The Bay Gardener by Dr. Frank Gouin

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Let Your Lawn Breathe

Compost those leaves; don’t let them lie

Colorful fall leaves lying on your green lawn may look attractive, but allowing those leaves to collect can damage cool-season grasses such as bluegrass and tall fescue. Cool season grasses produce most of their roots and absorb most of their nutrients during the fall and early winter months. Allowing fallen leaves to shade these grasses during their most active periods of growth and development can seriously reduce their vigor and make them more susceptible to diseases and winter injury.

During periods of heavy leaf drop, lawns should be raked, blown or vacuumed at least twice weekly to prevent the leaves from shading the grasses. Don’t use a mulching mower to grind the leaves into powder to be deposited as mulch.

Mulching mowers were designed to mow and grind grass clippings and deposit them back in place to decompose and release their valuable nutrients back into the soil. Because grass clippings contain 70 to 80 percent water and three to four percent nitrogen, they will compost readily, providing the grass is cut at least three inches tall, thus allowing natural recycling of nutrients. Tree leaves contain less than 10 percent moisture, less than 0.02 percent nitrogen and have a carbon to nitrogen ration of 80:1. This means they will not decompose readily when mulched in place with a mulching mower, resulting in an accumulation of thatch.

The leaves that you rake, vacuum or blow can be used to make great compost. Leaves that are collected by vacuuming either with a bagging unit on your lawn mower or with a sweeper will compost faster than leaves that are raked or blown, as vacuuming crushes them into small particles, allowing them to be composted faster. See next week’s Bay Gardener on composting leaves.

Vines Bothering You? Kill Them Now

Q How can I control a wisteria plant and ivy — which has taken over my bushes and azaleas and is climbing up the trees — without killing the trees and bushes?

–Mrs. M. V. Pokey, Prince Frederick

A To control the wisteria and ivy growing on your trees, simply cut the stem of the vines near the ground and paint the cut end of the stump with a mixture of either Weed-B-Gone or Trimex diluted with equal amounts of water. Be careful not to spill the mixture on the desired plants and on the soil. Wear protective clothing and rubber gloves. To kill all of the roots, this treatment should be done as soon as possible this fall.