August 13, 1999

Black Rot of Cabbage

Black rot is a bacterial disease that affects crucifers (vegetables in the cabbage family). The bacterial pathogen, Xanthomonas campestris pv. campestris, is particularly damaging to cabbage and cauliflower, but turnip, rutabaga, collard, kohlrabi, and Chinese cabbage are also susceptible. Broccoli is somewhat more resistant, and radish is usually highly resistant.

Division of Herbaceous Perennials

Herbaceous perennials are commonly divided for three reasons: to control size, to retain vigor, and to propagate a prized perennial. Vigorous perennials may grow so rapidly that they choke out neighboring plants in the flower bed. Other perennials decline in vigor if not divided at the appropriate time. One of the easiest ways to propagate a prized perennial is to divide the plant into two or more smaller plants.

The best time to divide perennials varies with the different plant species. The appropriate time to divide widely grown perennials is presented below.

Something Other Than Cattails in Wetland Gardens

Wet, marshy land is not terribly hard to find in Iowa. Most are easily announced by their tall, gracefully swaying cattails. Cattails (Typha latifolia) spread by thick rhizomes under the soil and create an extensive network of fibrous roots. Cattails are especially drawn to wet marshy areas, more specifically - wet, marshy, nitrogen rich soil. They are commonly found in areas like sloughs in farm fields, farm ponds, and drainage ditches.