- Fertilize the most important thing about rhododendrons
- Best fertilizer time and dosage
- Fertilize large-scale rhododendrons yourself - but how?
- tips and tricks
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In spring, luxuriantly blooming rhododendrons delight our senses. This annual splendor requires an evenly dosed supply of nutrients. Fertilize rhododendrons - but do it right! More on the basics of healthy evergreen plant growth…
In order to support good growth of the rhododendron, the right fertilization plays an important role. Because the root system of rhododendrons branches out widely on the surface, nutrients must be able to be absorbed directly in the soil. To fertilize rhododendrons, it is best to use organic fertilizers or special rhododendron fertilizers.
But compost, leaves and coffee grounds also provide the plants with organic nutrients. In addition, the use of organic fertilizer prevents over-fertilization.
Fertilize the most important thing about rhododendrons
Do without fertilizers that are enriched with lime such as rock dust. Most rhododendron varieties react sensitively to calcareous soils in addition to a pH value that is too high. On the other hand, like all shrubs, they appreciate mulch in loose soil.
Best fertilizer time and dosage
Rhododendrons that are ideally placed in semi-shade without waterlogging in slightly acidic soil benefit considerably from the right fertilizer. Even if the location or soil do not offer ideal conditions for the easy-care ornamental shrubs, good fertilizer compensates for the disadvantages. From April to October is the best time for an evenly dosed food intake.
Caring for ornamental trees naturally means meeting special requirements in terms of location and nutrient supply. How much fertilizer depends on the size of the plant and leaves. The rule of thumb is the following dose per square meter:
- Specimens up to 60 cm - 40-60 grams
- Specimens from 60 to 120 cm - 90 grams
- Specimens over 120 cm - 120-200 grams
Loosely work the first low-salt depot fertilizer application into the top layer of soil under the outer third of the leaf crown. An additional addition of horn shavings (32.93€) with 50 - 70 grams per square meter promotes deep green foliage and forms plenty of flower buds.
Good to know: Do not fertilize freshly planted rhododendrons directly. But only in the next spring, when the shrub has developed strong roots.
Fertilize after rainy months
Fertilizing rhododendrons is recommended at the beginning of July. Especially the depleted soil after a rainy spring allows you to fertilize from 30 to 50 grams per square meter. Half the fertilizer is sufficient for small-leaved rhododendrons.
Don't forget: Water plants sufficiently after each nutrient application.
Yellow leaves alarm - high time for special fertilizer
Rhododendrons that grow, green and bloom need trace elements, magnesium, nitrogen and phosphorus. Yellow-colored leaves are an alarm signal for acute nitrogen deficiency, . which requires immediate care so that the plant grows healthy green again.
Compost and coffee grounds as organic fertilizer
Regular composting never hurts. The soil stores moisture better, remains loose and rich in nutrients.
Coffee grounds contain phosphorus, potassium and nitrogen. All three have a metabolism-activating effect. Either add fresh coffee grounds to the irrigation water or spread them directly around the plant. Because fresh coffee grounds quickly become moldy, you must first dry them on a plate or tray. Leftovers of the dried fertilizer can be stored in an airtight container for several months.
Potting soil mixed with coffee grounds is ideal for potting a mini rhododendron. The slightly acidic pH of coffee neutralizes soil with too high a pH and calcareous irrigation water. It also drives away some pests.
Fertilize large-scale rhododendrons yourself - but how?
In older, large rhododendron areas, the pH value of the soil is often above pH 5. We therefore recommend a soil analysis using test sticks from the garden trade.
Scattering 200 grams per square meter of uncleaned sulfur flower lowers the pH of the soil surface. This is available in drugstores or gardening companies. This is followed by fertilizing with a special organic-mineral rhododendron fertilizer classification
8 - 5 - 8 - 3. Around 100 grams per square meter.
From mid-April you can support them with an inexpensive dose of blue fertilizer. at the beginning of the planting season the growth of the giant rhododendron with 60 grams per square meter.
Important: Add 40 grams of kieserite per square meter to every fertilizer to ensure an optimal supply of magnesium.
tips and tricks
You can fertilize with coffee grounds all year round. For a super fertilizer, mix coffee grounds with horn shavings (€32.93) and spread lawn clippings on top. This saves money and waste.