Rhododendrons are beautiful flowering plants that come in a wide variety of colors and sizes. Epsom salts on rhododendrons are a simple way to fertilize these plants. All flowers have mineral requirements that they must get from the soil, and fertilizers must often be used to provide these nutrients. Mulches of natural materials can go a long way toward enriching the soil, but additional nutrition, such as Epsom salts on rhododendrons, is often needed for optimal blooming beauty.
If the soil is already fertile and rich, rhododendrons, and their cousins, azaleas, often do not need additional fertilizers, such as Epsom salts on rhododendrons. There is already enough nutrition is the soil. Sometimes, though, if you add a mulch, you will need additional fertilizer for your plants.
Fertilizing and Mulches
The reason for this is that certain mulches, such as wood chips or sawdust that are not completely decomposed, need to continue to decompose, and this uses up nitrogen from the soil. Extra nitrogen will have to be added in the form of a fertilizer.
When using fertilizers on any type of plant, it is possible to get too much and “burn” the plant. Rhododendrons and azaleas do not require as much fertilizer as many other plants, such as decorative grasses and shrubs. Rhododendrons are acid lovers, and sometimes need an appropriate fertilizer to be applied either late in the winter or early in the spring. Epsom salts on rhododendrons are not a complete fertilizer, but can provide minerals to these plants.
Epsom salts on rhododendrons specifically supply magnesium to the plants. If your rhododendrons and azaleas are not getting enough magnesium, they will probably have yellowing spots on the more mature leaves. The spots will be in the leaf areas between the veins. If the leaves on your rhododendron are fully green, it is a sign that the plant is getting enough magnesium, and you do not need to use Epsom salts on them.
In addition to Epsom salts on rhododendrons, sometimes these plants lack phosphorus. If the plants have enough phosphorus, they will produce flower buds early in the season. Phosphorus is a common addition to commercial fertilizers.
Another mineral that rhododendrons sometimes need supplemented is iron. The symptoms of iron deficiency are similar to those of magnesium deficiency – which responds to the use of Epsom salts on rhododendrons of course. The main symptom of iron deficiency is yellowing of patches on younger leaves.
Adjusting the pH of the soil can help the plant acquire the needed iron from the soil. Remember that rhododendrons love acid soil. The pH should be low for these plants. Iron deficiency can also be caused by building materials, including mortar, being stored near the plants.
In the event of an iron deficiency in the soil your rhododendrons are growing in, you can add ferrous sulfate as a fertilizer. Another option is to spray the leaves with chelated iron. Whatever you do, adjusting the pH is necessary for long term health of your rhododendrons. Using Epsom salts on rhododendrons will not help with iron deficiency, however.
Another mineral that is helpful for the health of rhododendrons is calcium. This mineral is often supplied to garden areas through the application of lime to the soil. Another possible soil amendment is gypsum.
A problem with lime, though, is that it raises the pH, which makes the soil a bit hostile for these acid lovers. While Epsom salts on rhododendrons will not help the pH or a deficiency in calcium, the magnesium this substance adds can increase the health of your rhododendrons.