jds, I think to fix it you should pull it out, dump out your soil and see if your dahlia tubers have turned to mush. That monster looks awfully familiar as a popular NW weed. I'll take my camera down and get a shot of some leaves, probably little pink flowers too, as I have these same weeds sneaking up in my perennial bed.

Sorry, but that's what I think it is from the photo.

ditto, Steve in Baltimore County.

Aww man. Is the main tall stalk thing salvageable then? I thought the other parts looked too flimsy.

Sorry, I don't see anything that resembles dahlia growth from top right down to soil.

It's been awhile so I guess I forgot what it looks like before it blooms. I hadn't even thought of it being a weed!
Now I feel like a dork for watering it. I had no idea a random weed could grow that tall though!

I'm not a total gardening failure though. I have a giant potted jasmine all twined up a small trellis. And I've had that for I think 3 years now and it's blooming well so far.

No need to feel like a dork. Even the weed appreciates a little TLC once in a while! If you can grow a jasmine there is complete hope! Here is the foliage of what I think is your plant
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A little further away with blossom beginning middle left of center against the horrible backdrop of phlox,spent geranium, crocosmia, a lone foxglove, and sweet woodruff run amok. Not a good photo, sorry. The little pink blooms go on to produce fluffy white tufts of seeds that float away to other portions of the garden if left unpulled, as I recall. The weed is the one with maroonish stem beginning at the bottom of the photo.
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And another closer up of fresher foliage. Nice of me to include it inside the ribbed cage for the asters wasn't it? Even weeds need support:)
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