Helen Chesnut’s Garden Notes: Pulling horsetail weeds encourages new growth

Dear Helen: I’ve been pulling up horsetail plants on my property and putting them on the compost. When I mentioned this to gardening friends, I was told that, because the plants extract heavy metals from the soil, they are harmful additions to a compost heap. Is this true?

H.M.

It is true that horsetail has been used to help remediate soils polluted by heavy metals. The plants’ extensive and incredibly deep roots are efficient at drawing metals from the soil. The amount of heavy metal in the plants will depend on how much is in the soil. The highest levels are found in areas where the metals have been mined.

I doubt that the soil in most home gardens will be heavily laden with dangerous metals, but if this is a concern the history of the land could be looked into. In benign soils, the plants extract and hold minerals that are useful additions to a compost.

Personally, because this is such an aggressive weed, I would treat the stems before composting them. Either soak them in bins of water for a week or lay them out in the sun on plastic sheeting to dry thoroughly.

Your email indicates that you don’t mind the horsetail on your property. Most gardeners regard the plants as pernicious weeds, almost impossible to control. Should you wish at some point to begin curtailing their spread, refrain from pulling the plants up or digging them. These actions prompt underground nodes of growth to sprout new plants.

A preferred control is to keep cutting the stems to the ground, beginning with the leafless, spore-bearing spring stems. Cut them before they can form and spread spores, which can germinate in moist soils. Then cut down the leafy stems that follow. Continued cutting will gradually weaken the roots.

If it suits the situation, an early summer cutting could be followed by covering the area with thick black plastic for a year. If you don’t like using plastic, another option is to cover a horsetail-denuded area with cardboard thick enough to hold together well for at least a year. Top it up with layers of newspaper if you wish. Then cover with a thick mulching material.

Dear Helen: In the last few years an Italian prune plum tree in my yard has produced only around 20 plums each year. The tree is an old one, dating back to the 1960s I think. I would be sad to lose the tree, but I fear it is in decline. What can I do?

P.C.

Fruit trees, like most living things, have a finite life span. For prune plum trees, the average is 15 to 20 years, with 30 years being exceptional. Our damp coastal climate renders plum and other soft tree fruits susceptible to a number of diseases that can weaken a tree and further limit its productive lifetime.

My 40-year old prune plum tree still yields good crops of delicious plums, but parts of the tree are beginning to die

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