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″ long, green above and distinctly whitish silver below due to prominent white stomatal bands. Cones are 1/2 – 1″ long, ovoid, and pendulous. Yew has a slightly longer and wider needle -about 1/2 – 1 1/4″ long, dark green above and light green below, overall coarser texture compared to hemlock. Cones resemble berries, the brown seeds are covered by a fleshy red aril (seedcoat).
The time is now to start protecting your trees! Now that your ears are perked up, let’s talk a bit about Southwest injury on trees. Bark cracking (Fig.1) is a phenomenon that occurs in many species of trees and can have many causes. One of the most common types of bark cracking is termed Southwest injury. Southwest injury occurs during the winter months on the lower section of the trunk on the southwest side. This happens when there is a sudden temperature drop, for example, the sun going behind a cloud during the winter. The freeze-thaw cycle happens very quickly when there is a change from very warm to cold conditions, which results in a crack. If there is a snow pack, the reflection of sunlight on the bark will actually increase the temperature in the bark (Fig.2). Usually Southwest injury occurs on thin-barked trees, such as Acer spp., Cercis spp., Malus spp.,[Read More…]
Burning bush is so named for its brilliant red foliage display in autumn. But we sometimes get questions asking why their shrub fails to color up, with leaves that remain green until they drop from the plant. Fall color or lack thereof is affected by a number of factors, including genetics of the plant and environmental conditions such as temperature, soil moisture, nutrition, and sunlight. If a particular specimen fails to perform over multiple years it is likely that the plant lacks the genetic disposition for good fall color. This is not likely to improve over time. Burning bush, also known as firebush, is considered an invasive plant in many states and is listed as a medium threat on the Indiana Invasive Species Council invasive plant list. https://www.entm.purdue.edu/iisc/invasiveplants.html This could be an opportunity to consider replacing burning bush with one or more of the following alternative shrubs with attractive fall[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 with this maple? How would you correct the problem? If you guessed manganese deficiency, you would be correct. In areas with high pH, such as many locations in the Midwest, manganese (Mn) deficiency in maple is very common. When the pH of the soil is above 7, manganese is not readily available to the plant, even if there are sufficient amounts of manganese in the soil. As the pH of the soil increases, manganese is less and less available. We tend to begin seeing manganese deficiency when the pH is above 6.3 (Fig. 1). [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 ornamental characteristic for a sycamore, also known as American planetree. The bark starts out a bit gray-brown and as the bark matures, the outer layer peels off in large sheets to reveal a lighter-colored, creamy, off-white inner layer. The result appears a bit like a camouflage pattern. No need to worry – the tree is not harmed by the peeling bark.
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 three separate portions, called leaflets. Plants with three leaflets are often referred to as being trifoliate. Another key identifying characteristic is that one side of a leaflet may have an irregularly toothed margin, while the opposite edge may be smooth or barely toothed. Poison ivy is typically a vine that can climb quite high by means of aerial rootlets. But older poison ivy plants, especially those that have been cut back repeatedly, can take the form of a shrub. Poison ivy flowers are rather inconspicuous and usually not noticed by gardeners. The subsequent fruits are[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 problem. Sometimes it’s barely noticeable, and other times it results in death. Even if you don’t notice, it most likely still occurred. Environmental conditions can be helpful, or quite the opposite. Of course, we are speaking of transplant shock. Transplant shock occurs when plants become stressed due to poor root establishment, often mimicking drought stress. The severity of transplant shock is dependent on many factors, which include plant species, soil type/quality, moisture, temperature, growth stage of the plant, root loss from the nursery, as well as many other factors. If transpiration rate (loss of water[Read More…]
Gypsy moth has many homeowners scrambling to deal with large caterpillars stripping leaves from their trees. Don’t panic! We explain how to manage it.
People often select plants first for their beauty and second for their functionality in the garden. Frequently, we don’t know or don’t consider a plant’s behavior when we’re selecting them. Almost by definition, a species that is an effective ground cover will have a spreading habit. But does that make the species aggressive or invasive? There can be much confusion about the meaning of the terms aggressive and invasive. Some plants, given their optimal habitat, can become quite prolific in the garden. A plant can be considered aggressive if it spreads and has the potential to take over a garden area. However, some planting sites may call for an aggressive habit. A spreading plant can be considered invasive if it can also escape the garden setting and move into natural areas (prairies, wetlands, and so on) and displace native vegetation. Truly invasive plants have the potential to dominate natural vegetation.[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 most common type of cultural control is mulching. Mulching provides many benefits in the landscape, including moisture retention, temperature consistency of the root zone, improvement of soil structure, addition of organic matter, aesthetics, and, perhaps most important, a significant reduction in weeds. Mulch prevents weeds a couple of different ways. Many weed species require sunlight for germination to occur. By shading the soil beneath the mulch, weed seeds that require sunlight will not begin to germinate. The other way that mulch prevents weeds from germinating is by providing large air spaces (macropores) between the pieces[Read More…]