I have a bad-looking maple tree in my backyard. There has been a considerable amount of leaves falling to the ground. Some of the leaves have burnt brown areas. We have another maple 100 feet away and it is fine. Both maples are about 15 years old. What might be wrong?

The causes are fungal and bacterial diseases. Tar spot and petiole borer flourish in wet weather. Tar spot started in the spring with a tiny infection the size of a pinpoint that spread into a yellow spot as summer progressed. Although unsightly, it is a harmless, nuisance disease. Similarly, petiole borers won’t do any real damage to the tree, but the tiny insects that bore into and weaken the leaves make their presence known by the cosmetic changes to the leaves. Spraying will not help because the petiole borers are now inside the tree and impervious to surface applications.

It is advised that leaves be raked up and removed as often as possible and not run over with mulching lawn mowers. Allowing the leaves to remain under the trees and mowing over them can cause microbes to spread and the disease can return next year. Diseased debris can be burned, if local ordinances permit burning, or composted in a compost pile where internal temperatures reach 130 degrees. Trees should not be fertilized after August 1 because that encourages new growth that will be tender and vulnerable to colder temperatures.

Mulching is a good practice in flower beds. Should I also mulch my vegetable garden? If so, is it appropriate to use the same mulch as I use in my flower beds? What is this I hear about using colored plastic for mulch?

Mulching your vegetables is good for the same reasons. It reduces the loss of moisture during hot periods, keeps plant roots cool, and reduces the number of weeds that can grow to compete for soil nutrients. Know your vegetables because some will thrive in dense conditions. They will naturally crowd out the weeds. Organic mulches such as ground leaves, straw, pine needles, and grass clippings also add food for soil-dwelling organisms and eventually decompose into soil themselves. Avoid more than a couple inches of mulch around your vegetables. Overmulching can absorb the water, retard soil warmth, and even change the pH and nutrient content of your soil.

As for the colored plastics advertised, be sure to understand what the product is made for. Most often seen is black plastic. It is cheap, provides good weed control, and warms the soil. However, it does prevent water from penetrating. IRT (Infrared Transmitting) plastic provides good weed control since it blocks the visible light that weeds need for growth. However it costs more than the traditional black and still acts as a water barrier. SRM (Selective Reflective Mulch) is the red plastic marketed. It offers poor weed control and prevents water penetration, but it does warm the soil.

There is planter’s paper mulch which offers good weed control, lets water permeate, and is biodegradable as well. Landscape fabric provides excellent weed control, allows water and air to permeate but does not raise the soil temperature. It is four times more expensive than plastic, but it is longer lasting and can be reused.

The above products serve different purposes. You need to determine what factors you wish to control the most and how much you want to spend.