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://www.purduelandscapereport.org/article/spotlight-on-weeds-henbit-lamium-amplexicaule/ Identification: Purple deadnettle is a winter annual meaning that it germinates in the fall, survives the winter as a small seedling, until spring when it flowers, develops seeds, and then dies when temperatures rise in late spring and early summer. Purple deadnettle blooms are mainly visible in April although you can find it blooming earlier and later depending on the area it is growing and the temperatures. Purple deadnettle is a member of the mint family and has a characteristic square stem. Purple deadnettle flowers are light purple in color and are small and tubular in[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 via broadleaf specific herbicides (Fig. 1), as well as grassy weeds can be controlled in broadleaf plants fairly easy with grass specific herbicides (Fig. 1 and Fig. 2). What is often misunderstood is the control of grassy weeds in grass-like ornamental plants. Broadleaf and grass weeds metabolize some herbicides differently. These differences allow herbicides to be selective in nature. True grasses are in the Poaceae family. Grass-like ornamental plants, such as liriope and iris are not in the Poaceae family, so the selectivity of grass-specific herbicides will not damage these plants. Grass-specific herbicides (called graminicides)[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 plant species (from the list of 44) if it is not already in Indiana. Listed plant species already in trade will be restricted from sale one year later (April 2020). The one-year grace period is designed to reduce the economic impact on the nursery industry by allowing time to sell down existing stock and adjust production.
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 let me know how to treat this damaged area so no further damage is done to it and tell me what can be done to preserve its longevity. I do not know the name of this tree but it’s local. It is found almost everywhere in this area. It blooms white flowers in the spring that fall off shortly after and changes to beautiful colors in the fall. As you can see, it is a beautiful tree. Please help and thank you so much. – L. G., Valparaiso, Indiana A: To answer the second part of[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 list the elements contained within, including the various types of nitrogen (Fig.1). What you should know about pH….. The definition of pH is the negative logarithmic of the hydrogen-ion concentration. What does this even mean? More simply put, the more H+ (hydrogen) ions, the more acidic, while the more OH– (hydroxide) the more basic. Always remember that the pH scale is logarithmic, which means each number on the scale is 10 times more acidic or basic than the next number on the scale. A pH of 6 is 10 times more acidic than a pH[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 now if one looks closely. Through a process called plant thermogenesis, heat is generated in the spadix of skunk cabbage. This allows the spadix, a flowering structure, to emerge from the cold ground, even through a blanket of snow, to claim the title as the first native plant to flower in the woods. Days later as the ground soaks up the sun’s warmth a plethora of spring ephemerals will blossom and convert a brown landscape into a colorful bouquet of floral delight. This is the time of year I most enjoy taking a walk through[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″ 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…]