Tall morningglory

About

A vigorous twining vine from Mexico and Central America, sometimes grown for its purple, pink, blue or white trumpet flowers. It reseeds heavily and climbs over crops, fences and shrubs, and its hard seeds last for years in the soil.

Also called common morning glory, purple morning glory, tall morning-glory

How to identify it

Look for

Seedlings have butterfly-shaped seed leaves. Leaves are heart-shaped, 1-3 inches, with fine hairs that lie flat against the surface, on hairy, often purplish stems. Flowers are about 1.75-2.75 inches long, in clusters of three or more, and open in the morning and close by afternoon.

Look-alikes

Ivyleaf morningglory has three-lobed leaves with hairs that stand straight up, and pitted morningglory is hairless.

Where it grows

Vegetable gardens, crop fields, fences and garden edges, and it is worst in warm, humid areas.

When

Sprouts from late spring into summer with a peak in early summer, begins blooming 6-8 weeks after emergence, and keeps flowering and setting seed until frost.

How it spreads

By seed; a plant can make about 26,000 seeds with no competition, and the hard seed coats let seeds persist in the soil for years.

Most common in

Where it is regulated

Morningglory seeds (Ipomoea species) are noxious weed seeds under state seed laws in states including Arizona (prohibited) and Arkansas, Hawaii and Kansas (restricted).

What to do, gentlest first

Protect yourself first. Weed killers are a last step; always read and follow the label.

1. Deadhead garden plantings and clean up edges Prevent

   If you grow it on purpose, remove spent flowers before the capsules ripen, and pull volunteer vines along fences and edges before they seed. A stale seedbed (water, let seeds sprout, then shallowly cultivate) knocks out a flush before planting.

2. Pull seedlings before 5 inches By hand

   Hand-pull or hoe seedlings before they are about 5 inches long and start twining around your plants.

3. Use plastic mulch or solarize Barrier

   Plastic mulch blocks seedlings, but straw does not. Solarizing moist soil under clear plastic in hot weather kills many seeds near the surface.

Uses, wildlife and pets

For wildlife

Bumblebees, specialist morning-glory bees, butterflies and hummingbirds visit the flowers.

Pets

Morning glories (Ipomoea species) are listed by the ASPCA as toxic to dogs, cats and horses; eating the seeds can cause vomiting, and large amounts may cause hallucinations.