I never snip my morning glories, I want them to reach the top of the arbor. Here in zone 5b, the morning glories are just starting to bloom. We've had a cloudy, rainy summer here so far and MG's need full sun to do their thing. The cloudy weather has really effected the blooms. Moonflowers bloom later in the summer. I have both on the same arbor. By August/September the Moonflowers have taken over. The picture is from last September. The arbor was mostly Moonflowers then. They lasted until frost.