Not all sumacs are alike, not all sumacs spread (the rope-like roots of those that do are called "ryhzomes"), and those that spread are a gardener's nightmare. I have only come up with one proven solution to getting rid of them, and that is by digging up and removing every single inch of rhyzomes by hand. This has been proven in Eastern Canada and the USA where sumacs are an invasive species. Roundup only kills the plant above ground; ditto for burning. Cutting (eg using a lawnmower) encourages spreading. Rototilling spreads the pieces of rhyzomes around where they will take root happily. There IS a herbicide that must be applied to the rhyzomes that will kill them, but since you have to dig them up to do so, you might as well just remove them. That herbicide is only legal for use in Canada by trained and licenced users, not the average gardener. It can be obtained in the USA, but as already said, you have to dig up the rhyzomes to paint them with it, so you might as well just remove them and not bother with the applicating of the herbicide. If you don't remove the parent plants, they will of course send out new babies to replace all you've dug up… Since the rhyzomes can go more than 2' deep, I doubt a root barrier would stop the spread. I am personally dealing with this exact situation right now. It is said that it takes 3 years of careful digging (removing bits you missed the previous year), to remove everything. So this is not a quick and easy project you must undertake. People will be happy to dish out free advice on this, when they see you on yours hands and knees digging, but virtually no one has any advice that is worth trying. Kneel and dig is your ONLY viable option. For three thorough, consecutive years. Tough if you have arthritis anywhere… All the best. In the picture below, I have dug up rhyzomes on the right side, just to the left of the Maple tree in the middle. The orange flags indicate where I left off, and areas to be watched for regrowth, or rhyzomes that go deeper than 2'. There are 2 adult sumacs on the left of the house. The original parent plants died long ago, and I eventually cut them down. So I'm sure the existing 2 adults are now sending out lots of rhyzomes… There are sproutings in the next door neighbour's property, so unless I put in a root barrier, and it WORKS, the rhyzomes with just come back from his property. And no, he won't bother digging them up. The lawnmower technique is the most he'll do… file://localhost/Volumes/LEXAR/DCIM/101ND300/DTC_8768.JPG

Vaherbmom THANK YOU!! meldy_nva Pine-Sol! The smell is overpowering but makes so much sense!! I was going to run a hose about 10’ into their hole and funnel a quart of ammonia followed by a quart of bleach. Bend the hose into the hole and cover it with dirt but the exhaust is so much cleaner:) The University uses dry ice at the same time on multiple holes covered with A LOT of wet dirt and then they hold. They standby because the students would remove the dry ice (the non home owners felt it to be cruel) My issue is living between immigrants that believe animals have a place in the world. They do! But not when they damage your property! So she continued to feed them by dumping her table scraps and compost in the alley behind our houses. She felt differently when her yard was excavated for a sewerline break. The workers explained that the absence of support structures caused it to snap. I have used conibear traps in the attic for squirrels, just be careful to do so when there is no chance youll be leaving behind unfed helpless babies. For folks that have groundhogs in open fields contact your local Jack Russell Terrier club. They might have to dig a hole or two to get the dogs out but GO TO GROUND is what JRTs were bred to do. My 16lb baby caught the 30lb animal she was feeding and I left it for her to bury so she could see what she created. Point being if your neighbors arent on board, theyll just comeback later. 16lb JRT foot, 30lb groundhog under the first step closest to the ground. JRT 1: Chuck 0

Since now is another season of SOB, let me chime in... like sewwizard et al, we too got rid of them by digging them up. There were a lot of its clumps spread all over an about 2000 sqft area when we moved in the current house (we didn't know they were there because we purchased the house in summer). Clearly they had been left alone for years and years, resulting in a high population density. We dug them up, and dug DEEP and WIDE, along with all of the soil around them, throwing them into trash bag and disposing. Then before filling back the holes with new soil, we burned those holes with the weed burner torch to make sure any tiny bulblet we might have missed there would be killed. It took over two seasons (yep, it was an intense, laborious process), followed by the following few years when we took care of a few tiny stray plants, but now the area is SOB-free. We had given Dismiss a try once before the elbow grease, but it only burned the top of the plants -- it did not kill them and the plants came back strong (perhaps even stronger) the next season. Perhaps if it had been applied over several years it might have significantly weakened the plants (because it did burn them quite well), we just weren't that patient... ugh, the way they spread randomly was just too ugly for us to be patient! So from my experience, I think the most effective way, if the size of your affected area is manageable, is the most primitive way... dig them up.

This is an unfortunately bad outcome. When you do your best to get rid of a step mother, you might be successful in breaking up their marriage, but if you don't succeed, then you are stuck with a bad relationship with your father AND his wife. That's where you are now. Make the best of it and move on. Maybe things will improve with time, but probably the best you can hope for is to have a relationship with your father only. I think the relationship with his wife is too far gone.