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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 about Needlecast in Colorado Blue Spruce[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 about **SPECIAL ALERT** Sudden Oak Death[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 about Other Boxwood Issues[Read More]



Biology: Purple deadnettle (Lamium purpureum) is a common winter annual broadleaf weed found throughout the US. It is closely related to another winter annual broadleaf, henbit (Lamium amplexicaule). Both have vibrant purple flowers that can been seen now in lawns, landscapes, and fields.  To see more about henbit, refer to this article from last spring: https://purduelandscapereport.org///article/spotlight-on-weeds-henbit-lamium-amplexicaule/…Read more about Spotlight on Weeds: Purple deadnettle[Read More]



Hosta Virus X (HVX) is not a new problem, however, it’s not as prevalent as it was nearly a decade ago because growers have gotten better about recognizing the disease and removing infected plants from their nurseries. The most common symptoms include mottled, light or dark green discolorations along leaf veins (Fig 1). HVX may…Read more about Hosta Virus X[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 about Killing Grasses in ‘Grasses’? How to control grasses in non-grassy ornamental plants[Read More]


A new publication for nursery growers has been released!  This publication, a joint venture between Purdue University and Indiana Department of Natural Resources, informs that nursery and landscape industry about new state regulations regarding invasive plants.  The rule goes into effect in two stages. As of April 18, 2019, it is illegal to introduce a…Read more about What Nurseries Need to Know About the Invasive Species Regulation? New Publication for Nursery Growers[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 about Oak Leaf Blister – No Cause for Concern[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 about Ornamental Pear Fallout[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 about Changing pH and Fertilizing at the Same Time? How nitrogen sources can change soil pH[Read More]



Hakone grass (Hakonechloa macra), also known as Japanese forest grass, is often used for massing in beds in where a low maintenance ground cover is needed in semi-shaded areas. The graceful arching stems along with the availability of gold or white striped variegated cultivars make it an attractive option. There are few reports of disease…Read more about Gray leaf spot/blight of Hakone Grass[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 about Terrestrial Invasive Species Rule Signed by Indiana Governor[Read More]


As I type this article, the outside thermometer is showing 10 degrees F.  Ouch!  And the calendar reads March 4.  Double ouch!  Winter is stubbornly hanging around for a few more days, maybe weeks.  Eventually, the dreary cold weather will surrender to spring and life will return to the woods.  However, subtle changes are occurring…Read more about Early Spring in the Woods[Read More]



Volutella stem and leaf blight, caused by the fungal pathogen Coccinonectria pachysandricola (=Volutella pachysandricola),  can cause major damage to Pachysandra – destroying large areas in a bed. (Fig 1)  Infected leaves first develop tan or brown blotches with dark brown margins, which expand, often with concentric lighter and darker target-like zones. (Figs 2a,b) Stem and…Read more about Volutella leaf blight and stem canker of pachysandra[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 about Distinguishing Hemlock from Yew[Read More]


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