USA plant library · annual

Zinnia

Zinnia elegans · Asteraceae

Easy cut flower from seed and a pollinator magnet

Photo: Ermell, CC BY-SA 4.0, via Wikimedia Commons

Sun: Full sun
Soil: Well-drained, fertile soil
Soil pH: 5.5-7.5; tolerates acid to alkaline soil
Water: Moderate. Water at the base
Hardiness: Frost-tender annual, grown in all zones
Height and spread: 0.5-4 ft x 0.67-1 ft

Guv's tipWater zinnias at the base and give them room for air flow. That's your best defense against powdery mildew and leaf spot.

Through the year

When to plant

Sow direct after the last spring frost when the soil is about 70°F (transplants when the soil is about 60°F). The exact month depends on your local frost date

Harvest or flowering

June to frost

Pruning

Deadhead. Pinch young plants

Making more plants

Seed

Watch out for

Pest

Japanese beetle

Look for: Chewed flowers and leaves

What to do: Hand-pick into soapy water early or late in day; netting

Disease

Powdery mildew

Golovinomyces cichoracearum

Look for: White-gray powdery coating on leaves, stems, flowers

What to do: Air circulation, water at soil level, resistant cultivars where available, remove infected plants; labeled fungicide (e.g. sulfur) if severe

Disease

Alternaria leaf spot

Alternaria zinniae

Look for: Reddish-brown to purple spots with gray centers; defoliation

What to do: Space plants for air flow, water at soil level in the morning, remove debris. Grow leaf-spot-resistant cultivars

Always read and follow the label on any treatment, and check it is approved for use where you live.

Safety and spread

Pets and people: Non-toxic to dogs, cats and horses (ASPCA, NC State Extension)

Weed risk: Not on the federal noxious weed list

Checked against two or more reputable gardening sources. How we check our facts

Keep it by the back door

The Plant Doctor and the Guv's book

Printable pest and disease charts with real photographs, and all 50 USA plants in one book.

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