When It Comes to Annuals, Zinnias Are a Great Pick

As you may realize I rarely write about annuals in this column. I don’t use them in my gardens, and for many years I’ve downplayed annuals simply because they are, well, annuals. Yes, I know that few share my philosophy here. And yes, many to most garden designers use them in their designs. But if you want a garden that requires as little maintenance as possible, you may not have too many annuals.

But when I turned on one of my computers this morning the first ad that popped up was from a seed supplier promoting, yes, you guessed it, an annual. And not just any annual. This one is all the way at the end of the alphabet, and I do have to confess, zinnias do have a home in many gardens for many reasons. Add the fact that there is a perennial zinnia and that the annual types are so versatile that this week (and next) we’ll consider this plant for your garden including where it belongs and why.

As with most garden plants, you can simply buy your zinnias as cell packs or in small pots at your local garden centers, but your choices will be limited. On the other hand, if you start your own from seed they can be sown directly into the garden or started indoors and you get exactly what you want, not what the merchandisers think you want. Seeding indoors takes place from late March onward. When started too early they can get leggy and will do poorly in cold outdoor soils.

I’d never put these plants in the ground any sooner than mid to late May, and that’s also the best time to do sowing in situ — in the spot where you want the plants to grow in the garden.

However, if you want the best choices in types and varieties, now is the time to peruse your catalogs or online seed sources and buy that seed. The seed is large, easy to handle, for kids, adults and seniors, and the seeds germinate fairly quickly in soil (indoors or out) that’s over 70 degrees. So, step No. 1? Get your seeds.

From the late 19th century through the late 20th century, zinnias were the flowering annuals of choice for spreading glorious colors throughout the garden as well as for cutting to bring indoors. The plant is especially welcome during periods of drought as it’s native to parts of the world where water is often scarce. But the zinnia was not always prized for its beauty. When the Spanish first saw zinnia species in Mexico, they thought the flower was so unattractive they named it mal de ojos, or “sickness of the eye.” Needless to say, things have changed, and the flower’s colors, plant sizes and disease resistance have also come of age.

There are more than a dozen species of zinnias, which are in the daisy family, but only three species are usually grown in the garden. All three are annuals and bloom from early summer through the first frosts of autumn. Zinnia elegans, known as the common Zinnia, is very familiar to gardeners; varieties — tall, medium and dwarf — have been in the garden for decades, and the flowers are available in just about every color except blue. Z. angustifolia is less known but gaining in popularity. This plant has narrower foliage and smaller single flowers. The species has golden-orange flowers, but the variety “Crystal White” has pure white blooms with yellow centers. “Crystal White” is also more compact than the species, which can spread to two feet.

Probably the least known zinnia is Z. haageana, or the Mexican zinnia. It is remarkably disease resistant, grows to 15 inches and has small, bicolored flowers. It’s an excellent cut flower because of its long and sturdy stems.

Even after seeds of zinnias were sent back to Europe in the 18th century, the plants were not much to look at. It wasn’t until the 19th century that breeding gave it a touch of class. The breeding was done in Germany, Holland and Italy, the strains “Mammoth” and “Striata” were developed as well as the popular “Pumila Mixed” that led to the “cut and come again” types that are still available. But in this country, zinnias really didn’t become popular until the 1920s when Bodger Seeds introduced the giant dahlia types. Shortly thereafter the flat-flowered “California Giant” type was offered, and for the first time a flower was sold in separate colors — considered a new and important trend in American gardening.

The first tetraploid zinnia, “State Fair” came from Ferry Morse Seed Company in the 1950s, resulting in larger plants with stronger stems, more vigorous growth and better disease resistance.

F1 hybrids, the cream of the crop, were harder to come by because of difficulty in manipulating the reproductive parts of the plant that had to be hand pollinated to produce seed. Then, quite by accident, a grower at Burpee found a plant in the field that had a flower with no petals and all female reproductive parts. This plant led to the dwarf F1 hybrid “Peter Pan,” which is still a popular variety.

The most recent zinnia introductions are a result of the interspecific (cross species) crosses of Z. angustifolia and Z. elegans. They represent the best of both: heat and humidity tolerance, disease resistance, easy maintenance (no deadheading) of the 2-to-3-inch flowers and compact growth of 12 to 18 inches.

One of the reasons for the popularity of the zinnia is the diversity of its forms. Like dahlias and chrysanthemums, zinnias have a variety of flower forms and may be single, semidouble or double. Single-flowered zinnias have just one row of petals, and the center of the flower is exposed. Z. angustifolia “Crystal White” is a good example. Double-flowered zinnias, with so many rows of petals that the center is hidden, have several shapes. There’s beehive, with small blooms with rows of flat petals, such as “Small World Cherry,” which really do look like little beehives. Button-type flowers are similar to beehives except the flower is flatter. The edges of each petal on cactus-shaped flowers roll under and the petal twists and bends. The petals on dahlia-flowered zinnias are large and flat and usually semi-double, which means the flowers have many rows of petals but the center can be seen. These are great to use as cut flowers.

Zinnias also have an amazing number of colors. In fact, flowers come in almost every shade but blue. Most are solid, but some, in particular Z. haageana, are bicolored with a contrasting color at the tip of each petal. You’ll find yellow, orange, cherry, pink, purple, scarlet and white as well as one unique chartreuse variety called “Envy.”

Height is an important consideration when planning a garden and zinnias have growth habits to suit every need in the garden. The tall, 3-to-4-foot varieties are best for the middle and rear of the garden or border and in a cutting garden. Dwarf plants grow 8 to 14 inches tall and do well in pots as well as in the front of the garden. Z. angustifolia plants reach 8 to 15 inches in height with an equal spread; they are excellent in the ground, in pots or hanging containers and as summer-flowering groundcovers.

Before going further, I can’t resist writing about the perennial zinnia, or Zinnia grandiflora. This plant is native to the American Southwest and is also known as the Rocky Mountain zinnia. Looking at its native habitat though and the fact that it’s documented being hardy down to zone 5 I do wonder if it would be an interesting plant out here. It clearly wouldn’t do well in most gardens because it likes to grow lean and dry once established, but I do wonder if it would adapt to growing in the sandy soils of gardens along the barrier beach areas and along the sandy, rocky and quick draining soils around Peconic and Shinnecock bays?

If you’d like to try this in your seaside or bayside garden you can get seed from superseeds.com and plants from highcountrygardens.com. The seeds can take several weeks to germinate so you can start them in March, and if you are buying plants have them shipped in mid-May and harden them off before setting them out.

For now though, take a look at the seeds available and get your order in. Keep in mind that you’ll find plants that will grow to only a few inches tall to the cutting varieties that can get 2 feet tall and taller. Due to our high humidity out here, mildew-resistant varieties are also suggested. The plants are also somewhat, but not totally, deer and rabbit resistant. There are many varieties (especially the taller singles) that are pollinator friendly and will attract bees, butterflies and hummingbirds. More next week. Keep growing.

GARDEN NOTES

We’re now entering the coldest and potentially snowiest part of winter on the East End, and your garden may need some attention.

When the ground is frozen solid it’s time to add a winter mulch. This keeps the soil cold or frozen and minimizes the effects of the strong and warm sun melting the soil around some plants that are prone to heaving — getting pushed out of the soil as the ground goes through the freeze-thaw cycles. The crowns of fall-planted perennials can be protected with mulches of pine needles, hay or leaf mulch. Some roses may also be subject to heaving and these should also be lightly munched if only to keep the sun from warming the soil around the plants. Garlic can also be lightly mulched as can asparagus plants, but you need to remove the mulch from the asparagus early to keep voles from digging and snacking on shoots dormant near the soil surface. Fall-planted fruit trees and bushes (strawberries included) will also benefit from a light hay mulch.