The dictionary describes mulch as a material spread on the ground to reduce evaporation, maintain even soil temperature, prevent erosion and control weeds. The dictionary does not mention the aesthetic value of mulch but this attribute makes mulch currently very fashionable. Evidence of this is the proliferation of roadside vendors of mulch in Butler County over the past year.

Various mulches have traditionally been used to conserve moisture and suppress weeds. Both organic and man-made materials have been used. Some of the more common mulches are bark, wood chips, plastic film and newspaper.

A recent trend is to use mulch in a rainbow of colors around foundation plantings and trees. Most colored mulches are made from recycled wood pallets and are dyed red, black, blue and gold.

A number of wood mulches are available including pine bark, cedar and other hard woods. Another organic mulch is cocoa shells. Cocoa shells have been used for many years in the rose garden at Hershey.

Stones and rocks are available and include seashore pebbles, pink and white stone, green stone, blue stone, red stone and several sizes of river rock.

The newest product on the market is rubber nuggets, which are made from automobile and truck tires. These nuggets are dyed red, green and brown.

While all mulches have the ability to reduce or eliminate the need to weed and water, they also have shortcomings. All wood mulches break down over time and need to be supplemented with additional mulch. As the wood mulch rots, a fungus can develop which shoots out dark colored spores that are attracted to light colored surfaces such as house siding. This is artillery fungus and the spores are thrown up to 15 feet. The spores attach themselves to the surface they land on and permanently disfigure the surface. No remedy has been found for cleaning the dark-colored spots from items such as painted and vinyl siding.

Some wood mulches can produce a very unsightly growth on shrubs and flowers. This is a slime mold referred to as "dog-vomit" fungus. The bright yellow and orange slimy masses are up to 1 foot in width and can grow over an entire plant. The slime will not injure the plant and in a few days will dry out and turn brown and eventually appear as a white powder. The powder can be removed with a stream of water from a hose.

Cocoa shells are an attractive mulch when first applied but over a period of time will discolor. The newest mulch, rubber nuggets, appears to solve a number of problems. It provides an ecological solution to the millions of vehicle tires that are discarded each year. It is long lasting and does not support fungus or slime activity. It does have one major obstacle — its current price is $260 a cubic yard as compared to $18 to $40 a cubic yard for the various wood mulches.

All mulches, vegetable, mineral and man-made, have two disadvantages. Since one of the reasons for using mulch is to conserve moisture, this constant supply of moisture in the soil provided by the mulch is an ideal breeding area for snails and slugs. They must have moisture at all times or they will die. Mulch that is in contact with tree trunks keeps the bark continually moist and decay will eventually occur.

Garden talk plannedPenn State Master Gardeners Susie Chastney and Julie Habsburg will be presenting a talk on garden design and container gardening at the Seven Fields Trial Garden Site on Castle Creek Drive in Seven Fields at 7 p.m. Thursday.The garden site is at the Community Park by the pool house and ballfields. The program will discuss three different theme gardens with tips on annual, perennial, shrub and tree suggestions for each garden.For information, call 724-779-1007.Pete Hale is a Master Gardener with the Penn State Master Gardener program.