The other evening a friend and I were sitting on my deck having a happy hour and enjoying my gardens. The backyard is literally filled with flowers, many of them the new, must-haves touted in all the gardening magazines. (I grow them to see how they really stand up to our harsh, Midwest summers.) Taking in all the choices in all the different beds, she asked me which flower was my favorite. When I gave her my answer her expression said it all – Zinnia was not the right answer.
Zinnias have a bad reputation. By the uninitiated, they are constantly maligned as prickly, mildew carrying misfits flaunting a mix of garish colors that don’t fit into any modern garden design. According to their detractors, zinnias are a part of the past that should be left there.
I beg to differ. To me, Zinnias, with all of the varieties on the market today, are the foundation pieces of a vibrant, pollinator-friendly garden. They come in every color imaginable (except blue). They are a reliable, easy, no-fuss plant to grow. Pollinators of all types love them. Deer and other critters avoid them. They are long-lasting as a cut flower and you can depend on them to give you beautiful blossoms even as others fade away. What more can possibly you want?
Of all the flowers I grow, zinnias are by far the easiest. They are not fussy about soil type – in my garden they are in thin, rocky clay-based soil.-- but they do want good drainage. Unless the soil is completely devoid of any and all nutrients, they don’t require periodic feedings of fertilizer.
They do however, demand sun. Six hours of full sun is their absolute minimum requirement, but more sun every day is even better. The soil itself must also be warm for zinnias to flourish. Make sure that all danger of frost has passed before planting either seeds or starts. Cold weather can stunt or even kill young zinnias.
Newly planted or newly emerging zinnias require consistent moisture until they are well established. Then, they are reasonably drought tolerant, so water zinnias only when they need it. (Keep in mind that plants wilt during the heat of the day to conserve moisture. A wilted plant is not necessarily a thirsty one.) 
When you do need to water, slowly soak the ground at the base of the plants, and try to avoid splashing water on the leaves. Also, water early enough in the day so that the plant has time to dry off before the evening hours set in.
For zinnias, spacing is critical. 
When planted too close together, especially in humid environments, many zinnia varieties will develop powdery mildew on their leaves. Although unsightly, the mildew usually doesn’t affect the plant’s ability to produce blooms. Keeping plants six to eight inches apart can help slow the spread, but may not stop it.
While there are more than 20 different species of zinnias, four are usually seen for purchase. They are:
Zinnia elegans which is known for its huge range of gorgeous plants and blooms. Many of the Z.Elegans cultivars are tall with large-headed blooms that make excellent cut flowers.
Zinnia haageana and Zinnia marylandica have smaller blooms and tighter, more compact plants than Z.elegans and are often seen filling in the middle section of cottage gardens.
Zinnia angustifolia which is a narrow-leaf, creeping zinnia often called the Mexican zinnia, is a good choice for the front of the bed. Each species is different and each has something unique to offer.
Even though there are many cultivars of zinnias on the market today, they all fall into one of these three categories.
- Single Flowered has a single row of petals and the center is fully exposed and visible.
- Semi-Double Flowered has several rows of petals. The center is somewhat exposed but visible.
- Fully Double Flowered have many rows of petals. The center is not visible.
Zinnias are one of the best options you can add to a pollinator garden. 
They attract honeybees, bumble bees and dozens of types of solitary native bees. Native wasps often stop for a nectar break. Moths are drawn to zinnias, as are multiple varieties of butterflies such as swallowtails, monarchs, painted ladies and admirals to name just a few.
Hummingbirds can be seen visiting patches of zinnias and small birds will search spent blooms looking for seeds. Lady beetles love them, which helps keep aphids at bay.
A quick search of the internet will bring up articles that advise using only single-flowered, open centered zinnias to attract pollinators. For several years it has been a widely held belief that flat headed, single blooms made it easier for pollinators to access nectar. 
Newer research, both anecdotal and controlled, is finding that pollinators do not limit themselves to one type or color range; they gather nectar from a wide variety of flower forms and colors. 
Researchers have also found that flowers that are attractive to pollinators one season may be ignored the next. That opens up new questions to be explored, but also gives you the freedom to plant any zinnia you like knowing that the pollinators are still being well-fed.
It took some time (and a few glasses of wine) for her to understand why I love zinnias, but I think I must have convinced her. We're going to the garden center tomorrow!
