Mexican sunflower

Sun

Full sun; choose a warm position sheltered from strong winds.

Water

Water regularly while establishing, then deeply during prolonged dry spells. Established plants tolerate some drought.

Soil

Well-drained soil of average to modest fertility; avoid waterlogged ground and heavy nitrogen feeding.

Height

4-6 ft (1.2-1.8 m)

Spread

2-3 ft (0.6-0.9 m)

Flowers

Summer to the first frost; orange to orange-red flowers with yellow centres. Yellow-flowered cultivars are also available.

Foliage

Broad, rough-textured, softly hairy green leaves, often with three shallow lobes.

Growth

Fast; reaches flowering size in one growing season.

Care needed

Low

• Pollinators
• Deer resistant
• Drought tolerant
• Heat tolerant
• Wildlife
• Low allergen

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Easy

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   0.6 ft (0.18 m)

2. After 1 year

   5 ft (1.5 m)

   full size

Full size in one season.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Invasive in

Australia

In the garden

Spreads vigorously: plan to contain it.

Growth rate

Fast

• Plant out only after frost danger has passed and the soil has warmed; space plants 2-3 ft (0.6-0.9 m) apart.
• Water at the base until established, then during extended dry weather.
• Avoid rich manure and frequent feeding, which encourage leafy growth at the expense of flowers.
• Apply a light mulch after the soil warms, keeping it away from the stems.
• Stake tall plants early in exposed gardens; their stems can break in strong wind.

Pruning. Pinch out the growing tip of young plants if you want bushier growth. During flowering, snip off faded heads just above a leaf joint, handling the brittle stems gently.

Early spring

In short-summer climates, sow seed indoors about 6-8 weeks before the last expected frost.

Late spring

Harden off seedlings and plant out after frost danger passes, or sow directly into warm soil.

Early summer

Install stakes before plants become tall and mulch once the ground is warm.

Summer

Water during prolonged dry spells and remove faded flowers to prolong the display.

Early autumn

Where the plant is not invasive, allow a few heads to ripen if you want to collect seed.

Late autumn

After frost kills the plants, remove the stems and compost healthy material.

• Place at the back of a sunny border for height and a long season of orange flowers.
• Combine with purple salvias and blue-flowered annuals for strong colour contrast.
• Plant in loose groups with ornamental grasses for a late-summer display.
• Use along a vegetable garden edge to bring flowers and pollinating insects close to crops.

Garden styles it suits: Cottage garden, Hot border, Pollinator garden, Wildlife garden, Mexican hacienda and Tropical.

Plant it with: Mealycup sage, Zinnias, Cosmos, Verbena, Fountain grass and French marigolds.

Wildlife: The open flowers provide nectar and pollen for butterflies and bees. Seed heads may attract seed-eating birds if left to ripen where self-seeding is acceptable.

• Slugs and snails can destroy young seedlings; inspect after dark, remove pests and use wildlife-conscious slug controls where needed.
• Aphids may gather on soft shoots; wash them off with water and encourage ladybirds and other predators.
• Tall stems may snap in wind; plant in shelter and support them with stakes before they reach full height.
• Poor flowering often follows cool weather, shade or excessive nitrogen; choose the warmest sunny site and reduce feeding.

Not known to be toxic to people, cats, dogs or horses, but species-specific safety information is limited. It is not an edible plant; discourage eating any part. Rough foliage may irritate sensitive skin.

Where it spreads. Invasive in parts of South Africa and recorded as an environmental weed in Queensland, Australia. It can self-seed readily in warm climates; check local guidance before planting and prevent seed production where escape is a concern.

• Tree marigold (Tithonia diversifolia)

  Usually a larger, woody perennial shrub with more deeply divided leaves and predominantly yellow flowers; Mexican sunflower is an herbaceous annual with shallower leaf lobes and usually orange-red flowers.

• Common sunflower (Helianthus annuus)

  Usually has more distinctly heart-shaped, toothed leaves and larger flower heads with prominent seed-forming centres; Mexican sunflower has smaller heads on long stalks and often lobed leaves.

The common name refers to its Mexican origin and sunflower-like flower heads.

Propagation. Grow from seed, sown indoors before the last frost or directly outdoors once the soil is warm. Cover lightly and keep evenly moist until germination. Saved seed from named cultivars may not produce identical plants.

Accepted botanical name

Tithonia rotundifolia

In the US and Canada

Introduced in the lower 48 states, Puerto Rico and US Virgin Islands.

Native range

Belize, Costa Rica, El Salvador, Guatemala, Honduras, Mexico Central, Mexico Gulf, Mexico Northeast, Mexico Southeast, Mexico Southwest, Nicaragua and Panamá.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.