Morning Glory

Sowing: Morning glory can be started indoors four to six weeks before the last frost or sown directly outdoors once frost danger has passed and the soil has warmed to at least 60°F. Because its seed coat is hard, nicking it with a file or soaking it overnight in warm water speeds germination, which typically follows within four to seven days at soil temperatures of 65°F to 85°F.

Siting: It grows best in full sun and in moist, well-drained soil that is acid to neutral, tolerating clay, loam, sand, or rocky ground. As a twining vine it needs a trellis, fence, or string put in place before planting, since it climbs by wrapping its stems around thin supports rather than gripping a solid wall unaided.

Care: Once established, plants tolerate dry spells but appreciate irrigation during heat waves, and pruning can be used to keep growth in check. The vine self-seeds readily, so seedlings often reappear the following year and may need thinning to keep it from becoming a nuisance.

Aphids and spider mites are the main pests to watch for, while powdery mildew and root rot are the diseases most likely to affect the plant.

Toxicity: The plant carries a low level of poison risk, with seeds containing indole alkaloids such as lysergic acid and elymoclavine; ingestion can cause vomiting, and large amounts of seed may produce hallucinations, which makes it a recognized problem for cats, dogs, and horses.

Seed capsules form as small, globe-shaped pods roughly a third of an inch wide through summer and fall, each holding several dark, wedge-shaped seeds. Once the capsules dry and split open, the seeds can be collected and saved for sowing the following season.

Morning glory is grown chiefly as an ornamental, valued for funnel-shaped flowers that open in the morning and close by afternoon. It is used to cover trellises, fences, and hanging baskets, or to quickly screen a bare wall or unwanted view, and its blooms attract hummingbirds, butterflies, and pollinating bees, including bees specialized on the genus.

Common morning glory is native to Mexico and Central America and has since naturalized across warm temperate and subtropical regions worldwide, appearing in nearly every U.S. state as well as parts of Canada. It has become invasive in some areas even as gardeners elsewhere have selected numerous cultivars for ornamental use.