I'd say 1/4 cup, if you know there is a deficiency.

That's about what I have used in the past when I put Epsom Salt down. A little less for minis though.

Why do you think you need Epsom Salt (magnesium)?????

In an earlier post, I was told the yellowing leaves at the base of this rose was caused by magnesium deficiency.

Using chlorosis patterns in leaves to determine a nutrition deficiency is a bit of a crap shoot because there are many overlapping/vague chlorosis patterns. You really should take a soil sample & submit to a reputable lab for analysis. Applying too much of one nutrient can mess up the availability of other nutrients to your plant. So again my advice is, do a good quality soil test before adding a bunch of nutrients, especially the secondary & micro nutrients.

Hey Gary! Did you incorporate the Mg sucrate into these soils? If so, the Mg deficiency shouldn't be an issue. How is the rest of the garden and roses? How are effected roses doing today?

Send another sample my way and we can see where things are at!

I would do a soils test before applying epsom salts. In most of Southern California, there are PLENTY of mineral salts in the soil and water.

soilhugger541: are you Aaron?