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Zinnias (Zinnia elegans)

Zinnias - Edible Flower

Zinnias are annuals, so they’ll grow for one season and produce seeds, but the original plant will not come back in subsequent years. They have bright, solitary, daisy-like flowerheads on a single, erect stem, which makes them great for use as a cutting flower or as food for butterflies.

There are three main kinds of zinnia flowers: single, semi-double, or double. The distinction between these forms comes from the number of rows of petals and whether or not the center of the flower is visible:

  • Single-flowered zinniashave a single row of petals and a visible center.
  • Double-flowered zinniashave numerous rows of petals and their centers are not visible.
  • Semi-double-flowered zinniasare somewhere in-between, with numerous rows of petals but visible centers.

In addition to these forms, zinnia flowers come in a number of shapes, including “beehive,” “button,” and “cactus.” There’s really a zinnia for every garden!

How to grow

Plant zinnias in an annual or mixed border garden, while smaller zinnias are suitable for edging, window boxes, or other containers. It’s recommended that you grow zinnia from seed right in the garden bed, as they do not like to be transplanted as nursery plants and do not often thrive. From seed, they will grow very quickly in the right conditions.Zinnias are sensitive to frost, so do not seed until the last frost has passed. See your local frost dates. Zinnias will grow in a minimum daytime temperature of about 60°F (16°C), though a range of 74–84°F (23–28°C) is preferred.Sow a round of seeds every week or so for several weeks to extend the flowering period.Zinniasare good companion plants for vegetables and deserve a place in your vegetable garden, as they deter cucumber beetles and tomato worms. They attract predatory wasps and hover flies, which eat insects that would destroy garden plants. They attract hummingbirds, which eat whiteflies before those flies can damage tomatoes, cucumbers and potatoes.

  • Choose a location that gets full sun is essential.
  • Zinnias are adaptable, but the ideal soil is rich in organic matter and well drained.
  • Soil pH should be between 5.5 and 7.5. 
  • If soil is amended with compost, the flowers will grow more quickly. Learn more about soil amendments and preparing soil for planting.
  • Space plants 4 to 24 inches apart, depending on variety. (Many common varieties are planted 6 inches apart within the row and 2 feet in between rows.) See back of seed packet for variety-specific advice.
  • Sow zinnia seeds only ¼-inch deep.
  • You’ll see zinnia seedlings in only 4 to 7 days for most varieties, though it will be anywhere from several weeks to a couple months before blooms appear (depending on planting site and climate).
  • When seedlings reach three inches tall, thin them so that they’re 6 to 18 inches apart to maximize air circulation. This reduces the chance of powdery mildew
  • Maintain moderate soil moisture and fertilize lightly to maximize growth and blooms.
  • After zinnias flower, cut off the old flowers (a process called “deadheading”) to encourage more flowers to form.
  • Zinnias are annuals and will die with the first fall frost. If you want them to reseed, let the last flowers of the season mature fully and scatter their seeds. 

Growing zinnias on the same schedule as tomatoes, zinnias will attract the bees, and the monarch butterflies that migrate south in the fall. Indeed, the parent species of modern zinnias were found in southwestern Mexico, only a few hundred miles from the Monarch ButterflyBiosphere Reserve, where millions of monarch butterflies spend the winter. Monarchs willrecognise zinnias instantly, and always stop for a few sips of nectar.Semi-tropical zinnias need warm conditions to grow well, so wait until late spring to start seeds indoors. Seed germination is usually fast and sure, but then the seedlings need plenty of light to keep them happy. Grow zinnia seedlings alongside tomato and pepper seedlings, which have similar preferences for warm temperatures and intense light.Zinnias need fertile soil in full sun, and varieties that grow more than 60 cm tall and benefit from staking. Un-staked plants that are blown over by storms will continue to produce flowers, but the stems will be short and curved, and more difficult to use in arrangements.

Most zinnias are susceptible to powdery mildew, which is most severe on tired old plants. To make sure to have plants blooming when the monarch butterflies arrive start sowing your zinnia seeds in early summer. Zinnias attract and benefit pollinators; with the zinnias themselves pollinated by insects, typically bees and butterflies. Their bright colors draw pollinators to a garden. Monarch butterflies, in particular, love zinnias and pollinate them and use them for food and egg-laying habitat. Honeybees also benefit from zinnia pollen and nectar.

Health and medicinal benefits

Zinnias are the quintessential sun-loving flowers.Fittingly, the man for whom zinnias are named, Johann Gottfried Zinn, was the quintessential 18th-century botanist-physician. Prior to the era of mass-produced pharmaceuticals, physicians were typically botanists, too, since nearly all medicines came directly from plants. Immediately before he became a faculty member of a medical school, Zinn worked as the director of a botanical garden.Coincidentally, perhaps, zinnias are highly medicinal. Their habitat extends from the American Southwest into Mexico, all the way down through Central and South America.The Navajo consider zinnias a sacred Life Medicine, using their flowers and leaves in herbal remedies for a variety of illnesses. Navajo children are encouraged to eat the flowers to become wise. The flowers are also of value in the manufacture of dyes and paints.In recent years, studies have proved what ancient wisdom always held, that zinnias have beneficial properties. The major beneficial compounds in zinnia flowers include saponins, glycosides, flavonoids, steroids, and phenols.Zinnia has been shown to have antioxidative qualities. This compound is probably part of the reason why the flower was revered by ancient tribes. In a study involving rats with CCl4-induced toxicity, zinnia extracts were shown to have a significant ability to suppress toxicity in the rats. In addition, the extracts seemed to improve the lipid profile of HDL and LDL. Zinnias are also known to have antifungal, phytoremediative, anthelmintic and hepatoprotective properties.

If you are going to use Zinnia to treat an existing health condition please consult with your healthcare provider first.