May 4, 2005

European Pine Sawfly


Now is the time to inspect mugho, Scots, red and other pine trees and shrubs for clusters of defoliating gray-green "worms."

The European pine sawfly is a common problem during the month of May. Larvae of this widespread pest are grayish-green with 2 light stripes and 1 dark stripe on each side of the body. The legs and head are shiny black. Full grown larvae, usually present by Memorial Day weekend, are about 1 inch long.

Remember to Consider the Roots


When a tree or shrub develops brown leaves, wilting leaves, poor growth, or dead branches, it's easy to focus on the above-ground portions of the plant to try to figure out what went wrong. In many cases, however, the root of the problem is exactly that - an unhealthy root system.

Diagnosing problems with underground plant structures can be difficult, especially with large plants such as trees. An accurate diagnosis requires assessing cultural practices, site factors, and environmental conditions, and possibly may require a careful excavation around the base of the plant.

Growing Elephant Ear


Elephant ear, Colocasia esculenta, is grown for its large tropical-looking foliage. Foliage colors include purple-black, green, and white/green variegated. The large heart shaped leaves are produced on 2 to 3 foot long petioles (leaf stalks)

Lilacs for Fairytales


Last and First Frost Dates in Iowa


The following chart is based on weather data collected from 1971 to 2000.* Probabilities indicate the likelihood of experiencing 32 F on or after the given date in spring and on or before the given date in fall. Cities and towns listed are grouped by their location in the state from north to south. Within each group, cities are listed from west to east.