Rhododendrons - the Greek name means something like "rose tree" - are popular ornamental trees in the garden. There is an almost unmanageable number of different cultivars that inspire with their lush flowers. Regular fertilization is essential so that you can fully enjoy the rhododendron blossom. You can read in our guide which rhododendron fertilizers are recommended and what you need to pay attention to.
Rhododendron fertilizer is precisely tailored to the needs of rhododendrons
Our recommendations
our recommendation
COMPO rhododendron long-term fertilizer for all types of morose plants, 3 months long-term effect, 850 g, 17m²
10.74 EUR To the product| quantity / packaging | 850 grams |
|---|---|
| fertilizer type | mineral |
| fertilizer form | solid, granules |
| NPK composition | 16+5,5+14 |
| ingredients | with 2 percent magnesium and other trace nutrients |
| price/kg | about {PRICE/0.85} EUR |
The COMPO rhododendron long-term fertilizer is not only suitable for rhododendrons, but for all types of ericaceous plants. With a share of 16 percent, it contains a lot of nitrogen, which is essential for healthy and vigorous growth. With a phosphorus content of 14 percent, flowering is also ensured that is as magnificent as it is long-lasting. Potassium and magnesium, in turn, strengthen the plants' defenses and are important for healthy foliage and strong green leaf color. Due to the three-month long-term effect, one fertilization per season is sufficient, which is ideally done right at the beginning of the budding. The nutrients are immediately available for the plants.
our recommendation
Dehner hydrangea and rhododendron fertilizer, 2 kg, for approx. 25 sqm
8.49 EUR To the product| quantity / packaging | 2 kilograms |
|---|---|
| fertilizer type | organic-mineral |
| fertilizer form | solid, granules |
| NPK composition | 10+4+7 |
| ingredients | 6 percent sulfur, 0.8 percent magnesium, earthworm humus, mycorrhiza |
| price/kg | about {PRICE/2} EUR |
The rhododendron and hydrangea fertilizer from Dehner not only impresses with its comparatively low price, but also with its mode of action. The fertilizer contains both organic and mineral ingredients. Some nutrients are immediately available for the plants, others develop their potency later. This results in an even supply of nutrients, and the rhododendron fertilizer also promotes soil life and thus natural soil fertility by adding earthworm humus and mycorrhiza fungi. The 2 kg pack is sufficient for approx. 25 square meters. Ideally, apply the fertilizer two to three times a year, the first time before flowering (end of March).
our recommendation
Oscorna Rhododendron Fertilizer 20kg
37.47 EUR To the product| quantity / packaging | 20 kilograms |
|---|---|
| fertilizer type | organic-mineral |
| fertilizer form | solid, granules |
| NPK composition | 6+3+0,5 |
| ingredients | 75% organic substances |
| price/kg | approx. EUR {PRICE/20} |
The rhododendron fertilizer from the manufacturer Oscorna is inexpensive, comes in a large package and no frills: just the right product if you have a lot of rhododendrons, hydrangeas and other ericaceous plants in your garden. This fertilizer is also suitable for azaleas, ericas and related plants cultivated in pots. The Oscorna rhododendron fertilizer consists of 75 percent organic components of both animal and plant origin, which ensure a natural long-term effect. In addition, they activate soil life and thus stimulate the natural formation of humus. In addition to the plants mentioned, the product is also suitable for supplying bilberries (blueberries).
Purchase Criteria
scope of application
Rhododendrons and the azaleas related to them are cultivated both outdoors in the garden, as a container plant on the balcony or terrace, and as a houseplant (especially Indian azalea, Rhododendron simsii). Depending on the form of cultivation, different rhododendron fertilizers are used. For example, for indoor azaleas, you should use fertilizers that are specially designed for flowering houseplants. Outdoor rhododendrons, on the other hand, can be supplied with rhododendron fertilizer in liquid or granular form, but you should prefer brands with a predominantly organic composition.
fertilizer form
solid fertilizer: Solid rhododendron fertilizers are available as easily dosed and almost dust-free granules, which are simply worked into the surface of the root area of the bushes and then watered vigorously.
liquid fertilizer: Liquid fertilizer, on the other hand, is a concentrate that must first be diluted with the irrigation water. Administering is very easy as all you have to do is water the plant with the enriched irrigation water.
fertilizer type
mineral fertilizer: Pure mineral fertilizers, some also refer to these types as synthetic fertilizers, are good for indoor plants. For garden plants, on the other hand, they are less recommended because they have a negative impact on soil health and thus humus formation. Their active ingredients are immediately available for the plants, but the agents are also overdosed very quickly and can then also have negative effects.
Organic Fertilizer: Organic fertilizers, on the other hand, consist of plant and/or animal matter (the latter often being slaughterhouse waste) that slowly decompose in the soil. In this way, the nutrients contained are gradually released to the plants. Organic fertilizers have a positive influence on soil life and thus on soil health, and over-fertilization is hardly possible. Only in the case of deficiency symptoms is no quick help possible due to the slow release of nutrients.
Mineral-organic fertilizer: Mineral-organic fertilizers combine the advantages of the first two forms, so that the plants have both fast and slow-acting nutrients available. The disadvantages of the other forms do not come into play here.
NPK composition
Rhododendrons have a high nutrient requirement and will bloom little or not at all if they are not adequately supplied. Rhododendron fertilizers should be high in nitrogen as this nutrient is essential for vigorous and healthy growth. Phosphorus ensures the long-lasting, magnificent flowering, but it should be contained in smaller amounts than nitrogen - a proportion of around four percent is ideal. Furthermore, potassium and magnesium should not be missing, as these are responsible for healthy foliage and also strengthen the immune system of the bushes.
long-term effect
If you do not want to fertilize regularly, it makes sense to use a rhododendron fertilizer with a long-term effect. These provide the plants - once fertilized - with all the necessary nutrients for four weeks, three or even six months, so that you only have to fertilize once, twice or three times a year. For all fertilizers with a long-term effect, the first dose is given in spring, before flowering. The month of April is ideal for this. A possible second fertilization can be done after flowering from the end of May.
PH value
Rhododendrons and other ericaceous plants need acidic soil. It is therefore important that the rhododendron fertilizer is free of any added lime and also keeps the pH at a constantly low level. Of course, the fertilizer itself should also have a correspondingly acidic pH value. This is usually printed on the packaging.
youtubefrequently asked Questions
When and how often should you fertilize rhododendrons?
Rhododendrons should be fertilized at least once a year, with the first fertilizing being done in April. Depending on the fertilizer used - and its long-term effect - fertilize a second time from the end of May. This gift should stabilize the plant after the exhausting flowering. If it has rained a lot, you can fertilize a third time from the beginning of July, but then only with half the recommended dose.
Is rhododendron fertilizer also suitable for other plant species?
Of course, rhododendron fertilizer is not only suitable for rhododendrons, but basically for all ericaceous plants. These are plants that have a high nutrient requirement and prefer an acidic pH value. This also includes hydrangeas, various ericas, blueberries, cranberries, cranberries, etc. Magnolias can also be optimally supplied with rhododendron fertilizer.
Can I use a different fertilizer for my rhododendrons?
A mixture of dried coffee grounds and horn meal or horn shavings is very suitable for fertilizing rhododendrons. Both components are organic fertilizers that slowly decompose and stimulate soil life. In order to avoid deficiency symptoms, you should also use compost for fertilization, whereby you should give preference to leaf compost due to its acidic pH value. Coffee grounds also acidify the soil.
How much fertilizer does the rhododendron need?
How much fertilizer you give your rhododendron depends very much on the size of the plant. Smaller specimens up to a height of around 60 centimeters are content with 40 to 60 grams of rhododendron fertilizer, larger ones up to a height of 120 centimeters need 90 grams. Even taller rhododendrons receive between 120 and 200 grams of fertilizer according to their size.
equipment
rhododendron soil
our recommendation
Compo SANA growing medium using organic soil material, vegetable matter, fertilizers, Not applicable
15.56 EUR To the productSpecial rhododendron soil contains everything rhododendrons need for healthy growth. Above all, the special substrate is lime-free and has an acidic pH value - ideal not only for rhododendrons, but also for other ericaceous plants such as azaleas, hydrangeas, blueberries, etc. You can not only use the substrate for potted plants, but also to improve the soil in the use garden planting.