May 4, 2001

Late-Emerging Perennials

As the growing season progresses, there are noticeable changes in the flower garden. This spring with the sudden appearance of 80-degree temperatures, perennial flowers seem to be emerging and blooming in short order. Yet, sometimes we worry when some of our prized perennials have not shown any evidence of life.

Don't worry. There are several perennials that are perpetually tardy every year. These perennials require warm soil and air temperatures to get started in the spring. Sometimes they do not emerge from the soil until June!

Does landscape mulch lead to termites in your home?

The subterranean termites found in scattered, localized areas around Iowa are routinely found in wood chip mulch and other wood products on or in the soil (lumber scraps, boards, firewood, pallets, etc.). Does this mean, as some pest control advertisements claim, that mulch attracts termites to your home or that the mulch somehow causes termites? The answer to both questions is, "no."

Rose Black Spot

Black spot of rose, also known as leaf blotch, and leaf spot, is a disease caused by a fungus called Diplocarpon rosae. The optimal conditions for disease development are 75-85 F and high relative humidity. Infection may be greatest on leaves that remain wet for six hours or longer. Leaves and canes can become infected.

Annual Vinca and Common Periwinkle

When selecting flowering annuals this spring, don't forget annual vinca (Catharanthus roseus). Annual vinca, also known as Madagascar periwinkle, is the perfect plant for sunny garden areas. In addition to being a wonderful plant for beds and borders, annual vinca can also be grown in containers, window boxes, and hanging baskets.