How to Plant, Grow, and Care for Ipomoea Tricolor

Ipomoea tricolor, the Mexican morning glory or grannyvine, is a lovely trellising plant with trumpet-shaped blue, pink, or white flowers. Lorin Nielsen will show you our growing guide that teaches you all you need to know!

Lovely and dainty Ipomoea tricolor flowers appearing to have a deep shade of blue, blooming along a trellis supporting the plant's weight

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Ah, grannyvine! Or Mexican morning glory, or just morning glory. No matter what you like to call it, Ipomoea tricolor is a garden stunner. This annual climbing vine produces trumpet-like heavenly blue, pink, or white flowers.

If you’re looking for a fast-growing plant to trellis, this is a great choice. It will rapidly clamber upwards and fill in all available space. Trained up over an arch, or encouraged to cover a pergola, it makes for a beautiful display of flowers.

We’re going to talk all about these phenomenal flowering vines today. It’s not hard to grow them, and you’ll find they’re very willing to work with whatever space you have to spare!

Plant Overview

A plant with Mexican morning glory flowers looking vibrant and beautiful still attached to stems and leaves that are bright green
Plant Type Herbaceous annual or perennial
Family Convolvulaceae
Genus Ipomoea
Species Ipomoea tricolor
Native Area Mexico
Exposure Full Sun
Height 15’
Watering Requirements Moderate
Pests & Diseases Aphids, mites, leaf miners. Also leaf spots, rots, rust, and blister
Maintenance Low
Soil Type Well-draining, sandy or loamy
Hardiness Zone 2-12

What is Ipomoea Tricolor?

In USDA zones 3-10, Ipomoea tricolor is a common sight. This is especially true in warmer climates where it can create a screen of vines and flowers, some of which are heavenly blue!

Used regularly to fill in landscaping, this vine is a speedy grower. It rarely becomes invasive, although it can self-seed if the seed heads aren’t removed.

Native Area

Lovely-looking purple Mexican morning glory blooms appearing soft and delicate among deep green foliage surrounded by other greens
They are native to Mexico and warp tropical regions.

Indigenous to the warmer tropical regions of the Americas like Mexico, it’s grown worldwide now. This species is well-adapted to a variety of environments within its native range, including forest edges, disturbed areas, and open spaces with ample sunlight. Its hardiness and ornamental beauty have led to its cultivation worldwide, though in some regions, it is considered invasive.

Characteristics

Close-up of a Morning Glory vine with deep purple bell-shaped flowers, green heart-shaped leaves, and twisting vines.
They have tendrils and vines that tend to climb.

Growing from six to fifteen feet in height, Ipomoea tricolor is as likely to creep up a tree or the side of your house as a trellis. Small tendrils extend off the vine and grab onto most surfaces, even other vines!

The leaves are heart-shaped and quite appealing on their own. But most people grow these vines for their trumpet-like flowers. It’s called “morning glory” because its flowers open to the first touches of the morning sun. In fact, they won’t bloom in mid-summer without sunlight!

The Mexican morning glory flower tends to be vividly heavenly blue, purple, pink, or perhaps ranging to purplish. “Tricolor” refers to the pale yellow center and the streaks of white that form a star shape along the petals.

Other Ipomoea species (including Ipomoea purpurea and Ipomoea nil) are also commonly called morning glories. Although they’re related, these aren’t the same species as Ipomoea tricolor. Today, we’re going to stick with the tricolored variety and its growing conditions, but many other species are out there.

The term “grannyvine” is a common name used for wild-growing Ipomoea tricolor. It’s a more accurate term than “morning glory”, simply because it’s less likely to be confused with other species! However, it’s less fashionable. Whether you call your plants grannyvines or heavenly blue Mexican morning glories, you’ll have something stunning to see.

The ‘Heavenly Blue’ morning glory cultivar won the Royal Horticultural Society’s Award of Garden Merit. This variety is what most people think of when they’re referring to this species, and its stunning display is what earned it the Garden Merit award. If you can’t find one of these, look for the blue star cultivar, as ‘Heavenly Blue’ is a darker blue star.

Planting

Close-up of a bell-shaped flower with delicate purple petals and a white throat, supported by heart-shaped green leaves and twining stems that climb and spread.
Place them somewhere with enough sunlight.

To plant Ipomoea tricolor, choose a sunny location with well-draining soil enriched with compost. Nick or lightly sand the hard seed coat and soak the seeds in warm water for 24 hours to enhance germination. Sow the seeds directly into the soil in spring after the last frost, planting them about 0.5 inches deep and spacing them six to twelve inches apart. Water thoroughly after planting and keep the soil moist until the seeds germinate, which usually takes 7–14 days.

Provide a sturdy support structure like a trellis or fence for the vines to climb. Once established, Morning Glory requires minimal care. It thrives with occasional watering and light pruning to encourage blooming and control growth.

How to Grow

If you provide a fence or trellis for this plant to climb, good sunlight, and water, your grannyvine will do the rest. With insane speed, it can rapidly grow to heights of almost 15 feet tall. The vines will spread out sideways once they run out of climbing surface.

It’s not a very picky plant, but we’ve got tips to help you provide the best conditions for growth.

Light

A close-up of blue morning glory flowers, unfurling their delicate petals. A cluster of leaves gracefully intertwines with the blooming morning glory flowers, providing a verdant contrast to the azure blooms.
Full sun is ideal for these flowers.

Sun-worshipping Mexican morning glory blooms its best with lots of light. While they can tolerate partial shade, they’re truly best in full sun conditions. Heat is less of a worry as long as the plant has enough water. The heart-shaped leaves provide some built-in shade to protect the vine.

Those stunning, trumpet-shaped flowers that are sometimes ‘Heavenly Blue’ do require full sun to open in the morning. Ensure they’ve got morning sunlight for the best display!

Water

Close-up of hands wearing white gloves, grasping a pile of light brown mulch with small, uneven wood chips, surrounded by more mulch spread on the ground.
Mulch around these plants to keep them moist.

You’ll need about an inch of water per week to keep your plants happy. In hot weather, provide a bit extra moisture when it’s necessary. Mulching at the base of the plant helps reduce moisture evaporation.

When starting from seed, newly-germinated plants or very young seedlings like humid air. As they develop and put down roots, they harden off to average or dry conditions. Once established, older plants can be surprisingly drought-tolerant. In areas where there are regular dry winds, pick a location that’s sheltered to prevent rapid drying.

Plants grown in containers will need more water than ones in the ground. Containers often allow for faster evaporation. Maintain damp but not soggy soil conditions.

Soil

Hands wearing bright blue gloves holding a generous scoop of fresh, dark potting soil, with green foliage and natural outdoor light in the background.
Choose well-draining mix options, especially for young plants.

Well-drained soil is key for these plants. While the soil must remain moist as young plants grow, any pooled water will cause problems. It’s better to opt for drainage over moisture retention for ipomoeas.

Moderately fertile soil will produce better growth and blue flowers. Older plants can tolerate poor soil conditions, but they may flower less. Avoid soils with lots of composted material, as they’re too rich for your plant. Ideal soil conditions would be sandy to loamy. Try to avoid clay-like soils. While they can grow in hard clay, it slows root development.

The soil pH is best between 6.0-6.8, but can tolerate up to a 7.5 soil pH. A few cultivars are sensitive to higher alkalinity. This sensitivity manifests as a slightly modified flower color, although it’s not significantly changed.

Temperature

Vines showcase a cascade of soft blue, funnel-like flowers, accompanied by glossy, heart-shaped leaves and slender stems that twist and climb as they grow.
These blooms prefer warm climates.

Ipomoea tricolor is best when treated as a warm-weather annual. Conditions below 45°F (7°C) damage the heart-shaped leaves and stems. Plant them out once the weather is consistently above 50-55°F (10-13°C), and they’ll thrive.

In deserts or other areas that regularly spike above 95°F (35°C), afternoon shade can be good.

This plant can be grown as a houseplant at a consistent 70°F (21°C). However, it’s tricky to provide enough light indoors, and it may not thrive unless it has lots of direct sunlight.

Fertilizer

A yellow-gloved hand adeptly manages a blue pail filled with white fertilizer granules. In a harmonious motion, the other hand carefully adds granules to the pail, with the scene set against a soft backdrop of blurred, verdant green grass.
Fertilize using options that have high nitrogen content.

If planted in moderately fertile soil, no fertilizer is necessary. For plants in poor soil, opt for a low-nitrogen fertilizer every four to six weeks. Stick with a diluted formula when possible. Balanced or high-nitrogen fertilizers will promote vine growth over flowering.

Need more clarification about how much to use? Opt for under-fertilization for these. They truly only need a little to do well. If you have the right conditions, pink, white, purple, or blue flowers will bloom.

Maintenance

Blue morning glory flowers surrounded by lush leaves, spilling over a garden wall.
Prune based on the cultivar with some growing very small and others reaching up to 15 feet.

Training your vines is more important than pruning. As some cultivars can reach heights of up to 15 feet, you can prune to maintain height. But it’s generally better to provide a space where they can grow to their own preferences!

These ipomoeas love to climb, and will attach onto wooden trellises with ease. Even a sturdy stake will provide a good surface for the vine’s tendrils to grasp. If you’ve only got metal trellises, those will work. You may need to add a little extra support by using plastic plant tape to tie the main stems in place.

Keep an eye on your plant, and direct vines back towards the trellis rather than allowing them to splay out. This prevents the plant from creeping towards other surfaces to cling to. As a shade plant over arches or patios, you can encourage the vines to grow in a particular direction. Simply weave the vines through the growing surface, or use plant tape to secure them in place.

If it’s absolutely necessary, you can prune errant stems. Prune off dead or diseased foliage as needed. To prevent self-seeding, snip off faded flowers as quickly as you can.

Propagation

With its striking, funnel-shaped blooms in bright pink, the plant displays large, broad, green leaves and thin, twisting stems that climb and spread across the fence.
Once established, this plant will reseed when left alone.

Your Mexican morning glory will happily reseed itself if left to its own devices. Growing them from seed is the easiest method of propagation.

Once the flowers fade, they will form seeds with surprising speed. If you wish to collect the seed, place a paper bag over the seed head and secure it with string or a rubber band. If you want it to self-sow, leave the faded flower in place.

To propagate, plant seeds a quarter of an inch deep in moist soil. Maintain a soil temperature at or above 65°F (18°C) until germination has occurred. Provide humidity for newly-germinated seeds. Start hardening them off to drier air once the plant has reached four inches in height.

The seeds are quite hard, and may germinate faster if they have been scratched. To scarify your seeds, rub them briefly between sandpaper to scratch the seedcoat. Place scarified seeds into water for up to 24 hours before planting.

While you can propagate from cuttings, it’s a much slower process and the plant may be weak. It’s far easier to plant new seeds than to try to root cuttings.

Common Problems

Most problems with ipomoea tricolor are disease-related. The diseases which impact this plant often are hard to combat. Thankfully, they aren’t very common. Let’s go over what might arise so you know how to handle it!

Growing Problems

Deep, rosy brown flower with velvety petals with white edging and a subtle, complemented by heart-shaped, lush green leaves.
They might not perform well because of light or watering issues.

Yellowing leaves can be caused by many problems. The most common causes, though, are light or watering-related.

Too much watering or not enough watering both cause yellowed leaves. Too little sunlight will also cause yellowing. It may take a bit of trial and error to figure out what the cause of yellowing leaves is. These are what you should check first. Remedying these issues will often restore the vigor of your plant.

Pests

Close-up Spider mites, tiny arachnids with translucent bodies and eight legs, weaving fine webs around plant stems.
Various insects attack this plant, including spider mites.

Most pests don’t do lasting damage to this plant. But there’s still those which feed upon it!

Aphids, particularly the cotton aphid, will suck plant sap from the heavenly blue leaves. These are easily treated with a misting of neem oil. As an alternative, you can blast them off the leaves with a hard spray of water.

Spider mites are another common sucking pest. These tiny mites can be eliminated with neem oil as well.

Leaf miners are a bit trickier. The larvae will actually move into the leaf, making it hard to eradicate them. Prune off and destroy leaves with visible leaf miner damage. Use neem oil or a bacillus thuringiensis (BT) spray to prevent further spread.

Caterpillars of all sorts find morning glory leaves to be tasty treats. bacillus thuringiensis in either spray or powdered form will eliminate them.

Finally, this is one of many plants that deer will consume. Of all the pests mentioned here, they’re most likely to cause lasting harm. They will eat both the leaves and the vines, and having a herd of deer come through may destroy your plant. If you live in an area where deer are common, consider using deer repellents, and don’t plant your blue star where they can access it.

Diseases

Close-up of a tomato bush affected by Fusarium Wilt, displaying browning and wilting of leaves.
Different fungal infections appear on this plant, such as fusarium fungi and downy mildew.

White blister is a disease that’s quite similar to downy mildew. It is caused by an oomycete spore, which causes white leaf spots. These spots gradually turn into blister-like pustules of powdery white spores.

Removing leaves and stems which show signs of blister formation is essential. The faster they are removed, the less likely the spores will spread. Destroy any infected material.

Fungal leaf spots such as alternaria are also common in ipomoea species.

Stem rots, like those caused by fusarium fungi, may occur in some plants. There’s no cure for fusarium-based rots currently. Because of this, prevention is extremely important. Ensure there’s good airflow around your plants, and make sure that the soil does not get too soggy. This slows the development of fusarium.

While it’s uncommon, thread blight from orchard trees can spread to your morning glory. This causes wilted, brown leaves on the inner shaded portions of the plant. Sometimes, a white, thread-like mycelium can be found on leaf surfaces.

Using sterile pruners, trim out infected materials. Sterilize your pruning shears between cuts by dipping them into a solution of one part bleach to nine parts water. Ensure there’s good airflow around your plant.

Finally, an assortment of rust diseases may strike your Mexican morning glory. Avoid overhead watering to prevent their spread.

Frequently Asked Questions

Is Ipomoea tricolor poisonous?

Morning glory seeds are considered toxic. They contain lysergic acids which can cause hallucinations (much like the drug LSD). They also can cause a range of symptoms from nausea or vomiting to diarrhea. The leaves and stems typically only cause vomiting.

This toxicity is not just for humans – it’s true for our pets, too. Keep small children and pets away if they’re prone to snacking on your plants.

Is Ipomoea and morning glory same?

It is, yes. Ipomoea is the genus that houses all morning glories.

Is Ipomoea tricolor invasive?

Yes, in New Mexico, Ipomoea tricolor is invasive. Elsewhere it generally doesn’t escape cultivation.

Is Ipomoea tricolor poisonous to touch?

No. Touching the plant will not cause any problems. Eating the plant, on the other hand, is not recommended.

Does Ipomoea tricolor come back every year?

Yes! While it’s not a perennial, it will annually reseed.

Do Ipomoea tricolor prefer sun or shade?

They need full sun to thrive, so pop them in a sunny area along a fence or trellis.

Do hummingbirds like Ipomoea tricolor?

Yes! Hummingbirds love these (sometimes) heavenly blue and blue star flowers.

Is Ipomoea tricolor illegal?

While there are aquatic Ipomoea species that are illegal, the terrestrial forms are not.

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Close-up of a Morning Glory vine with deep purple bell-shaped flowers, green heart-shaped leaves, and twisting vines.

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