Grannycore

I'll be happy to trade you comfrey. I grow the traditional (medicinal) true comfrey - not blocking or Russian. It's true that it spreads, but I've not found it to be wildly aggressive - I've had much more problems with St. John's wort. It definitely increases area each year, but doesn't show up all over the yard. It is persistent, however. I pulled all mine out and moved it last fall, and expect it to take years, if at all, to completely eradicate it from its previous area. Each root that breaks becomes a new plant. Overall I like it and have been glad to have
it - it's beautiful, covers itself in purple flowers, and makes copious amounts of mulch-able leaves. Just know that at least in my zone ...once you have it, you will always have it, and so wil the people you sell your house to.