Sure it isn't tansy, and not yarrow? Aromatic, fern-like, flat leaves with small yellow button flowers. It spreads by seeds and underground runners.

Here is a link that might be useful: tansy

YES! It is tansy. Thank you! I never saw this before, it was labeled as yarrow, and, like a fool, I planted it.

I REGRET IT! The underground runners are killer.

Definitely stay away from any variety that has "Achillea millefolium" in the name. They can be uncontrollable.

I've had the same clump of Achillea "Anthea" for years and it never gets out of hand. It's a nice light yellow that is not garrish and goes with everything. No underground runners!

I also have some King Edward Dwarf Yarrow or Wooly Yarrow and it has not caused any problems either. It's just so cute and small. Great for the front of the border.

Linda

Don't feel bad, Jayco. I bought the same thing from Kmart several years ago, labeled 'yarrow' and had the same terrible results. The foliage also stunk !!

Ended up having to tear up that part of garden and start all over. Therefore, I hated yarrow. However, I did take a chance and buy 'Red Velvet' this year and it already has that pretty fern-like foliage like you said. So am now really looking forward to seeing it bloom !! I feel better too, knowing what I had before was not "true" yarrow.

Here's how big it is already !!

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Pretty! I actually love the ferny foliage of true yarrow. Mine is also kind of aggressive but it's so easy-care and I love the flowers. I can always chop it back in the spring and keep it in bounds.

So, now an update on my tansy situation:

First, a thousand thanks to Mosswitch for telling me what it was, since I immediately Googled it and found out that there were probably still roots everywhere and I should go back out and dig it up again, so I did. Talk about a PITA! That thing had sent its roots out everywhere, over and under other plants' roots, and it was very difficult to get it all out. I *think* I did, and now I will always recognize and shun the evil tansy.

Still like yarrow though!