Zinnias: How to Plant, Grow, and Care for Bold Annual Color

Picture of a zinnia from my garden

Tammy Wilson

Zinnia flowers are among the easiest plants to grow, growing quickly and blooming heavily. They create a massive color burst and attract butterflies.

Zinnias are annuals—one season of growth, superb cutting flowers. Bright, solitary, daisy-like flowerheads on single erect stems. Most common: "dahlia-flowered" to 3 feet. Others: "cactus-flowered."

Use in annual/mixed borders. Smaller zinnias suit edging, window boxes, containers. Narrow-leaf zinnias work in hanging baskets.

Planting Zinnias

• Grown from seed; grow quickly in right conditions. Zinnias dislike transplanting.
• Full sun essential; minimum daytime temp 60°F.
• Adaptable but prefer fertile, humus-rich, well-drained soil, pH 5.5–7.5.
• Compost-amended soil speeds growth.
• Sow seeds ¼-inch deep.
• Space 4–24 inches apart by variety (common: 6 inches in row, 2 feet between rows). Check seed packet.
• Germination at 74–80°F in 5–7 days (not 76 days as previously misprinted).
• Succession sow for longer flowering display.

Care

• Deadhead to prolong flowering.
• Maintain moderate soil moisture; fertilize lightly.
• Zinnias die with first frost.

Pests and Diseases

Bacterial/fungal spots, powdery mildew, bacterial wilt. Minimize foliage wetting to avoid disease.

Caterpillars, mealybugs, spider mites also cause problems. Avoid spraying; tolerate some leaf damage unless uncontrolled.

Luckily, zinnias are deer-resistant, potentially protecting nearby flowers.

Harvest and Storage

Zinnias typically take 60–70 days from seed to flower (conditions dependent).

Recommended Varieties

• 'Dreamland Series' — full-size flowers on compact plants. Dwarf, fully double flowerheads to 4 inches, wide color range; stems 8–12 inches.
• 'Thumbelinia Series' — dwarf, spreading, single/semi-double weather-resistant flowerheads in many colors. Petals 1¼ inch, stems to 6 inches.
• 'State Fair Series' — biggest, tallest: large double flowerheads 3 inches across, stems to 30 inches.

Wit & Wisdom

• Small narrow-leaf zinnias make nice dried flowers.
• Zinnias symbolize thoughts of absent friends. Learn more flower meanings.