Ask Mr. Smarty Plants

Now you know one of the reasons the Lady Bird Johnson Wildflower Center recommends only plants native not only to North America but to the area in which they are being grown. Lagerstroemia indica, (crapemyrtle) is native to temperate and tropical Asia, including, among others, China, Bangladesh, and Nepal. We have heard many complaints about the messiness of the plant, the sap dripping onto cars and people (usually because the tree is infested with aphids), and, of course, its invasiveness, which is what you are experiencing. We frankly had never tried pouring diesel into a stump to kill it, glad you survived the experience, and it appears the roots survived, too. Here is what we suggest for getting rid of a plant that won't go away voluntarily. We don't like to recommend herbicides, but this is an extreme case. Get a small bottle of glyphosate systemic herbicide, which is sold under several brand names. Get some disposable paintbrushes. Now, try to trim some more off the stump, all the way across, and paint that new area, right away, with the herbicide. You need to do it quickly, because within 5 minutes the tree (which obviously still has live roots) will be healing itself over to prevent the entry of that herbicide into the root system. Each time a new shoot comes up, either cut it and paint it with more of the herbicide, or try to dig it out down to the root. The root has a lot of nutrients stored up in it and is one of the survival tactics of plants, but the roots also need leaves to get the sunshine for photosynthesis and manufacture more food. It will take some time and patience but eventually the roots will starve and give up and die. You may also be experiencing some seedlings coming up; remember those ugly seed pods all over the tree? Pull those out while they are still small enough to get roots and all.

And, above all-be careful with that herbicide! Don't let it get on the ground if you can help it, and don't spray. You don't want to contaminate the soil where you will probably wish to plant something else (if the diesel hasn't already done so), and you sure don't want spray drift to damage some plants you already have.