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…]
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Landscape Report
Trees, Shrubs, Vines
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…]
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…]
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…]
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…]
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…]
Translated by: Dania Rivera, Ornamental Horticulture Extension Specialist, University of Puerto Rico “El mejor momento para sembrar un árbol es veinte años atrás. El segundo mejor momento es ahora” Anónimo Si vas a hacer algo, hazlo correctamente la primera vez. Esto es cierto para muchos aspectos de la vida, pero, cuando se refiere a la[Read More…]
Three different rust fungi cause gall-like protrusions on eastern red cedar (Juniperus virginiana) trees. The bright orange gelatinous galls with tendril-like protrusions (Fig 1) resembling ‘koosh balls’ are caused by Gymnosporangium juniperi-virginianae. This fungal disease is known as Cedar Apple Rust. The galls develop on the cedar tree (Fig 2) and ‘sprout’ fungal spore-bearing tendrils during[Read More…]
Purdue’s Plant and Pest Diagnostic Lab (PPDL) receives more than 2000 samples for diagnosis each year. We’ll highlight some of the more interesting cases in the Purdue Landscape Report in brief case studies like this. PPDL Case Study #1: White Fungi on Crabapple Branch Earlier this year a landscaper submitted several photos of a crabapple[Read More…]
It’s that time of the year. Starting in the southern portions of the state and gradually moving north, trees, shrubs, and flowers are beginning to break bud, showing the flowers that have been protected all winter long. One of the first trees that you will notice, increasingly out of place more each year, is callery[Read More…]
Winter of 2017-18 was pretty harsh compared to most years. Much of central and northern Indiana experienced 13 or more days well below 0º F, while southern Indiana had 4- 5 days just a few degrees below 0º F. In addition, gusty winds contributed to further injury by desiccation of buds and twigs. The consequences[Read More…]
Colorado blue spruce is not native to Indiana (no spruce is!), and it often suffers from environmental stresses such as drought, excessive heat, humidity, and compacted or heavy clay soils—making it an already poor choice for our landscape. If that weren’t enough, it also suffers from needle cast diseases. Needle cast is a generic term[Read More…]
Fill in the blank: Apply crabgrass preemergence herbicide when____________is in bloom. If you said forsythia, you would be correct. Most of us have been told the answer to this for many years, but have you ever thought to yourself, ‘Is it true?’ There are many ways that people make decisions on when to apply herbicides. [Read More…]
Finding a qualified tree service is important protection for the tree owner. Often, less credible tree companies follow storms for a “quick buck” and move out of town as fast as the storm. Knowing how to hire a reputable arborist can help prevent becoming a victim all over again. A professionally trained arborist can help[Read More…]
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