Observation of the Crape Myrtle (Lagerstroemia indica)

Davor Ivkovic

For my Travis County Almanac environmental research, I have decided to focus on an organism that I have been seeing for more than three years now, but I haven’t stopped next to it, took a closer look at it, and enjoyed its beauty until this semester. The organism I’ve decided to observe and study throughout this semester is Lagerstroemia indica, commonly known as Crape Myrtle. This genus of trees is often referred to as the “lilac of the South”. This tree is located on a very beautiful and green area of the St. Edward’s University campus, next to the tennis courts. During the first 6 weeks of observation, I have seen some extremely interesting things going on. In the area around it, I found the same exact trees, however I realized there are some interesting differences between the tree I was observing and the other ones. During our hike to the Blunn Creek Preserve, I expected to see more trees of this kind, but surprisingly I haven’t seen any Crape Myrtle around.

Flowers on the Crape Myrtle

Other Crape Myrtles in a very close area (interestingly, not having any flowers)

Distribution of Crape Myrtle in the US

 

Crape Myrtle is a genus of around 50 species of an upright, wide-spreading, deciduous shrub or small tree in the loosestrife family Lythraceae. It is native to the Himalayas through southern China, Southeast Asia, and Japan. They were introduced into North America in 1700s, and are distributed in the warmer parts of the United States, specifically in the south and southeastern states (Arbor Day Foundation, 2017). They are known for their colorful and long-lasting flowers which occur in summer. They are generally producing diverse colored flowers in summer and early fall. Colors vary from deep purple to red to white, with almost every shade in between. Crape Myrtle is among the longest-blooming shrubs and small trees, going up to 120 days per year. They are one of toughest, most adaptable, and showiest plants that can be grown on Texas landscapes, so it is not surprising that state of Texas designated Lagerstroemia indica as the state shrub in 1997. Crape Myrtles “can take all the heat our summers here in central Texas can dish out without so much as a whimper” (Richter, 2013).

Full size of Crape Myrtle (about 20 feet tall)

Appearance of ball moss on Crape Myrtle

So far, after 5 weeks of observing, I have seen some changes in the color of the flowers. At the beginning of September, the flowers were light pink; however, one month later, at the beginning of October, I realized that the flowers were more deep purple. Furthermore, the amount of ball moss increased over the period of one month, and now there are a lot of them as it can be seen on the photo provided. One specific branch that I took a photo of was intriguing. It can be seen that the flowers have died and that there is a lot of spider web on it. There is a big chance that spiders, beetles and other animal activity have negatively affected it. A very common problem that Crape Myrtle usually has is “sooty mold”. I believe that this disease affected some part of the tree I am observing. The study from Clemson University about Crape Myrtle diseases shows that when sooty mold shows up “Leaf and stem surfaces are covered with a black sooty substance, causing them to appear black and dirty. Sooty mold indicates that there is an insect problem on the plant” (Crape Myrtle Diseases & Insect Pests, 2002). This explanation draws me to conclusion that there is an insect problem on the tree. I have mentioned before that there are same kind of trees in the area around. What I thought was extremely interesting is that that on all other Crape Myrtles around, the flowers are completely gone. I find this interesting because all of the trees are about the same size, and get the same amount of sun. It might be that aphids are attacking these trees, considering that “they feed on the leaf sap and excrete a sticky substance known as “honeydew”, quite a pleasant name considering its origin! The honeydew falls onto the leaves below and supports the growth of a black sooty mold” (Richter, 2013). This observation tells me that there is a big possibility that some disease is attacking Crape Myrtles in the area, however, the one that I am observing is still blooming and stands out.

Dying flowers with the spider web around, looking like “sooty mold”


Out of all trees I pass next to while walking on the beautiful St. Edward’s University campus, this Crape Myrtle is absolutely the most stunning one, especially because of the beautiful changing colours of its flowers. It is very unique, I haven’t seen more beautiful colours around the campus, therefore it will definitely catch the eye of every passer-by. I am extremely excited to continue observing the temporal patterns of this Crape Myrtle, especially because the cold period is coming soon, so I really want to see how it will “take” the cold weather, for how long are those beautiful flowers going to last, and whether the disease that is attacking surrounding trees is going to catch this one as well.

 

Bibliography

Arbor Day Foundation. (2017). Crapemyrtle (Crape Myrtle) – Lagerstroemia indica. Retrieved October 10, 2017, from https://www.arborday.org/trees/treeguide/TreeDetail.cfm?ItemID=824

Crape Myrtle Diseases & Insect Pests. (2002). The Clemson University Cooperative Extension Service. Retrieved October 09, 2017, from http://www.clemson.edu/extension/hgic/pests/pdf/hgic2002.pdf

Richter, S. (2013). Crape Myrtles for Central Texas Landscapes. Texas A&M AgriLife Extension. Retrieved October 10, 2017, from http://aggie-horticulture.tamu.edu/travis/wp-content/uploads/2013/06/Skip-Crepe-Myrtles.pdf