it pleases the eye with its large filigree flowers all spring. It is very important, first of all, to provide the plant with regular fertilizing. In this regard, the amateur gardener should pay attention to a few things. We explain how to fertilize the rhododendron, what home remedies come into question and how to improve the soil.
Table of contents
- Fertilize rhododendron: Supply the plants with important nutrients in spring
- Fertilize the rhododendron properly: Horn shavings improve the soil without changing its pH value
- Fertilizer with iron against lime in the soil: Fertilize the rhododendron with coffee grounds
- Fertilizer from horse manure
- Fertilize rhododendron: Yellow leaves are a sign of iron deficiency
- Vinegar against weeds and pests
Fertilizing rhododendrons: Provide plants with important nutrients in spring
Rhododendron is usually fertilized in the spring. Fertilizing in the fall makes the woody plant more susceptible to frost, so it is not recommended. March is the right time to improve the soil with a suitable fertilizer. Especially the young plants need a lot of nutrients to form their root system and grow quickly. The rule of thumb is that you should work slow-release fertilizers into the soil as early as March, and liquid fertilizers – in April. Depending on the needs and soil composition, you can fertilize the woody plant a second time in the summer.
However, to find the right fertilizer is not easy. Since the rhododendron is very sensitive to lime , the fertilizer should have a neutral to slightly acidic pH. Suitable fertilizers are for example:
- Coffee grounds – fertilize once at the start of the gardening season.
- Needle compost – fertilize every three weeks
- Horn shavings – fertilize the rhododendron every two weeks
- Horse manure – spread on the soil every two weeks
- Blue grain – use every two to three weeks
- Vinegar – use only when necessary, heavily diluted, no more than once a year
Fertilize the rhododendron properly: Horn shavings improve the soil without changing its pH value
Horn shavings are made from the claws and horns of barks. Horn shavings are rich mainly in nitrogen, but contain very little phosphate, potassium and other useful building materials. If the soil in your own garden is humus, then you can fertilize the rhododendron only with horn shavings. Just distribute them around the roots, which mostly grow superficially. However, if it is lean, then you can add the horn shavings to the fertilizer. For example, compost, which contains important nutrients, is well suited. The most suitable compost is made from bark or leaves, without the addition of lime.
Fertilizer with iron against lime in the soil: Fertilize the rhododendron with coffee grounds
The coffee grounds offer several advantages over the iron fertilizer from the garden center: It is a natural fertilizer and does not contain pollutants. It can also lower the pH of the soil and help against lime in the soil. Since the rhododendron is very sensitive to lime and in the worst case can even die, you should water the plant with lime-free water and regularly check the soil composition in the laboratory. It is best to do this at the start of the gardening season. Along with the lab results, you will also get recommendations regarding fertilizer. If they include iron fertilizer, then you can take coffee grounds and work them directly into the root zone.
Fertilizer from horse manure
Mature horse manure is perhaps the perfect fertilizer for rhododendron. It smells much less than cow manure and provides the soil with all the essential nutrients. Spread horse manure around the plant every two weeks. You can start doing this in March. You can stop fertilizing in mid-May.
Fertilize rhododendrons: Yellow leaves are a sign of iron deficiency.
Too much lime in the soil prevents the rhododendron from absorbing iron. The deficiency is noticeable by yellow leaves. But what should you do if the rhododendron leaves turn yellow? The first thing you should do is measure the pH of the soil. If it is above 8.5, then only one thing will help: replace the soil. It is best to buy substrate for rhododendron and mix in blue grain. If the pH is between 7 and 8.5, then you can save yourself the tedious and expensive replacement and instead dilute vinegar with water and water the plant with the solution. However, this home remedy kills all the microorganisms in the soil that decompose the substances and are very important for the plants. Therefore, in the next few days you should provide the soil with natural fertilizer. The most suitable is the home-made needle compost.
Vinegar against weeds and pests
By the way, vinegar also helps with a pest infestation and against weeds . In the case of weeds, simply pour the vinegar solution directly on the plants. After two weeks, you can repeat the procedure. Then be sure to fertilize the rhododendron.
However, you should use vinegar only if it is highly diluted. Otherwise, it could burn the roots of the rhododendron.