They like warm weather. Don't start them to early or they tend to sit in the ground and rot.The more the sun the better. They like lean soil. And don't use any fertilizer they tend to grow leaves and no flowers if they are fertilized. Keepthem well watered. And I find here in Maine mine also don't really get going good till late summer.

I agree with fivemeows.
We grow them here in zone 6 every year to cover a trellis. They do not really kick in till it gets nice and hot out. Then they take off big time.
I try to leave mine alone. They like less attention. I fertilized and waterered them generously the first year we grew them and they hardly flowered.

Even down here in North Carolina Zone 8 they don't kick in till mid summer - usually in August but then they grow like gangbusters....

Lynne

I will also add that sowing direct after soaking the seeds overnight works just as well as buying small plants. I agree there is nothing to be gained by rushing them. They like heat.

I started mine in peat pots, soaking the seed overnight and then sowing two to a pot. That was 2 weeks ago - they came up like grass, the flat went outside and they have their second set of leaves and are starting to vine. Now if it will just stop raining so they can go in the ground....
And even with the jump start, they are slow to start blooming.

If I could do it over I would think twice about planting MG. Yes I too was once a lover of these beauties. The first year I had billows of plants growing over an old picket fence. They kicked in around August and didn't stop until frost. Heavenly blue, everyone stopped to admire. The problem is 4 years later I have MG coming up everywhere. I spend more thime removing these beauties from every inch of my gardens, about 1 acre, even out in my lawn. But, in repsonse to your question I agree with other post. Don't feed, don't run water everytime they look droopy and be patient they will come. My advice to you is to make sure you remove all the dead vines after frost to ensure MN and birds don 't scatter everywhere.