Protecting plants from high temperatures

Mulches provide many benefits to garden and lawn plants, according to horticulture specialist

Gaylord Moore. "Benefits vary with the material used, the type of soil, the kind of plant and the cultural practices used," Moore said. "But mulches can also be used to make landscapes more attractive and usable and to reduce the amount of maintenance work."

Homeowners and gardeners have two different types of mulch to choose from: Organic and inorganic.

Most of the organic mulches eventually decompose and add value to the soil structure and some nutrients. Inorganic types are more permanent and offer no value to soil building. Inorganic mulches are most useful around permanent plants such as trees

and shrubs. "It is also a good idea to use spun-bonded or woven landscape fabrics as a barrier between the mulch and soil to prevent weed growth and make the mulch more effective," Moore said.

Mulch can also offer winter protection to plants by stabilizing temperatures and preventing so-called "plant heaving" from freezing to thawing.

"Mulches may prevent the extremes of temperatures that jeopardize some more tender perennial," he said. "Mulches can also prevent freezing of the root system that may affect water movement into the plant."

When it comes to specific plant types, there are other important considerations when using mulch according to Moore.

• Bulbs: Lilies benefit more from mulching than any other group. Two to three inches of wood shavings, straw or other lightweight material give winter protection to the more tender species. Small, shallowplanted bulbs can be pushed out of the soil by alternate freezing and thawing but light mulching can largely prevent this effect.

• Evergreens: Mulches help prevent winter drying of evergreens, which causes foliage to become scorched and discolored over winter. Plants that should always be mulched are azalea, boxwood Chinese and Japanese hollies and rhododendron.

• Strawberries: Mulch strawberries with clean straw in mid-December. Mulch offers winter protection to the crowns and prevents heaving from freezing and thawing of the soil.

• Perennials: Perennials that most often need winter protection include baby's breath, bellflower, chrysanthemums, delphinium, hardy gloxinia, hypericum, linum, lupine, Oriental poppy, Stoke's aster, thrift and thyme. When using a heavy layer of mulch on perennials, gradually remove it during the onset of warmer weather in late winter.

• Roses: By December, provide adequate winter protection with a mound of finished compost, garden soil or coarse peat. The mound should be about 8 inches deep across the center of the plant.

- University of Missouri Extension