How do you kill tree roots/stump

Make holes in the bark and use stump out

There's a poison that looks/smells like creosote that you can use by drilling a hole in the root and pouring in about a teaspoon. Ask for it at Ag coops.

drill big holes down in to the trunk then fill with rock salt

I drill a 1/4 hole in the stump and put a tablespoon of Roundup in the hole. You can buy products to kill stumps but I use the Roundup because I have it. Key is to expose some living tissue so the chemical can be absorbed.

Drill 1/2" holes in the stump or roots as deep as possible, don't go all the way threw if drilling in a root, then fill the holes with Epson Salt, add a little water but not enough to run out of the hole.

Well, I wish I had that crape myrtle. lol! But since you've done it, there are several stump killers available at garden centers. Most require you to bore holes and pour the stuff in. It takes several months to complete the process but it will totally rot them away. Just this year, I have eliminated Burford Holly (3 of them), those awful prickly shrubs someone planted here years ago. And, like you, I have green shoots showing they're determination. Don't we wish the plants we love have that much resiliency? I am using something called 'Green Light Stump Remover'. I have used it before and it works.

Here are several methods you can try

http://m.wikihow.com/Kill-a-Tree-Stump

Also , there is an enzyme you can find at Home Depot that will help disolve the roots and stump.

try white vinegar and pour on the stumps. It should help kill the foliage and keep it from growing

Drill 1/2 inch holes in the stump and fill it with rock salt. Vinegar or mineral spirits work also.

Thank you all for taking time to answer. I will try these ideas.

Use this product and you should have success. Bonide

Begin by gathering a few supplies: a drill with a large bit or an ax, Epsom salt, water, wax, a tarp, and a shovel. Proceed to drill several 1-inch-wide holes in the stump's surface, including its aerial roots, ensuring each hole is placed at a distance of at least three to four inches. While six holes are sufficient, bigger stumps may require more. Ensure you drill down to around eight inches to allow for deeper salt penetration. Alternatively, you may use an ax to make hollows in the tree stump. Next, directly pour Epsom salt ¾ of the way up in the drilled holes and fill the rest with water to keep the salt moist. Then, plug the holes with wax. Additionally, cover the trunk remnant with a non-porous tarp to minimize rain and sun exposure so that the roots do not sprout again and the salt does its job of rotting the stump. Repeat the procedure every three weeks until the stump is dead, and dig it out using a shovel.

If you don't wish to strain yourself by drilling holes, you can use the soaking method to remove a tree stump. In a bucket, combine Epsom salt and water in a 1:2 ratio. Generally, soaking a single tree base requires two gallons of water and one gallon of salt. Pour this solution all over the tree stump and its largest exposed roots. After drenching the stump, cover it with an opaque tarp or a plastic sheet, and add a layer of mulch on top to weigh it down. You can also sprinkle a nitrogen-rich fertilizer around the tree trunk's base to further boost its breakdown. Repeat this method at least once a week and chip away at the wood as it decomposes. Finally, pull out all the stump remnants, especially the root system, when it completely dries out. After disposing of the stump, you can repurpose the space by adding soil and sowing grass or flower seeds.

Hi Donna, hope this helps you. Drilling holes into the stump will help the hot water kill deep and exposed roots. After you're finished drilling, carefully pour boiling water over the stump, making sure to cover the entire stump. The hot water will shock the system and begin the decomposition process using heat. Then you could pour some epsom salts in the holes and cover them ( to prevent them getting diluted by rain)to let them break down the stump.

Epsom salts

https://www.bobvila.com/articles/how-to-kill-tree-stumps/