Roots, Shoots, Fruits & Flowers: Drought-stressed Trees, Persimmon Seedling, Lichens & Sweetbay Magnolia

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Irrigation of a tree. Photo: extension. missouri.edu.

Drought-stressed Trees

Lillie asked about her oak trees via email, “I have two oak trees that are dying and have counted numerous one in my travels. Do you have any idea what is going on?” A little later, Shannon asked, “Our [crape myrtle] tree has tons of leaves turning yellow and falling off. Is drought the cause?”

The short answer is “yes” to Shannon’s question. Lillie’s trees are suffering from drought stress, too. AHA added this comment and recommendation, “We are about fifteen inches behind in rainfall [for July 2022], and like you, myself and others are seeing trees succumbing to drought stress. Let me encourage you to use a soaker hose to irrigate your oak trees. Your trees need an inch of water per week. With a soaker hose, place the squarest pan you have under a section of the hose, and then measure the depth of water to see if you are reaching your one-inch threshold.”

The trees with brown leaves attached have succumbed to the drought while the tree with yellowing and falling leaves are likely to have gone into dormancy earlier than usual and will probably leaf out again next spring.

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A persimmon seedling. Photo: Silas Cecil, LSU AgCenter

Persimmon Seedling

Silas Cecil, a 4-H agent in LaSalle Parish, sent an email asking for ID of suspect weed, “One of the deputies asked about the below weed growing in his yard. Says after mowing it comes back. I have the same thing in patches in my yard as well.”

The plant in Silas’ image is persimmon seedling, and it may be a weed if it is unwanted. Or it could be a new fruit tree in the yard. Dr. Heather Kirk-Ballard wrote a Get it Growing article titled Persimmon: the other orange fall fruit. She describes the several types of persimmons, either native or Asian, and the best growing conditions. She also looks at the uses of these persimmons, “Fruits can be made into jellies, jams, marmalade, and syrups. Or just grab a ripened fruit and eat them whole or slice them. They are particularly yummy in salads, and the leaves can be brewed to make tea.”

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Several types of lichens. Photo: Ashleigh Midkiff, LSU AgCenter.

Lichens

Ashleigh Midkiff at the AgCenter in Vernon Parish sent an email and image on behalf of a homeowner, “Mr. William came in and wanted to know how to get rid of this growth on his trees.”

Mr. William is among the citizens who repeatedly ask about lichens and their treatment. Homeowners are often concerned when they see lichens. However, Dr. Raj Singh, a plant pathologist, wrote this line in the Lichens factsheet, “So the question is: Are lichens plant pathogens? And the answer is: No! Lichens are not plant pathogens. They use a tree or another surface as a substrate to grow epiphytically [and derives its moisture and nutrients from the air, rain…]. Lichens are not parasites and do not derive any nutrients from the host they are growing on. Lichens may grow on healthy as well as stressed trees. They are more noticeable on stressed trees because of the open or thinner canopy.”

If your tree’s canopy is thin during the growing season and if you can see the lichens easily, then your tree is having other issues, perhaps related to fertilization, drought, root damage, etc.

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Sweetbay magnolia Photo: Dennis Gibson.

Sweetbay Magnolia

Dennis sent an artistic image and wanted to identify his tree. Dennis has a sweetbay magnolia, a native tree. Dan Gill, retired AgCenter horticulture specialist, wrote about this tree, “The evergreen sweetbay magnolia reliably retains its foliage during winter. This naturally occurring variety is distinct from the standard species, Magnolia virginiana, for this reason. The standard species is deciduous to semi-deciduous and drops most or all its leaves during winter. The evergreen form grows in the most southern parts of this species’ natural range in the eastern U.S.”

“The flowers also make this tree popular. They are creamy white and about 2-3 inches in diameter. Flowers generally appear in greatest abundance beginning in late April, peaking in May, and diminishing in early June. But flowering may continue sporadically through the summer. They are not as large and showy as the flowers of Southern magnolias, but they have the same rich, lemony fragrance that many Louisiana gardeners know and love so well.”

If you want to contact Roots, Shoots, Fruits, and Flowers, please send your questions and pictures to Keith Hawkins, Area Horticulture Agent (AHA), 337.284.5188 or khawkins@agcenter.lsu.edu.

“Before you buy or use an insecticide product, first read the label, and strictly follow label recommendations. Mention of trade names or commercial products in this article is for informational purposes only and does not constitute endorsement by Louisiana State University AgCenter.”

“This work has been supported, in part, by the USDA National Institute of Food and Agriculture, Renewable Resources Extension Act Award, Accession Number 1011417.”

8/9/2022 7:12:28 PM
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