Roots, Shoots, Fruits & Flowers: Goat’s Rue, Sick Spruce, Happy Mayhaw & Algal Leaf Spots

515_fig_1_wildflowerjpgGoat's Rue, a wildflower in the pea family. Photo: Tim Cooper.

Goat's Rue

Tim C., a professional consulting forester, found this wildflower and wanted to have it identified:

Tim’s plant is called “goat’s rue”. According to the North Carolina State Extension webpage, it is a native plant in the pea family, so it is a legume. It is poisonous for people, insects, and fish. However, its flowers are suitable for butterfly gardening. It prefers dry, open woodlands and needs full sun, and it is difficult to transplant if you want this plant in your landscape.

515_fig_2_Colorado_blue_sprucejpgColorado blue spruce with fungal disease, cytospora canker. Photo: unknown.

Sick Spruce

AHA received an unusual email about a tree in another state, and it represented a professional challenge. Johnnie sent an email and some pictures, “I am sending you 3 pictures sent to me by a relative in Arlington, Virginia. They asked me if I knew why their trees were dying. They said they start dying from the bottom and move up the tree. Not sure exactly what kind of tree, but all 3 are the same. All I see is [that the] mulch [is]too high. Would you have any idea why they are dying?”

This tree is a Colorado blue spruce, and this tree grows best in cooler climates. The Virginia Cooperative Extension reports that, in warm locations, it become stressed and susceptible to a fungal disease, cytospora. The disease starts at the bottom of the trunk like in the image, and then progresses up the tree. The good news for Louisiana gardeners is there is no known cytospora diseases actively attacking trees in our landscape. However, if you suspect this disease in your evergreen trees, then contact the LSU AgCenter in your parish.


A happy mayhaw loaded with fruit. Photo: Brent McFatter.

Mayhaw loaded with fruit

Most of the time, RSFF readers send pictures and questions about problems and challenges. Brent shared an unusually pleasant image of a happy mayhaw tree loaded with fruit.

All Brent wanted to say with some pride in his email, “Good season.” Congratulations on the plentiful mayhaw yield!


Leaves from a southern magnolia with algal leaf spot. Photo: Joe Miller, Master Gardener.

Southern magnolia with algal leaf spot

Joe, one our gardening friends from Newton, TX, sent a picture of an infected magnolia leaf and wants to know more about this condition.

In an issue of the GNO Gardening, Anna Timmerman, an AgCenter horticulture agent in the New Orleans area writes about algal leaf spot, “In Louisiana, these algae can be found on the leaves of plants that have a leathery texture: Camellias, magnolias, holly, Indian hawthorn, and avocado. Luckily, in our area these algae do little harm other than making unsightly spots on the leaves of these plants.” The surplus rain this spring enabled algal leaf spot to occur on Joe’s magnolia.

If you want to contact Roots, Shoots, Fruits and Flowers, please send your questions and pictures to Keith Hawkins, Area Horticulture Agent (AHA), 337-463-7006 or Also, you can be on the “green thumbs” email list by emailing your request to the address above.

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

5/20/2020 8:29:51 PM
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