Tree in the built environment often need supplemental nutrition to improve growth and resist pests. Fall fertilization can help trees get off to a healthy start next growing season.
Trees, Shrubs, Vines
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 about Bacterial Leaf Scorch of Oak: Lab Confirmation Necessary[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 about Even Evergreen Needles Don’t Last Forever[Read More]
Oak wilt has been found in most counties in Indiana and is one of the most serious threats to the health of oak trees in the Midwest, especially those in the red oak / black oak group. The disease is caused by the fungus Ceratocystis fagacearum and is spread from tree to tree by sap…Read more about Oak Wilt in Indiana[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 about Boxwood Blight – Be on the Look-Out[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 about Common Abiotic Problems of Ornamentals: Soil pH Effects on Fertility[Read More]
Q. We have a large sycamore tree in our yard. Every summer it sheds its bark over a few weeks’ time. I think as it grows it is growing new bark and losing the old bark. Am I correct? – J.C., Walton, Ind. A. You’re on the right track. Peeling bark is normal, and is a key…Read more about Peeling Sycamore Tree Bark is Normal[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 about Tar Spot on Maple[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 about Homeowner Tree Care Accidents[Read More]
Most landscape professionals and gardeners have heard of the wise advice “leaves of three, let it be” referring to the pest plant poison ivy. While not quite as catchy, the saying really should be “leaflets of three, let it be.” Poison ivy leaves are compound rather than simple – a single leaf is divided into…Read more about Poison Ivy[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. We’ve all experienced the…Read more about Common Abiotic Problems of Ornamentals: Transplant Shock[Read More]
One of the most common problems of broadleaf shade trees is a group of diseases collectively known as anthracnose. Anthracnose diseases are caused by fungi and become severe when cool, wet spring weather persists as leaves are first emerging. The most commonly affected trees are ash, white oak, maple, and sycamore. Dogwood, birch, elm, walnut,…Read more about Anthracnose of Shade Trees[Read More]
This article, and many others, will be presented at the 2018 Purdue Turf and Landscape Field Day on July 10th. Registration is open and available online: https://www.mrtf.org/event/turf-and-landscape-field-day/?event_date=2018-07-10 Here is the lineup for the field day. A cultural weed control method is one that involves steps to reduce or eliminate weeds via maintenance techniques. In landscapes, the…Read more about Cultural Plus Chemical=A good weed control combo in landscape beds[Read More]
The Purdue Plant and Pest Diagnostic Lab (PPDL) recently received samples of Mugo Pine and Spruce that exhibited reddish-brown bands on needles of lower branches (Figs 1 & 2). Microscopic examination of needles confirmed the presence of Dothistroma,(Fig 3) a fungus that causes red band needle blight. Needles infected with Dothistroma first exhibit dark green…Read more about Red Band (Dothistroma) Needle Blight[Read More]
Arborvitae varieties (Thuja spp.) provide some of our most beautiful and versatile evergreens for landscapes, with an extensive selection of sizes and types. Unless they get proper care, they also give us some frustrating failures. Here is my list of the most frequently encountered ‘Arborvitae Aggravations’, based on the samples and questions we get in…Read more about Top Arborvitae Aggravations[Read More]
