Dear Problem Lady – December 2017


My husband thinks oak leaves decompose too slowly to use them as leaf mulch. Do you agree?
Yes. Oak leaves would work if combined with other leaves. All leaves must be chopped up before being used as mulch. Most of us don’t have lawn mowers with which to chop leaves. It may be easier (and still fairly inexpensive) to buy a local product called Leafgro. It is made of already-composted leaves.

Is it harmful to recycle swimming pool water to use in a garden?
Not at all. Apparently once pool water has sat in full sun for a day or two, the sun’s ultraviolet rays will have rendered the chlorine inactive. For the safety of swimmers, chlorine must be continually cycled into pool water. Turn off the pool pump and wait a few sunny days before using pool water in the garden.

What is mildew?
It is a type of mold, pale gray or white in color, covering the surfaces of plant leaves of peonies, zinnias, monarda and roses. You see it as the season wears on. Sometimes called “powdery mildew” it is a grayish white, and usually does not kill a plant. Remove the whitened leaves if you can. Mildew can live through the winter. At the end of the season remove and destroy all mildewed foliage. Also avoid dense plantings that lack air circulation. Mildew thrives on humid air — hard to avoid in DC.

What are Nematodes? This summer skunks and raccoons dug up our so-called lawn in the country. My garden helper said the only thing to stop them was nematodes.
Maybe. Nematodes are microscopic insects, not visible to the naked eye. Nematodes eat grubs. Grubs are those round, one-inch white worms – some people call them cutworms – that feed on grass roots, go deeper in winter, and then turn into beetles in the spring. In slightly less urban places than DC you see hungry animals digging them up to eat. This digging greatly harms lawns and gardens.

Nematodes can be purchased and “watered into” an area that animals have dug up. From one point of view, the animals were doing you a favor, eating grubs that would turn into beetles. But they can wreck a lawn. Enter the nematode solution, which may or may not kill the grubs (you won’t know for a year) and thus stop animals from digging for them. While nematodes are expensive, and a whole lot of work to apply, they could save your lawn or garden.


The next public meeting of the Capitol Hill Garden Club occurs January 8, 2018 at the NE Public Library, corner of Maryland Ave. NE & 7th St. NE. Meetings start at 7 pm and are free and open to all. Membership details:

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