Prickly pear cactus

Frederick County has a wide diversity of plant species, including a member of the cactus family, the Eastern prickly pear cactus. There are nearly 200 species of prickly pear cacti found in the United States. This is the most cold hardy, found as far north as Canada. The Eastern prickly pear prefers drier ground and direct sunlight, very much like desert conditions. It is often found in shale barrens in Western Maryland.

It has a yellow flower that blooms in late June and early July, and a red edible fruit often used in jams. To get to the fruit, carefully peel the outer spiny skin. Many species of this cactus are also used for home remedies, a refreshing drink and alcoholic beverages.

Prickly pear cacti growing near the Monocacy in Frederick County

Photos by Mike Kay

Fungus among us

In contrast to a dry August, most of the early 2008 growing season was characterized by cool, moist conditions. This type of weather often aids the development of various diseases that can affect trees and other plants.

Anthracnose

A common fungal disease currently impacting a number of trees in the county is anthracnose. There are species of anthracnose that impact many trees, including oaks, walnut, ash, sycamore, elm and dogwoods. Anthracnose normally shows first as a rectangular brown blotch on the leaf. As it progresses, leaf blotches merge together turning the leaf brown, sometimes causing the leaf to fall. In severe cases, the anthracnose may result in premature dropping of all leaves, which could impact the health of the tree. On rare occasions it could result in the death of the tree.

Anthracnose affects different species in different ways. Sycamore trees were late in leafing because of anthracnose. In dogwoods, it can result in leaf drop, dieback of branches and development of large basal cankers that eventually kill the tree. Populations of wild dogwoods in the forests have been damaged greatly by anthracnose over the last 20 years, particularly in the mountainous regions of the county.

Anthracnose causes a blotchy appearance on the leaf. Here the anthracnose is on a black walnut

Photo by Mike Kay

Nature Note for 9/14/2008