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During flowering, rhododendrons are not inferior in beauty to the most attractive shrubs, even roses. In addition, the buds on most species open early, at a time when the garden is dull, and many thermophilic plants have just begun to dissolve their leaves. It is very important to feed rhododendrons in spring. And even though the flower buds have been laid since last year, the health of the plant depends on the correct application of fertilizers, and how the bush will behave in the next season.
Features of feeding rhododendrons
Rhododendron is the most extensive genus of the Ericaceae family. The number of species is not precisely determined, since new ones are discovered annually or isolated into a separate taxon. Today there are more than 1200 of them.
In Wikipedia, the figure is half that, but the author, obviously, took into account only those rhododendrons that were assigned the status "accepted". Many more species are classified as "unallocated" and are awaiting description.
For a few plants, the composition and structure of the soil are as important as for rhododendrons. Top dressing also depends on them. If the bush grows in an area abounding in sphagnum peat bogs, it will not need to be fertilized. Overly caring owners can reduce crop feeding to symbolic ones.
Where the soil has a neutral or alkaline reaction, it is necessary to constantly fertilize the rhododendron. And not from case to case, but by carefully planning the feeding scheme.
Ash cannot be used to feed rhododendron. It deacidifies the soil, like humus of animal origin. It is because of improper feeding that rhododendrons most often die. With a shortage of substances necessary for culture, and an excess of undesirable ones, conditions are created that are unsuitable for the life of a plant, and it simply dies.
Spring feeding of rhododendrons should contain a large amount of nitrogen. This substance is the main "building" element for plant organisms, it is necessary for photosynthesis, the growth of green mass and flowering. By the middle of summer, the need for nitrogen decreases and, in order not to cause a second wave of vegetation on the eve of cold weather, it is excluded from the "diet" of the crop.
Top dressing of rhododendrons in the fall lays the foundation for flowering next year and allows the shrub to winter safely. Here, other macronutrients are of great importance - phosphorus and potassium. They allow the wood to ripen, participate in the formation of flower buds, and strengthen the root system.
Soil acidification for rhododendron is especially important on soils with neutral and alkaline reactions. It is needed even where the pH level is low, but the land on the site was changed before planting horticultural crops. There are a lot of ways for this, the main thing is not to ignore the needs of rhododendrons, otherwise they will stop blooming, they will hurt, and as a result they will simply die.
How to independently check the acidity of the soil
Not always gardeners can tell exactly what kind of soil acidity is in their area, but calling a specialist to determine the pH level is troublesome and costly. In addition, this must be done every year, or even better - several times per season.
It is easy to independently check the acidity of the soil on the site. To do this, it is enough to buy litmus paper. The procedure itself looks like this:
- Several soil samples should be taken under the rhododendron bushes at a depth of 0 to 20 cm.
- The soil is thoroughly mixed, 1 tablespoon is poured with a fourfold volume of distilled water.
- Leave for 2 hours, shaking constantly.
- Take a strip of litmus paper, soak it in a solution, compare it with an indicator scale.
This acidity test is very simple, but not perfectly accurate. But it provides objective information about the pH level, and serves as a guide to action (or inaction) for hobby gardeners.
Fertilizers for rhododendrons
Now on sale there are a lot of dressings that allow you to create comfortable conditions for rhododendrons in areas with any soil. Some of them contain special acidifiers that relieve gardeners of the need to adjust the pH level separately. But such dressings are usually not cheap.
Meanwhile, it is possible to create acceptable conditions for culture without chemistry at all. True, not everyone will succeed without hassle. So, what top dressing to use should be decided by each gardener independently, based on their own conditions and capabilities.
Mineral
Now on sale you can find fertilizers for rhododendrons in any price category, domestic and foreign manufacturers. It is important to use them correctly, strictly follow the instructions and not engage in self-activity - it is better to under-feed the plant, then the situation can be corrected. With an excess of fertilizers, the bush may die immediately, or, for example, if a nitrogen-containing preparation is given in the fall or late summer, it simply does not leave after winter.
Fertilizer for rhododendrons Greenworld has shown good results, which can be used for other heather crops, hydrangeas and lupines. It contains a full range of trace elements and is used in the first half of the season - in spring and early summer.
Fertilizer for rhododendrons Florovit has a similar effect. Both dressings are in the middle price category and are of high quality.
Cheaper fertilizers can also be used. Which ones and how to apply them will be described below.
Organic
Proponents of organic farming can do without chemistry at all. For novice gardeners, this can cause an endless stream of questions, because they know two main types of natural dressing: ash and manure. And they are strictly contraindicated for rhododendrons.
Here mulching of the trunk circle with a layer of 5-8 cm will come to the rescue.But not everything is suitable as fertilizer. The best materials that allow not only to prevent weed germination and retain moisture, but also to feed rhododendrons, will be:
- Pine needles. But you can't just take it in the nearest forest if crooked or infected trees grow there - along with the litter, pest larvae and pathogens will fall on the site. You can take needles only in clean plantings, or buy (ask) in the nearest botanical garden, coniferous plant nursery - there should be enough of this stuff.Comment! Pine needles are best suited as fertilizers.
- Shredded bark of gymnosperms. Here again, it is best to use pine. Moreover, mulch, even the smallest fraction, will not work. What is needed is finely crushed fresh bark from healthy trees.So this method of fertilizing rhododendrons is only suitable for those who have a special shredder.
- Peat crumb, grass, chaff, leaves showed themselves somewhat worse as top dressing.
When decomposing, mulch acidifies and enriches the soil with useful substances, but their supply is not endless. After 2-3 months, the layer will have to be renewed.
How to feed rhododendron
Fertilizers for rhododendrons in the spring, you can choose organic or mineral. It is important that purchased drugs are specialized. Nitroammophoska or even the best feeding for other crops will not work here - they can harm rhododendrons. In the fall, in any case, you will have to use mineral fertilizers.
How to feed rhododendron in the fall
Even if the rhododendron bloomed beautifully, was not affected by pests and diseases, and the bark on young branches by the end of the season had time to woody and seems to be quite ripe, you cannot ignore the autumn feeding. It depends on them how the culture overwinters. And whether it will bloom profusely next spring.
In late summer and early autumn, you should give the rhododendron phosphorus-potassium fertilizer twice. Even in an area where pine needle mulch has been regularly changed, this should be done at least once.
A specialized nitrogen-free rhododendron fertilizer can be used, but it is difficult to find commercially available. And why? There is an excellent domestic preparation of potassium monophosphate, which is used for all perennials. It showed excellent results, and despite the low price, it is no worse than imported fertilizers.
How to fertilize rhododendron in spring
Amateur gardeners often wonder how to feed the rhododendron in the spring for lush flowering. It should be noted that if mineral fertilizers are used, they will need to be applied frequently.
And since the buds open early, and the mulching litter will not have time to decompose due to the insufficiently high temperature, the first two feeding of rhododendron in the spring should be done with chemistry even for organic supporters:
- as soon as the snow melts, nitrogen is brought in;
- after about two weeks, in April, the rhododendrons should be fed with a complex fertilizer.
For amateur gardeners who, for one reason or another, do not have the ability or desire to use special preparations, it will be useful to learn how the culture was fed before. After all, specialized fertilizers appeared not so long ago, and in botanical gardens and nurseries, rhododendrons have always amazed with their lush abundant flowering.
They were given, at intervals of 10-14 days, alternately the following nutrient solutions:
- Ammonium sulfate and potassium nitrate - 5 g of each salt per 10 liters of water.
- Urea and potassium magnesium are the same proportion.
Top dressing is carried out from April to mid-June, then stops to prevent an untimely burst of re-growth of shoots. This will prevent the rhododendron from wintering safely, and may even lead to the death of the plant.
Foliar dressing
Once every 2 weeks, it is useful to spray rhododendrons with foliar fertilizers. It is possible to dissolve preparations intended for the soil in water, but it is better to use a chelate complex for these purposes. If amateur gardeners find a special one for rhododendrons, good. Otherwise, chelates designed for conifers or lawn are perfect for replacement.
How to acidify the soil for rhododendrons
Soil acidification can only be ignored in an area where it already has a low pH. For rhododendrons, the most comfortable level is 3.5-5.5. If the soil is neutral or alkaline, it is impossible to do without acidifiers - the plants will constantly hurt, wither, and as a result they will die.
Rhododendrons, feeding which is carried out alternately with solutions of ammonium sulfate with potassium nitrate, or urea and potassium magnesium, get enough acid. The same applies to bushes, the ground under which is covered with constantly renewed pine needles mulch.
Specialized dressings also often contain an acidifier. Whether this is so, you can find out by carefully reading the instructions.
Starting in mid-June, rhododendrons are no longer given nitrogen-containing specialized fertilizers or self-formulated nutrient solutions. Only then is the pH level maintained in other ways.
How to pour citric acid on rhododendron
It should be noted right away that this method is not the best one. But if there is no other way out, watering rhododendrons with citric acid can act as an "ambulance". Some growers constantly wet their crops with an acidified solution, and claim that they like the result.
A teaspoon of citric acid is thoroughly diluted in 10 liters of water. Before watering the bush, the soil under it must be moistened.
Top dressing of rhododendrons with vinegar
In fact, watering with water with rhododendron vinegar in the spring is not a top dressing. The solution of this acid does not contain any nutrients for plants. Use vinegar to acidify the soil.
But this is the worst option - the soil deteriorates, and the rhododendron root suffers, so this should be done only as a last resort, and preferably infrequently. Better to buy a sachet of citric acid.
Add 2 tablespoons of vinegar to 10 liters of water, pour over wet soil.
Other soil acidifiers for rhododendron
It is the "other acidifiers" that are best used to bring the pH to the level necessary for the normal development of rhododendrons. These include, first of all, coniferous litter. Pine is considered ideal.
Sphagnum peat acidifies the soil well. It is also used as mulch, pouring a layer of 5-8 cm into the trunk circle.
Fertilization rules
When feeding rhododendrons, you need to pay attention to some points:
- Young or newly planted bushes should be fertilized with liquid preparations or preparations dissolved in water.
- Before using dressings, you need to carefully study the instructions and adhere to the manufacturer's recommendations.
- Fertilizers containing lime or chlorine from the "diet" of rhododendrons must be excluded.
- Phosphate fertilizers are of great importance for the culture, especially in the fall, but their abuse will lead to chlorosis.
Conclusion
You can feed rhododendrons in spring in different ways, the main thing is that the culture does not suffer from a lack of nutrients. There are inexpensive domestic fertilizers that allow simultaneously acidifying the soil, and quite expensive imported preparations in which the manufacturer has balanced macro and microelements. Proponents of organic gardening can provide rhododendrons with everything they need by using pine bedding.
