Mexican zinnia

Mexican zinnia: how do you recognise it?

Habit

Bushy, branching annual 30–40 cm tall and about 30 cm wide.

Leaves

Narrow, lance-shaped to linear, opposite, 3–6 cm long; rough to the touch.

Flower

Daisy-like flowers of 3–5 cm, single or double, from July to October.

Colour

Orange, yellow, white or mahogany; often two-toned.

Roots

Shallow and fine; it dislikes being moved, so sow in separate pots.

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

Why grow it?

• Flowers from July to October, without a break until the first frost.
• Smaller and tougher than the common zinnia, with fewer problems from mildew and drought.
• Attracts bees and butterflies.
• Compact and bushy: perfect for containers, pots and the front of the border.
• Easy from seed and cheap, with a warm range of colours.

Mexican zinnia: where does it grow best?

• Full sun: the warmer, the richer the flowering.
• Well-drained, moderately rich sandy, loamy or clay soil, acid to chalky.
• Dry to normal: it tolerates drought, but not permanently wet soil.
• Allow 20–25 cm between plants and choose a spot with good air circulation.

Light

Sun

Soil type

Sand, loam or clay

Acidity

Not fussy

Moisture

Dry or normal

Size

0.35 m tall, 0.3 m wide

Hardiness

Frost tender: plant out after the last frost (mid-May)

Goes well with

• Cosmos: Airy flowers and fine foliage beside the sturdy zinnias.
• Pot marigold: Orange flowers in the same sun, with a soft contrast colour.
• Salvia: Blue or purple spikes contrast with the orange zinnias.
• Verbena: Purple flowers and an airy structure above the low zinnias.
• Lavender: Scented leaves and blue spikes in the same dry sun.

Mexican zinnia: when and how to plant it?

Plant in May–June.

1. Sow indoors in April, one seed per 7–9 cm pot, 0.5–1 cm deep, at 20–24 °C; it germinates in 4–7 days.
2. Keep the seedlings bright and cool at 15–18 °C so they stay compact.
3. If you prefer to sow in place, do so in late May in a sunny spot.
4. Plant out from late May to June, 20–25 cm apart, without disturbing the roots.
5. Water in at once; keep the foliage as dry as possible.
6. Pinch out the tip above the third pair of leaves if you want a bushier plant.

Care

Water

Moderate: water at the base in long dry spells, in the morning so the leaves dry quickly.

Feeding

Occasionally: a flower feed every 2–3 weeks in pots; in the border, compost at planting is enough.

Deadheading

Cut off faded flowers for longer flowering and new buds.

Air circulation

Do not crowd the plants: this keeps the foliage dry and mildew away.

Collecting seed

Let the last flowers ripen on the plant and dry them; seed from two-toned or double forms does not always come true.

Tip: Sow indoors in April or in place in late May and give it a sunny, airy spot. It flowers until frost; cut off faded flowers for new buds.

Mexican zinnia: when to prune it?

When: It is not pruned; pinch out young plants if you like and cut off faded flowers during summer.

How:

• Pinch out the tip of young plants above the third pair of leaves if you like.
• Cut off faded flowers, just above a pair of leaves, for longer flowering.
• Remove affected or withered leaves.
• After the first frost, pull up the whole plant.

Pruning calendar and basic rules

Propagation

Sowing indoors

In April, one seed per 7–9 cm pot, 0.5–1 cm deep at 20–24 °C. It germinates in 4–7 days.

Sowing in place

In late May in a sunny spot, 0.5–1 cm deep; thin to 20–25 cm. Flowering starts a little later.

Mexican zinnia: how does it get through the winter?

Hardy to 2 °C: protect in harsh winters.

• An annual and frost-tender: below about 2 °C it suffers, and at the first frost it dies.
• It does not overwinter outdoors; keep seed dry and sow again in spring.
• In a pot you can leave it a little longer in a bright, frost-free place, but flowering is then over.

Diseases and pests

• Powdery mildew: White powder on the leaves, especially in close, humid late summers; it is less susceptible than the common zinnia. Leave space, water at the base and cut off affected leaves.
• Slugs: Young plants are nibbled. Use iron phosphate pellets or collect them in the evening.
• Leaf spot: Brown, ringed spots on the leaves (Alternaria) in wet conditions. Water at the base, leave space and cut off affected leaves.
• Damping off: Seedlings rot at the base: too wet and too close. Sow in clean compost, water less and ventilate more.
• Aphids: On young shoots. Rinse with water or let ladybirds do their work.

Through the year

• April: Sow indoors in separate pots.
• May: Harden off. Plant out or sow in place in late May.
• June: Finish planting. Water in dry weather.
• July: First flowers. Cut off faded flowers.
• August: Full flower. Bees and butterflies arrive.
• September: Keeps flowering. Let seed ripen.
• October: Last flowers. Clear up after the first frost.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Butterflies

Nectar for butterflies.

Did you know?

• The genus Zinnia is named after Johann Gottfried Zinn, a German botanist and physician of the 18th century.
• This species is also called Zinnia angustifolia, which means ‘narrow-leaved’.
• Crosses with the common zinnia gave the well-known compact hybrids (Zinnia marylandica), which suffer less from mildew.