It is easy to confuse Hemlock (Tsuga spp.) and Yew (Taxus spp.) unless you can see the overall plant habit or have them both side by side. Further confusing them is that both species may be pruned into hedges or other shapes that obscure the natural plant habits. Hemlock has short needles, 1/4 – 3/4″[Read More…]
Resources for landscapes and gardens in the Midwest
Landscape Report
Trees, Shrubs, Vines
A look back at the past year may help us be alert to problems ahead. Here’s a summary of the most common problems received in the diagnostic lab on woody ornamentals in 2018. As is typical for most years there were more non-disease (abiotic) problems than infectious (biotic) diseases found on PPDL lab samples in[Read More…]
The time is now to start protecting your trees! Now that your ears are perked up, let’s talk a bit about Southwest injury on trees. Bark cracking (Fig.1) is a phenomenon that occurs in many species of trees and can have many causes. One of the most common types of bark cracking is termed Southwest[Read More…]
The DNR Division of Entomology & Plant Pathology has discovered that a shipment of boxwood plants infected with boxwood blight was shipped to Indiana in May. This is important because boxwood blight (Calonectria pseudonaviculata) is a fungal disease that infests members of the popular Buxaceae family, and is often transported through the nursery trade. Hosts[Read More…]
Burning bush is so named for its brilliant red foliage display in autumn. But we sometimes get questions asking why their shrub fails to color up, with leaves that remain green until they drop from the plant. Fall color or lack thereof is affected by a number of factors, including genetics of the plant and[Read More…]
Bacterial leaf scorch (BLS) on oak is a systemic disease caused by the bacterium Xylella fastidiosa (Xf) (Fig 1). The bacteria live in the xylem vessels (water conducting elements) and restrict water flow. Xf is transmitted from tree to tree by xylem-feeding insects such as leafhoppers and treehoppers. Numerous woody hosts are susceptible to various[Read More…]
Although most “conifers” are “evergreen”, a few species are “deciduous”. Confused? Perhaps a review of these terms will help. conifer = cone-bearing evergreen = retains at least some green foliage year-round deciduous = all leaves die and are shed annually at same time Evergreens provide green color all year long but that doesn’t mean that[Read More…]
Boxwoods losing leaves should not be ignored!! Check them carefully for tell-tale symptoms of boxwood blight, a serious fungal disease that causes rapid defoliation and dieback (Fig. 1). The fungus that causes boxwood blight can infect all above ground portions of the shrub. The first symptoms of the disease are dark leaf spots (Fig. 2[Read More…]
An abiotic stress in plants is a stress due to a non-living factor, such as temperature, moisture, herbicides, etc. Biotic stress includes a living organism, such as a fungi, insect, etc. This series will explore some of the most common types of abiotic stress you may find in landscapes and nurseries. What is wrong[Read More…]
Getting calls from panicked customers about black spots on maple leaves? You’re probably not alone, because now is the time when people start to notice maple tar spot. Every summer we get questions about black spots on maple leaves that look like tar. These spots are not actually “tar” on maple, but are rather a[Read More…]
The Tree Care Industry Association (TCIA) conducted an analysis of 62 civilian tree care-related accidents reported by the media from January 2017 to June 2018. TCIA is a trade association that promotes professional tree care and discourages homeowners from taking unnecessary risks caring for their trees themselves. While these numbers are not representative of[Read More…]
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