What do I use to kill a stump? Its an elm that is about 5' across.

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

Drill some holes in the stump. Pour some buttermilk on it and it will deteriorate! Old school but it works!

Or a stump grinder, dynamite, lye? I still say buttermilk! Read this:

http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=ttalk&th=1482123  ; Good luck!

While the stump deteriorating, why not make a flower garden around it with some pots of flowers on top?

I would love to have such a stump in my yard! There are many ways to dress this up. Flowers, stones, paint,,,I'm sure Hometalk has addressed this issue before!

Cheapest most ecofriendly way is to use a hatchet make a cross hatch pattern (lots of 'em) and sprinkle with either table sale or rock salt and sit back and wait.

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.

Hello, 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/