Zinnia
Zinnia elegans
Other names: Common zinnia, youth-and-age
Zinnias are heat-loving annuals with bright, long-stemmed flowers in nearly every color except blue. They bloom within about two months of sowing, attract butterflies all summer, and produce more flowers the more you cut them.
How to grow zinnia
Light
Full sun is essential for strong stems and to keep mildew down.
Watering
Water deeply at the base once or twice a week. Keep the leaves dry, particularly in the evening.
Soil and feeding
Add compost before sowing. A light feed once a month keeps cut-flower plants productive.
Planting and pruning
Sow directly outdoors after the last frost, 1/4 in (6 mm) deep, once the soil is above 70°F (21°C). Zinnias dislike root disturbance. Thin to 9 to 12 in (23–30 cm) apart. Pinch the main stem when plants are 12 in (30 cm) tall to make them branch.
Propagation
Grow from seed. Let a few flowers dry on the plant, then pull the arrowhead-shaped seeds from the base of the petals.
Common problems
- White, powdery coating on leaves
- Powdery mildew, usual by late summer. Space plants well, water at the base and choose resistant series such as Zahara or Profusion.
- Brown spots on leaves and petals
- Bacterial or fungal leaf spot. Remove affected leaves and avoid overhead watering.
- Tall, weak seedlings
- Started indoors with too little light. Direct sowing gives sturdier plants.
Questions about zinnia
When should I cut zinnias for a vase?
Hold the stem about 8 in (20 cm) below the flower and shake it gently. If the stem stays stiff, it is ready. If the head wobbles, wait a few more days.
Do zinnias bloom all summer?
Yes. With regular cutting or deadheading they flower from early summer until the first frost.
Plant details
| Botanical name | Zinnia elegans |
|---|---|
| Family | Asteraceae |
| Native range | Mexico |
| Plant type | Annuals. Annual |
| Soil | Fertile, well-drained soil |
| Flower color | Pink, red, orange, yellow, white, purple |
