Once it warms up and stays warm, the MGs should take off. I planted some Sweet Peas seeds way back in March and they are finally growing. I have volunteer MGs popping up all over and they are averaging about 1ft tall now and growing quickly.

And yes, once they get up to a certain height with no support, they will fall over. They'll often use each other to twine around for support but then when the weight becomes ponderous for them, the whole mass will fall over.

Regarding the sunflowers, the MGs as a vine will out grow the sunflowers for sure and if they make contact with them, will undoubtedly twirl around them for support. I think even if you add stakes, unless you manually guide the MGs, they'll go for the sunflowers too.

I want the mg to go for the sunflowers. The directions I read for making a sunflower house is to tie string across from one sunflower to the next when they reach about 4ft high, so the mg will grow across to create a roof. I'm just concerned that the mg will grow faster than the sunflowers.

Well the MGs may well engulf the sunflowers. I don't think there is much doubt about that! LOL I actually had some form a similar bridge on their own (without a support) between their make-shift trellis and the MGs that were climbing a shepherd's hook.

The below is a shot of the "bridge" of MGs that had formed last summer and it filled in as the summer went along:

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You can see the shepherd's hook engulfed and I bet your sunflowers would have the same fate unless you just snip the tips and let the MGs branch some so the sunflower faces are clear.

I'm across the lake in Madison, WI. My MGs are only a few niches high right now -- but they always "sit" as seedlings and then, around mid-June, seem to start growing about 2 feet a day.

My SPs are only up about 4 inches and I'm not sure here in z5 what they're grow pattern is -- my first year with them.

I agree with the comments above that the MGs will probably completely engulf the sunflowers. I love MGs, but they are monsters. I was shocked the first year I planted them at how vigorous they are!

Have fun and good luck!
Laura

I live close to Toledo, OH and my MGs are starting to take off. I think. One is growing pretty fast and is starting to look like a vine, the other though, is growing upright so far and isn't looking like a vine. I think though, if you guys have been getting the 90's that we've been getting here, yours should start to take off

We've been 80-90's for a few weeks, just now had a cold front come thru and now it's mid 70's (what a cold front huh?) Still nothing. Well they did finally grow their true leaves, and a few seem to be bushing out, but not growing up. I just need to give them time I guess.