Zinnias are among my favorite flowers in the garden

  • Monarchs love zinnias for their nectar.

    Monarchs love zinnias for their nectar. Courtesy of Diana Stoll

By Diana Stoll
Updated 5/19/2020 6:39 AM

My summer gardens would not be complete without zinnias. These old-fashioned favorites bloom in a rainbow of bright colors all summer long, are among the easiest annuals to grow, provide an endless supply of cut flowers for seasonal bouquets and attract birds and butterflies to the garden.

You can purchase zinnia plants at garden centers, but they are also easy to grow from seed. Zinnias thrive in summer's sun and heat so choose a site accordingly and wait until all danger of frost has passed before planting.


Prepare the soil before planting seeds by working in organic matter until it is fine textured, making it easy for developing roots to spread out in the soil. Press seeds one-half inch deep and 3 inches apart in the worked soil. Keep the soil moist until the seeds germinate. As they grow, thin seedlings so plants will be spaced according to the variety planted. Smaller types need just 6 to 12 inches between them; larger varieties need up to 2 feet of elbow room.

If you are purchasing small plants, prepare the soil with organic matter before nestling plants into the garden at the same depth they were growing in their pots. Space them according to the directions on their label. Sprinkle some slow-release fertilizer formulated for blooming plants around each plant and water thoroughly.

Don't crowd zinnias. Adequate air circulation around plants reduces the chance of powdery mildew. Overhead watering should also be avoided or done early in the day, so foliage and flowers have time to dry before nightfall.

Deadhead spent flowers to encourage the most repeat blooms and to keep plants bushy.

If you want to save seed to plant again next year, stop deadheading in late summer. When the flowers are completely dry, seed is easy to harvest. Save them in a sealed container in a dark, dry spot inside for the winter.

by signing up you agree to our terms of service

There are three main types of zinnia flowers: single, double and semi-double. Single-flowered zinnias have one row of petals around a distinctive center. Doubles have so many rows of petals the center is hidden, and semi-double zinnias are in between singles and doubles, but the center of flowers can still be seen.

The Dreamland series of zinnias offers small plants, just 8 to 12 inches tall, but large double flowers in a wide range of colors.

The Magellan series features compact plants and flowers packed with petals. Perfect for the front of the border, Magellan Orange displays large, fully double orange flowers.

Hot Crayon Colors is a mix of intense shades of orange, golden yellow and red. Cool Crayon Colors is a lovely blend of lavender, pink, rose and white.

The Profusion series is an outstanding performer with excellent heat and drought resistance. Profusion Cherry is smothered with cherry red daisy flowers with yellow centers.

Zahara zinnias feature large, nonstop blooms in wide range of colors. Double Fire has fiery orange-red flowers that light up the landscape. Double Cherry boasts magenta blooms with centers that lighten as the flowers age. Starlight Rose sports white daisy flowers streaked with rose and yellow centers.

The State Fair series shows off the tallest zinnias with large, double blooms.

• Diana Stoll is a horticulturist, garden writer and speaker. She blogs at gardenwithdiana.com.

Article Comments ()
Guidelines: Keep it civil and on topic; no profanity, vulgarity, slurs or personal attacks. People who harass others or joke about tragedies will be blocked. If a comment violates these standards or our terms of service, click the X in the upper right corner of the comment box. To find our more, read our FAQ.