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Epsom Salt for Rose Bushes

By Deborah Harding
Roses benefit from Epsom salts when soil magnesium is low.
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Old-time gardeners used Epsom salts to enhance rose growth and keep black spot at bay. Although there is little research proving the mineral helps roses grow, Epsom salts are frequently used in gardening. The discovery of Epsom salts was in Epsom, England, where natural springs were used as spas for healing. Nehemiah Grew ran one of those spas and named the salts after the town in 1695. Epsom salts are made up of both magnesium and sulfate. Adding it to the soil treats magnesium deficiencies.


Magnesium is a mineral plants need to form chlorophyll, which gives plants their green color. Plants use chlorophyll to make food by using the sun’s rays. Magnesium strengthens cell walls, allowing the plant to receive necessary nutrients in the soil enabling it to grow.


Sulfate helps with production of chlorophyll, and allows plants to be infused with nutrients in the soil including nitrogen, phosphorus and potassium. Sulfate also helps to balance soil pH when it is very acidic.

Signs of Deficiency

Look at mature rose leaves to check for magnesium deficiencies in the soil. If the leaves are solid green, a magnesium deficiency is unlikely. Yellow leaves with green around the leaf veins creating an arrowheadlike shape in the middle indicate that there is a magnesium deficiency in the soil.

Use of Epsom Salt in the Garden

An old method of using Epsom salts with roses is measuring the rose bush’s height first, and then sprinkle 1 tablespoon of Epsom salts per foot of height into the soil around the plant’s base. Water it afterward to ensure incorporation into the soil. A 2-foot height bush would take 2 tablespoons of Epsom salt. Apply it in the spring and again in summer if a deficiency arises. Another method of application is dissolving Epsom salts in a gallon of water and applying to the soil around the rose.

Other Information

Soils with a pH higher than 7.0 with high calcium and potassium levels usually have magnesium deficiencies. Test the soil. Epsom salts help give rose stems and leaves a healthy green color. The salt does not build up in the soil and therefore, making it safe for use. Epsom salts make rose bushes fuller and greener, and may help them produce more blooms.


About the Author


Deborah Harding has been writing for over nine years. Beginning with cooking and gardening magazines, Harding then produced a gardening and cooking newsletter and website called Prymethyme Herbs in 1998. Published books include "Kidstuff" and "Green Guide to Herb Gardening." She has a Bachelor of Music from Youngstown State University and sings professionally.