Resources for landscapes and gardens in the Midwest
Landscape Report
Trees, Shrubs, Vines
Don’t miss the 2019 Purdue Turf and Landscape Field Day on July 9th! Your opportunity to interact with Purdue Specialists, see the latest on-going research and best management practices, and network with others in the Green Industry. This is the premiere Green Industry education event that you’ll find this summer! https://www.mrtf.org/event/turf-and-landscape-field-day/?event_date=2019-07-09 In the landscape track,[Read More…]
Although most cities contain an Elm Street, very few cities can claim having mature American elms on that street, or any other. The American elm was a premier street tree: Tolerant of compacted soil, fast growing, long-lived, and with a beautiful vase-shaped form. It’s very popularity led to its downfall. The introduction of Dutch elm[Read More…]
Like anthracnose diseases of other shade trees, sycamore anthracnose is a very common occurrence in the landscape (Figure 1). Symptoms of sycamore anthracnose normally develop as small spots or dead areas centered along the veins of leaves or along leaf margins (Figure 2). Under conducive conditions these spots expand, killing more leaf tissue and causing[Read More…]
Introduction The Colorado Blue spruce is not native to Indiana and tends to be susceptible to disease. One common disease, caused by the fungus Rizosphaera kalkhoffii, results in the defoliation of the tree. If left untreated needlecast can lead to the death of the tree. Symptoms and Signs Symptoms of needlecast don’t develop until two[Read More…]
Sudden oak death, as the name suggests, is a disease that is capable of rapidly killing certain species of oaks. It was first identified in California, in 1995. Two years earlier it was identified in Germany and the Netherlands, killing rhododendron. Because the pathogen originally infected and killed tanoaks, an undesirable, understory scrub tree, it[Read More…]
Although most people are understandably concerned about boxwood blight, boxwood does suffer from a number of diseases, including Volutella blight and Macrophoma leaf spot. Unfortunately, boxwood also suffers from a stem decline, caused by Colletotrichum theobromicola. The following was written by Dr. Raj Singh, LSU. Boxwood Stem Decline by Dr. Raj Singh Available on line[Read More…]
A question that I often receive goes something like…. ‘How do I control grassy weeds in liriope and iris?’ At first glance, it would appear that those ornamental plants are very similar to grasses, but looks may be deceiving as they are actually not grasses. We know that broadleaf weeds can be controlled in grasses[Read More…]
Oak leaf blister is caused by the fungus Taphrina caerulescens. Infections occur as buds swell and open during wet, spring conditions. Leaf blister symptoms usually appear within several weeks following infection as 1/4-1/2 inch circular, light green bulges on the top surface of leaves.(Fig 1) From the underside, the affected areas are sunken or depressed. These[Read More…]
Q: I’ve attached pictures of the only tree we have on our property. Because it is our only tree, I am deeply concerned with the possibilities of irreparable damage to it. As you can see, one of the branches broke off during a November windstorm. Unfortunately, that left a bare gap on the trunk. Please[Read More…]
We all know that plants take up nitrogen in significant quantities, compared to some of the other essential nutrients. What most don’t know is that elemental nitrogen (N) is not what is taken up by plants. In fact, nitrogen can be taken up in only two forms, ammonium (NH4) and nitrate (NO3). Fertilizer labels will[Read More…]
The Invasive Terrestrial Plant Rule was signed by Governor Holcomb and published on March 18, 2019. The rule goes into effect 30 days after publishing, so it will be effective later in April. The rule states with respect to the 44 plant species included on the rule: “a person must not: (1) Sell, offer or[Read More…]
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…]
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…]
Sign-up to receive email news and alerts from Purdue Landscape Working Group:
