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The ins and outs of Fall foliage

Elections and hurricanes and COVID – oh my! My family and I just took a much needed vacation to Tennessee, largely to relieve stress and stare at fall foliage for a while. On the return trip, my wife asked me why we don’t see such beautiful autumn color at home. It was a 10-hour drive, so she got the long version.

The short version centers mainly on two issues: We do not get the “snap” of cold like some other regions do but rather cool off gradually. The trees don’t get shocked into changing colors and dropping leaves in unison. The other point is that the trees we grow here are typically not the species that naturally produce such a show. Fortunately, there are several exceptions, and fall is a good time for planting trees in Louisiana.

One great native for color is the red maple or swamp maple, Acer rubrum. These trees consistently turn yellow, then quickly to red this time of year. (They also put on a spring show with red twigs, flowers and fruit / seed pods.) This is a fast-growing tree, and it commonly grows 50 feet tall or more.

As a native tree, red maple is typically low maintenance. Yes, it prefers well-drained, fertile soil. But it is tolerant of a wide range of soil pH, can grow in heavy clay soils and survives flooding. It is tolerant of poor soil drainage, a common problem for our area. Insect and disease problems are practically nil. As with all trees, keep grass and weeds away from the root zone and you’ve headed off most of your potential problems.

Though not native, Ginkgo biloba can provide us with fall color here as well. The leaves typically show a vibrant yellow in fall, then a little orange-y before dropping. To horticulturists and arborists, it’s especially interesting: It’s a gymnosperm (like pines) but has broad leaves that drop seasonally. It’s also considered a “living fossil” because its species is so old. Actual fossils of it have been found in the range of 100 million years old.

They’re not very fast growing but ginkgos do thrive in our area due to features similar to our natives (tolerance of heavy soils, etc.) The trees are dioecious; that is, individuals will be male or female. You’ll only find grafted males sold at nurseries, as females produce a yucky fruit that would make a mess of your lawn.

Finally, I’d like to recognize the golden raintree, Koelreuteria paniculate. Besides Google

Images, you can see a wild (invasive?) copse of these on the north side of Airline Highway just east of the Bonnet Carré Spillway. Right now they’re recognizable by their yellow and red foliage, but also by lots of seed pods that look like pink flowers. (The actual flowers are yellow and hang in long panicles.)

Like the previous two, they grow well here and tolerate a wide range of conditions. They are native to China and are pretty fast growing. They’ll reach 30 to 40 feet mature height with pointed compound leaves that are reminiscent of pecan. You won’t find them in nurseries that I know of but they propagate readily from those lovely pink seed pods.

 

If you want to know more about gardening, landscaping, or anything else horticultural, contact the St. John & St. James Parishes County Agent André Brock at abrock@agcenter.lsu.edu . Also, the LSU Ag Center’s website can be accessed at www.lsuagcenter.com with lots of user-friendly information, including this article.