If morning glories do not bloom, the problem is often an overly rich soil, according to Bachman's. They thrive in rather poor soil conditions without too much water and plenty of sun. Wet, overcast summers and overfertilizing causes the plant to put all of its energy into growing vines without producing flowers.
As indicated by their name, morning glories bloom in the morning, and the blooms on most varieties close by noon. If the other conditions are right for blossom formation but a gardener does not see any blooms, the problem is sometimes one of scheduling. By the time he returns from other obligations, the blooms have closed for the day. Since each flower lasts just one day, he may see spent flowers and think the plant is casting them off before they get a chance to open.
With proper timing and conditions, these plants generally form an abundance of blooms. The flowers are deep-throated and attractive to hummingbirds and butterflies. The heart-shaped leaves form a dense shade. The vines require support and easily wrap around string or other thin material. There are few diseases of insects that affect morning glories. Rarely, aphids, spider mites, inchworms or flea beetles cause problems.