Epsom Salt Helps Plants Deficient In Magnesium

Q: Should I put Epsom salt on my chrysanthemums now? What solution should I use?

A: Epsom salt or magnesium sulfate are often used to supply magnesium to plants which are showing a deficiency of this mineral. Dolomite lime also provides magnesium but because dolomite lime raises the soil pH, Epsom salt is often used. Epsom salt tends to lower the pHand since it is a salt, it's more readily available to plants.

Unless your chrysanthemums are showing a magnesium deficiency, or a soil test has indicated a deficit of this important element, it is probably not needed.

Magnesium deficiency is most often indicated in plants when the older leaves become chlorotic (yellowing between the veins or marginal yellowing with the mid rib area remaining green) or when the foliage curls upward along the margins. Dissolving a tablespoon of epsom salts in a gallon of water and spraying it on the foliage of deficient plants can alleviate the problem.

Q: I have moss all over my yard, probably because much of it is shady and wet. I also believe my topsoil is too shallow and acid. I plan to correct the pH and add lots of topsoil. Is this a good idea?

A: Your yard is loaded with moss, not necessarily because your soil has an acid reaction (virtually all soils in Western Washington are acid) but because of the other conditions you describe. Unless the shade and moisture problems are corrected moss will continue to invade regardless of the pH.

Adding and incorporating topsoil to the native soil may help provide a better situation for grass and other plants to grow, thus enabling them to compete effectively with the moss. You must also deal with the other problems. Recommended grasses (perennial ryegrass and fescues) generally do well so long as the pH isn't too low, say below 5.8.

Q: We had a spruce tree in a pot for three years. It has suddenly turned brown. What now?

A: If the new growth is beginning to expand and only the previous seasons' needles have turned brown, it's probably showing the effects of a winter spruce aphid attack. These small green aphids suck the life out of the older foliage, which begins to fall off in spring about the time the new needles are coming on. All spruces should be monitored for these small green monsters through the winter, and, if found in numbers on the needles, use insecticidal soap or other insecticide labeled for such use to get rid of them.

If the entire tree is brown and no new growth appears, your plant may have been winter-killed. The roots of plants in pots on top of the ground are often killed in winter by low temperature.

Q: What is the best way to get rid of bamboo?

A: The best way to get rid of bamboo is to have someone who might want it come to your place and dig it out. (Bamboo Gardens of Washington, 868-5166, may be able to arrange to remove your unwanted bamboo.)

Constant cutting will eventually starve it out, but any effort of this sort must be consistent.

Roundup is an herbicide that is often used to control bamboo. It is applied to the foliage and taken into the roots where it accomplishes its task. Several sprays may be required.

Gardening runs Friday in Scene and Sunday in Home/Real Estate. It is prepared by George Pinyuh and Holly Kennell, Washington State University/King County Cooperative Extension agents, Mary Robson, Master Gardener program assistant, and volunteer Master Gardeners.