July 26, 2002

Digger Wasps

At least 3 different species of wasps construct nests in the ground in Iowa. These "digger wasps" include the cicada killer wasp, the largest wasp found in Iowa. Cicada killer wasps may be up to 2 inches long. They are black with yellow markings on the thorax and abdomen and they have rusty colored wings. The great golden digger wasp is slightly smaller. The abdomen is reddish-orange except at the tip, which is black. A third species is 1-inch long and completely black and iridescent blue wings.

Maintenance of Perennial Beds and Borders

Perennials are attractive additions to the home landscape. However, they require good care. The following are important cultural practices.


Mulches are an excellent way to reduce maintenance chores in perennial plantings. Mulches conserve soil moisture, reducing the need to water. Mulches also help control weeds by preventing the germination of annual and perennial weed seeds. Additionally, mulches prevent the splattering of soil onto foliage and flowers. This keeps the plants cleaner and may reduce disease problems.

Perennials with Silver Foliage

Silver or gray is an interesting color in the landscape. Similar to white, silver has the ability to soothe and blend with other colors. Yet unlike white, metallic colors often contrast or stand out in green landscapes. Visualize how Colorado Blue Spruce (Picea) or Dusty Miller (Cineraria) shine in their surroundings. There are many perennials that have the same ability to "sparkle" in your garden. As an added benefit, many silver foliage plants prefer full sun with dry soils making them excellent "summer-tolerant" performers in the garden.