Mexican sunflower

Tithonia rotundifolia

In other languages: Mexicaanse zonnebloem (Nederlands) · Tournesol mexicain (Français)

Mexican sunflower is a robust annual from Mexico and Central America, in the same family as the sunflower and the dahlia. In a single summer it grows into a broad plant of 1–1.5 m with large, velvety leaves. From July until the first frost it carries single flowers of about 7 cm in fiery orange with a yellow centre; there are also yellow forms. Gardeners grow it for its warm colour in late summer, as a cut flower and because butterflies, bees and bumblebees flock to it. Well-known varieties are the tall ‘Torch’ and the more compact ‘Goldfinger’.

Updated on 9 October 2026

Light
Full sun
warm and bright
Moisture
Dry to normal
no wet feet
Legal basis
Sand, loam or clay
any pH
Hardiness
down to 2 °C
protect in harsh winters
Size
1.5 m
tall, 0.6 m wide
Flowering
July–October

Key facts
Height	1.5 m
Native to Belgium	No, planted
Good for bees, butterflies and birds	Yes, for bees and butterflies
Poisonous to people and pets	Not known to be poisonous
Flowering	July–October

Identify

Mexican sunflower: how do you recognise it?

Habit: Upright, branching annual, 1–1.5 m tall and about 60 cm across, with sturdy, hairy stems.
Leaves: Large, oval to triangular, sometimes lobed, dark green and velvety.
Flower: Single flower heads of about 7 cm with orange ray petals around a yellow centre, from July to October.
Colour: Orange to orange-red; yellow in some varieties.
Stem: The flower stalk is hollow and swells just below the flower; it snaps easily.

Flowering: July–October · Sowing: March–April · Plants: May–June

In your garden

Why grow it?

Fiery orange flowers from July until the first frost: an eye-catcher in the late-summer border.
One of the best annuals for butterflies; bees and bumblebees visit the flowers too.
Quickly reaches 1.5 m: ideal for filling a gap or the back of a border in one season.
A lovely cut flower with long stems for a summery bouquet.
Copes with heat and drought and does not need rich soil.

Mexican sunflower: where does it grow best?

Full sun and warmth: the hotter the summer, the better it grows and flowers.
Ordinary to poor, well-drained soil: sand, loam or clay, acid to chalky. In very rich soil it becomes floppy.
Dry to moderately moist: once rooted it tolerates drought well.
Sheltered from strong wind, as the tall stems can blow over. Plant 50–60 cm apart.

Light: Sun
Soil type: Sand, loam or clay
Acidity: Not fussy
Moisture: Dry or normal
Size: 1.5 m tall, 0.6 m wide
Hardiness: Frost tender: plant out after the last frost (mid-May)

Goes well with

Dahlia: The same warm colours and the same late flowering.
Zinnia: A colourful, shorter annual at the front, just as fond of heat.
Purpletop vervain: Purple clusters among the orange, another butterfly magnet.
Ornamental grasses: Swaying stems as a contrast to the coarse leaves.

Maintenance

Mexican sunflower: when and how to plant it?

Plant in May–June.

Sow indoors in March–April, ideally in April, two seeds per 8–9 cm pot, 0.5–1 cm deep, at 18–20 °C; keep the strongest seedling.
Grow the seedlings in good light and not too warm, so they stay sturdy, and pot them on into a larger pot if needed.
Harden them off outdoors for a week in May and plant out after mid-May in a warm, sunny spot.
Set them at the same depth as in the pot, 50–60 cm apart, and put in a sturdy stake straight away for tall varieties.
Water in well and keep the soil just moist for the first few weeks.

Care

Watering: Water regularly after planting; after that only in long dry spells. More often in a pot.
Feeding: Best avoided: too much feed gives lots of leaves, floppy stems and fewer flowers. A little compost at planting is enough.
Support: Tie tall plants to a sturdy stake or run string around a group, especially on a windy site.
Deadheading: Cut off faded flowers regularly back to the next side shoot: the plant then keeps flowering for longer.
Cut flowers: Cut them in the morning, just as they open, and handle the hollow stems gently.

Tip: Go easy on the feed: on poor, warm soil Mexican sunflower stays sturdier and flowers more freely than on rich soil.

Mexican sunflower: when to prune it?

When: An annual that needs no pruning. You can pinch young plants and deadhead all summer.

How:

Pinch out the tip of young plants at about 30 cm for a broader, sturdier plant with more flowers.
Cut off faded flowers just above a leaf or side shoot.
Pull the plant up after the first frost and put it on the compost heap.

Pruning calendar and basic rules

Propagation

Seed: Sow indoors in March–April at 18–20 °C. In a warm late summer you can save your own seed from heads that have ripened and dried on the plant; store it dry and cool.

Mexican sunflower: how does it get through the winter?

Hardy to 2 °C: protect in harsh winters.

Not hardy: it does not tolerate temperatures below about 2 °C and dies at the first frost.
Clear the plants after the first frost and sow again in spring.
If you want to save seed, leave a few good flowers to ripen in September.

Diseases and pests

Blackfly: Black aphids on the stem tips and under the flower buds. Spray off with water or cut off the worst tips; ladybirds help.
Slugs: They strip young plants in May–June. Protect them for the first weeks and pick slugs off in the evening.
Flopping or snapping: Tall stems blow over or break in wind and rain. Stakes, a sheltered spot and pinching help.
Late flowering: After a cold, wet summer it flowers late. Plant out into warm soil and choose the sunniest spot.

Through the year

March: Sow indoors at 18–20 °C.
April: Sow indoors. Pot on seedlings.
May: Harden off. Plant out after mid-May.
June: Plant out. Put in stakes. Pinch young plants.
July: Flowering starts. Butterflies on the flowers.
August: Full flower. Cut flowers. Deadhead.
September: Flowering. Water in long dry spells. Let some seed ripen.
October: Last flowers. Clear away after the first frost.

Use

Good for wildlife

Bees: Nectar and pollen for honeybees and wild bees.
Butterflies: Nectar for butterflies.

You and this species

Did you know?

Tithonia is named after Tithonus from Greek mythology, the lover of Eos, goddess of the dawn.
The flower stalk is hollow and swells just below the flower: that is why it snaps so easily.
Despite the name it is not a true sunflower, but it is related: both belong to the daisy family.

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