Resources for landscapes and gardens in the Midwest
A group of samples of several varieties of blue holly (Ilex x meservae) arrived in the lab from a commercial nursery in late January with a common problem, yellowing and rapidly dropping leaves and general poor growth (Fig. 1). After ruling out disease and insects on the foliage we next checked the root systems. After[Read More…]
Dandelion (Taraxacum officinale) Family: Asteraceae Life cycle: Perennial Reproduces: Seed Flowers: 1-2” diameter yellow disk and ray flowers on long stalk. Leaves: Simple, lobed (variable), wavy margins (variable), 3-10” long originating from a basal rosette Seedlings: Dicotyledon that is smooth, yellow-green and lack hairs. Comments: A very prominent tap root that can vegetatively[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…]
There may still be time to protect Prunus spp. from Taphrina leaf curl. Do you remember seeing red, curled, distorted, leaves on Prunus spp. last year and wondering what might have caused this symptom? Taphrina leaf curl, a fungal disease that survives in bark and bud scales, infects peaches and nectarines as well as ornamental[Read More…]
Spring provides a great opportunity to kill insects that winter in vulnerable stages on leafless twigs, or on last year’s hardened off evergreen leaves or needles. The absence of tender leaf tissue makes it possible to use higher concentrations of oil that can kill insects without harming the plant. Dormant oil applications can have the[Read More…]
Although late winter is generally the ideal time for pruning chores, many of our spring-blooming shrubs are best pruned immediately after flowers have faded. Trees and shrubs that bloom in early spring, such as forsythia, lilac, honeysuckle, quince and spirea, set their flower buds the previous fall, referred to as “flowering on old wood”. If[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…]
Although winter weather came late this year, when it finally arrived at the end of December, it was fiercely cold with temperatures dipping well below 0 ˚ F. Most Indiana insects can survive these temperatures. One serious defoliator, the evergreen bagworm may have been killed by the cold weather. What are bagworms? Bagworms, Thyridopteryx ephemeraeformis[Read More…]
The Perennial Plant Association (PPA) selected its 2018 Perennial Plant of the Year: Allium ‘Millenium’ (yes, that’s Millenium with just one n). This announcement continues to show the focus on pollinator habitat these days — Allium ‘Millenium’ is appropriately referred to as a butterfly and bee magnet! ‘Millenium’ is a hybrid Allium selected for late flowering.[Read More…]
This is the time of year when growers begin planting seed—whether you are child planting a few seeds in Dixie cup for a school project, home tomato growers, or professional horticulturists. Unfortunately, one problem you may share in common is damping-off. Damping-off describes the death of seeds or seedlings and includes all of the following[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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