May 17, 2002

Plant Source References

It can be frustrating driving around to various garden centers or leafing through mail-order catalogs searching for a specific perennial, shrub, or fruit tree. Fortunately, there are several books and an online service that can help the determined gardener find sources for those difficult-to-find plants.

Ash Anthracnose

Cool and wet weather conditions in the spring are favorable for anthracnose fungi. Symptoms of ash anthracnose are beginning to appear. Infected leaflets often fall to the ground prematurely. A close look at the leaflets will reveal brown to black blotches. These spots commonly start at the margin and develop to the midvein. The leaflets tend to curl around the affected areas, causing a distorted appearance.

Images of ash anthracnose symptoms can be found on the Plant Disease Clinic website :

European Pine Sawflies Feeding Now

As you read this newsletter, European pine sawflies could be active in your landscape or Christmas tree plantation. On May 13, 2002, on the ISU campus, these larvae were1/2 inch long and had just started producing noticeable damage to mugho pines. Other favored hosts include Scots, red, and jack pines. Eastern white and Austrian pines are also fed upon when they occur in mixed plantings with favored species.

Ornamental Onions

Did you know that some onions have attractive flowers? There are several species of Allium or onion that are grown exclusively for their flowers instead of their bulbous structures. Ornamental onions (common name for many species) are not planted in the vegetable garden, but in beds or borders with other perennial flowers.