How to Use Epsom Salts for Stronger, More Vibrant Rose Bushes

Roses are a popular flower amongst gardeners. The perennial fills a landscape with a sense of timelessness that other flowers have a hard time replicating. But despite their appeal, roses have a reputation for being difficult to maintain. If your roses are looking a little worse for wear, there is one cure that gardeners swear by: Epsom salts. The compound contains elements that are known to reduce the risk of disease, enhance nutrient uptake, and improve flower quality.

What Are Epsom Salts?

Despite its name, Epsom salt isn't salt at all. "Epsom salts are technically magnesium sulfate," says Sandra Zazzara, support specialist at Witherspoon Rose. The chemical compound consists of elements important to plants, including magnesium, sulfate, and oxygen.

Benefits of Epsom Salts for Rose Bushes

Though Epsom salts aren't a cure-all for every rose bush concern you come across, gardeners swear the compound has a myriad of benefits that are beneficial for plants. 

Helps With Nutrient Intake 

Epsom salts are known to enhance nutrient uptake in roses. "Magnesium aids in the absorption of important nutrients, such as nitrogen, phosphorus, and potassium," says Wes Harvell, rose category manager of Jackson & Perkins. "When rose plants have sufficient magnesium levels, they can more effectively utilize these nutrients, promoting overall growth and development."

Additionally, Epsom salts' sulfur content also helps with nutrient uptake. "Sulfur aids in the production of amino acids, enzymes, and vitamins, and it plays a role in the formation of proteins within the plant," says Harvell. "By ensuring an adequate supply of sulfur, Epsom salts can contribute to improved nutrient availability and utilization in rose plants."

Increases Flower Quality 

The magnesium in Epsom salts plays a major role in chlorophyll production, which is responsible for the green color in leaves. "Epsom salts can help prevent magnesium deficiency in roses, resulting in healthier foliage," says Harvell. What's more, additional magnesium supply may produce more blooms, larger flowers, and support the formation of strong stems. 

Protects Against Disease 

Epsom salts contain sulfur, which is believed to have fungicidal properties that enhance a rose's natural mechanisms against certain diseases. "While research on this topic is limited, some gardeners claim that regular applications of Epsom salts can help reduce the risk of diseases like black spots, powdery mildew, and rust in roses," says Harvell. Note that the effects may vary depending on the specific disease and environmental conditions.

Improves Soil pH

That sulfur can also help lower the pH level if your soil pH is too alkaline. "Roses generally prefer slightly acidic to neutral soil conditions—pH 6 to 7—and maintaining the appropriate pH range can improve nutrient availability and uptake for the plants," says Harvell. 

Signs Your Rose Bush Needs Epsom Salts

Before using Epsom salts for roses, you should determine if your plants need it—and if your soil is healthy enough to correctly utilize it when it's applied. "It's important to note that not all rose plants necessarily require Epsom salts" says Harvell. "Before applying any amendments, it's advisable to consult with local horticulturists, rose specialists, or gardening experts who are familiar with the specific soil and climate conditions in your area."

Do a Soil Test

Start by conducting a soil test to assess the nutrient levels and pH of your soil. “This will help identify any potential deficiencies or imbalances that may impact your roses' health," says Harvell. "If the soil test indicates a magnesium deficiency or alkaline pH, Epsom salts could be beneficial."

Observe Your Plants

Observe your plants for signs of magnesium deficiency before applying Epsom salts. "Symptoms may include yellowing leaves (with the veins remaining green), stunted growth, or reduced flower production," says Harvell. "If your roses exhibit these symptoms, it could indicate a need for magnesium supplementation."

Also pay attention to the performance of your rose plants. If your roses are lacking vigor, have pale leaves, or are not producing satisfactory blooms, applying Epsom salts may improve their health and appearance.

How to Apply Epsom Salts to Rose Bushes

The easiest and most common approach is to apply the salt directly to the soil around the rose plants. Use about a 1/2 cup to 1 cup of Epsom salt per plant, or 1 teaspoon of Epsom salt per 1 foot of the plant's height. 

1. Sprinkle Epsom salt evenly around the base of the plant, keeping it a few inches away from the stem to avoid direct contact. 
2. Use a rake or hand cultivator to gently work the Epsom salt into the top layer of soil.
3. Water the plants thoroughly after application to help the salts dissolve.
   

How Often to Use Epsom Salts on Rose Bushes 

The best time to apply Epsom salt is during early spring as new growth begins or during the active growing season. "Applying Epsom salts at this time helps ensure that the magnesium is readily available to support the plant's growth, nutrient uptake, and flower production during the crucial period," says Harvell. As a general rule, Epsom salts should be applied every four to six weeks during the growing season, which allows the plants to absorb the magnesium while avoiding nutrient imbalances.

Avoid using Epsom salt during extreme heat or drought. "High temperatures and dry conditions can potentially stress the plants, and applying salts may further exacerbate the stress," says Harvell. you should also avoid using Epsom salts in excess, which may lead to an imbalance of nutrients in the soil.