August has rolled around, and with it, the dog days of summer. If your garden is anything like mine, it’s starting to show a little wear and tear, responding to some extreme summer heat and drought. The bloom is off my roses — literally — and most other flowers in the garden are a little crispy around the edges.
Everything, that is, except the zinnias.
Zinnia flowers are one of those rare blossoms that not only laugh in the face of heat and drought, but also put on such a colorful, glorious display, the rest of your summer garden will be embarrassed. Their large, petaled faces come in all shades of pink, yellow, orange, red, and purple, making a garden loaded with zinnias look like it’s full of large, colorful lollipops. And the pigments are so rich and clear — it’s exactly what the eye is searching for on a sweltering August day.
This bold annual has been in cultivation for hundreds of years and originates in the southwestern United States, Mexico, and Central America, which explains why it’s such a great performer in hot, sunny locations in the garden. Flowers last for such a long time in pristine condition that zinnias are sometimes known by the common name “Youth and Old Age.” Gardeners have a great sense of humor, don’t we?
Look around and you’re likely to see zinnias everywhere in a garden, starting at the front of a garden bed at 6 inches tall, all the way to the back, standing at a stately 4 feet tall, and everything in between.
You can start zinnias by seed indoors 4-6 weeks before the last average frost date for your zone, or wait and sow them directly in the garden when the weather warms. It’s an incredibly easy plant to grow from seed — great for children and beginning gardeners — and I’ve even had zinnias sow themselves from seed that appeared on stems from the previous year. Or stop by your local garden center and pick up a six-pack or two. In fact, I plant zinnia seed directly in the soil successively every two weeks in patches at Moss Mountain Farm (Zone 8a) as a late as August; always ensuring plenty of blooms in early fall and through October.
The only disease issues to keep an eye out for are possibly leaf spot and powdery mildew. The main culprits are too much water, high humidity, and poor air circulation. During the height of summer, water at the base of the plants so that leaves remain dry, and let them dry out between waterings. Pick up and discard brown, fallen leaves, and space plants so that there’s enough room for good air circulation. If necessary, treat affected plants with a fungicide, such as Neem oil.
But honestly, I think the zinnia’s overwhelming flower power is enough to overcome any spots or blemishes you might encounter.
Some Favorite Zinnia Varieties Include:
- Zinnia elegans ‘Cut and Come Again’ — These 3-feet-tall double flowers feature blooms about 2-1/2 inches wide. And as you might guess, they make great cutting flowers, producing new flower buds throughout the growing season.
- Zinnia elegans ‘State Fair’ — The classic zinnia and my gold standard variety. Plants reach about 2-1/2 feet tall, and flower heads are an amazing 5-6 inches across. You can see these blooms from a mile away.
- Zinnia elegans ‘Benary’s Giant’ – The go-to zinnia for the cut flower industry, ‘Benary’s Giant’ has luscious, dahlia-type flower heads and extra sturdy stems. Plants reach about 3 feet tall, with blooms 5 inches wide.
- Zinnia elegans ‘Magellan’ — Considered a dwarf variety, ‘Magellan’ reaches 12-14 inches tall, with double flowers. This variety has a tidy, uniform growth habit, so is perfect in containers and window boxes.
- Zinnia elegans ‘Thumbelina’ — A true dwarf at only 4-6 inches tall, ‘Thumbelina’ is a great selection for the front of the border or as part of a container planting display.
- Zinnia marylandica ‘Profusion’ — Exceptional disease resistance and a compact, uniform habit make this another really popular variety. Plants reach about 18 inches tall and can spread to about 18 inches wide. These qualities make this variety a great selection for garden planting en masse.
- Zinnia angustifolia — Also known as creeping zinnia, this plant features narrow leaves and is often used at the front of the border, reaching about 12 inches tall. Z. angustifolia is even more robust than Z. elegans, so you’ll often see it in mass plantings.
This is just a small sampling of the many zinnias available, and there are new varieties being introduced every year. Just let some of the names entice you: Whirligig Mix, Peppermint Stick, Red Spider, Queen Lime with Blotch, Persian Carpet, and Raggedy Ann. My fingers are twitching for a seed catalogue, and I hope yours are, too.
By P. Allen Smith
P. Allen Smith is one of America’s most recognized garden and design experts. His Moss Mountain Farm serves as a place of inspiration, education, and conservation. Book tours at pallensmith.com/tours.