Spectacularly bloomingazaleas and rhododendronsmake any garden look amazing. However, they have quite specific requirements as to the soil composition and its pH, so it is worth taking care of a suitable substrate before planting them. Seewhat kind of soil for azaleas and rhododendronsis the best and how to prepare such a substrate yourself!
What soil for azaleas and rhododendrons?
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Soil for rhododendrons. Recommended composition and pH
Rhododendrons, which include both rhododendrons and azaleas, thrive in moist, well-drained, well-aired soil with a high organic content.The thin, hair-like roots of these species do not tolerate heavy, wet soils, because then they have problems with growing and absorbing nutrients. Under the influence of water remaining in the soil, the roots of rhododendrons rot and become susceptible to diseases, especially those with a fungal basis.
The soil for rhododendrons must also be acidica. A soil pH of 3.5 - 5.0 is recommended. Higher soil pH causes growth inhibition and yellowing of leaves, i.e. chlorosis, because the plant cannot absorb iron from the substrate. This component is involved in photosynthesis and the formation of chlorophyll, responsible for the green color of the leaves.
For planting azaleas and rhododendrons, you can buyready-made soil mixture for rhododendronsand acidophilic plants. For example, soil for blueberries and acidophilic bushes of the Target brand will work. This is just an example, because the choice of this type of substrate is very large.
How to prepare soil for azaleas and rhododendrons?
The soil for azaleas and rhododendrons can also be prepared by ourselves
To properly acidify the soil for rhododendrons, about half of the soil should be acidic organic material: acid garden peat, composted needles of coniferous plants, composted pine and fir bark. Pine bark is especially valuable because it inhibits the development of pathogens responsible for the occurrence of fungal diseases that cause root rot, such as, for example, phytophthora.The remainder of the substrate can be ordinary compost or garden soil (e.g. obtained from holes dug for planting new plants). Inorganic materials that can loosen the soil, e.g. perlite or vermiculite, can also be added to the mixture.
What soil for azaleas and rhododendrons?
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How to acidify the soil to rhododendrons?
Ahow to acidify the soil for already growing rhododendrons ? A layer of organic mulch made of materials such as shredded pine bark and needles of coniferous trees and acid peat help to acidify the soil in a natural way, and additionally retain moisture and suppress weeds. It is best to spread such mulch in the fall to protect the shallow roots of azaleas and rhododendrons from freezing during the winter, and in spring to rake it with the soil to mix it shallowly.
On an ad hoc basis, acidifying fertilizers dedicated to acid-loving plants can also be used, which quickly reduce the pH of the substrate. For this purpose, ammonium sulphate or a specialized acidifying fertilizer for acid-loving plants can be used.
Acidification of soil with acid peat
Fig. © Joanna Białowąs
Is soil for conifers suitable for rhododendrons?
The substrate for conifers is usually a mixture of strongly and poorly decomposed high peat.Due to its acidic reaction and high water capacity, it is perfect for planting and transplanting not only coniferous trees and shrubs, but also plants that require a low pH substrate: azaleas, rhododendrons, heathers, heathers and blueberries.
Is rhododendron soil suitable for hydrangeas?
Substrate for rhododendronsis most often dedicated to other acidophilic species, including hydrangeas. Hydrangeas, like azaleas and rhododendrons, need a loose, fertile, humus and acidic soil. The pH of the substrate determines not only the development and he alth of the hydrangea, but also the color of the inflorescences. The flowers of some varieties of garden hydrangea turn blue or purple when grown in acidic soil of 4.5-5.0 pH, and pink in slightly more alkaline soil - 5.0-5.5 PH. To sum up - withthe soil for azaleas and rhododendrons is suitable for the cultivation of hydrangeasand will favor the blue color of its flowers.
MSc Eng. Anna Błaszczak
