Now that you know it, look out for others - if you had one there will be more. Awful plant.

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

I love the sumacs on my country property - note the word country. I have no problems with them growing in the roadside ditch or on the edges of the forested areas - they don't grow at all under a canopy. When they sprout up in the grassy areas abutting the woods they simply get mowed down with everything else, or pulled up if they start to encroach into the gardens. I wonder if people growing them in the city have tried just mowing - if a tree can't get nutrients via sunlight even the roots will die off eventually, I would think.

I think you've got a sumac. Not sure which one yet. So I forget-is there pubescence on the leaf petioles? As to the presence or lack thereof of fruit, that's wholely to do with plant maturity. And certainly, the brilliant red (I think you said) fall foliage color is certainly a sumac thing. As to ultimate plant size, most species make rapid growth in youth and then slow down. As such, a young plant already having acquired what is said to be half the ultimate height is no big deal. It can happen and does all the time. Plus, all height estimates are just that-estimates. The trees and shrubs are not reading our books! +oM