Zinnias are the Anne Boleyns of the garden: They love to lose their heads. As long as you keep cutting stems for arrangements, they'll keep blooming profusely in a rainbow of colors up until an autumn frost.
LIGHT: Full sun
SOIL: Moist, well-drained
FERTILIZE: Every two weeks with liquid blossom-booster fertilizer
They're also the easiest annuals to start from seed. And you don't need a seed-starting kit. Heck, you don't even need a pot. Just find a bare patch of soil in a sunny spot, tear open a seed packet, scatter these large seeds over the surface, rake the soil very lightly, and then water.
The seeds will sprout within a week. Even though it's about midsummer, you still have time to grow flowers for late summer and fall. When seedlings are a few inches tall, thin them to 10 inches apart so each plant has enough room. Crowded plants can mildew and develop leaf spots.
Did I mention zinnias attract scads of butterflies and hummingbirds? You're sold, I can tell. Drooling gives you away.
Zinnia blooms consist of two types of flower—a yellow "disc" flower in the center that forms seed, ringed by a larger "ray" flower for show.
Making the Right Cuts
For the longest-lasting, most beautiful show, snip flowers that are just beginning to open. In early morning, cut stems 12 inches long, place in water, and take inside. Fill a vase with water to which you've added floral preservative. Strip any leaves that will touch the water. While holding the cut end of each stem under water, clip another half-inch at an angle—to prevent air bubbles that block water intake—then arrange. Replace the water and preservative every two days. You can also insert cut stems into wet florist foam. That's less trouble, but the flowers probably won't last as long.
The Go-To Seed Source
Renee's Garden offers a wide variety of zinnia seed mixes selected for long stems and showy blooms. Find Renee's Garden seeds at garden centers or online at reneesgarden.com.