I never thought of that Don, but you are right to wonder. Amazing how plants develope to survive and produce as they should.

I have a Silver Lace Vine climbing an old Maple Tree right now. It doesn't have the tendrils, but it seems to know where to go. At least I think it does. It grew over 30 feet last year without any help from me, and this year it's going for the sky!

And here I can't get a doggone morning glory to grab onto the teepee I planted it under...

And my morning glories are growing away from their support as if they were repelled by it! Why don't they know?

I planted a couple underneath some shepherd's hooks that are holding up a couple hanging baskets. I was amazed by how easily they grabbed on and twirled themselves around. It's like they have a mind of their own. I have my very first morning glory flower this morning! It's Clark's Heavenly Blue ... very pretty color and larger than I thought it would be. For some reason, one of the vines is twice as long as the other though. The long one looks healthier, but the short one is the one with the flower.

I also have some cameo elegance morning glory I planted in a pot. I put a trellis toward the back. The foliage is beautiful and variegated, but plants are still quite short, and the few short tendrils there are have not grabbed a hold of the trellis yet even though I've tried to guide them there. So maybe it depends on the type of morning glory.