Zinnias—If You Plant Them, Butterflies Will Come

Grown any zinnias lately? If so, you're in good company. These cheerful annuals are enjoying renewed popularity as more and more colorful, compact, and disease-resistant varieties appear on seed racks. In 1999, Zinnia 'Profusion Cherry' and 'Profusion Orange' were chosen as All-America Selections award-winners. These new, low-maintenance hybrids produce lovely 3-inch single flowers that bloom for months.

Of course, zinnias have featured strongly in American gardens for many decades. Kids love them because they are so quick to germinate and easy to grow. Zinnias excel as cut flowers; their rigid stems hold long-lasting blossoms that don't drop petals. And they are a natural for the butterfly garden, attracting many species throughout their long blooming season.

Native to Mexico and Central America, the genus Zinnia was named after the 18th-century German botanist Johann Gottfried Zinn. During the 19th century, European hybridizers worked on Zinnia elegans, a drab purplish wildflower, to develop brightly colored double forms, such as dahlia-flowered zinnias. The W. Atlee Burpee Company picked up the torch during the 1920s and introduced large cactus-flowered zinnias (named for their resemblance to cactus-flowered dahlias, not cacti).

Plenty of Zinnias

Most of the zinnias on the market are derived from Z. elegans. These garden zinnias have double or semidouble flowers on stiff stems.

Low-growing garden zinnias (6 to 18 inches) bear names evoking the diminutive: 'Thumbelina'‚ 'Lilliput'‚ 'Peter Pan', and Lollipop series. Taller garden zinnias include doubles and semidoubles, such as Oklahoma and Splendor hybrid series, 'Whirligig', 'Sunbow Mix', 'Cut and Come Again Mix', 'Candy Stripe', and 'Envy', a unique chartreuse-green flower. Also among the tall garden zinnias are dahlia-flowered types ('Giant Flowered Mix', Blue Point/Benary's Giant and Border Beauty series); cactus-flowered forms ('Cactus Flowered Mix'); and scabious-flowered varieties ('Scabiosaflora Mix').

If these Dolly Parton blooms aren't to your taste, consider growing old-fashioned zinnias with single, daisy-like flowers. Start with Z. angustifolia (also known as Z. linearis). This flower, favored by the Aztecs, grows in profusion from June until frost on a bushy, spreading plant about a foot high. A great container plant, Z. angustifolia is drought-tolerant and mildew-resistant. Classic Z. angustifolia bears 1-inch flowers with orange petals around a yellow center. The Star series offers orange, gold, or white flowers.

I'm partial to the coppery tones of Z. haageana (also known as Z. mexicana), an easy-care zinnia that performs until frost. The 2-foot tall 'Persian Carpet' bears 2-inch double and semidouble flowers in a riot of autumn colors and patterns. Mahogany petals tipped with gold characterize the 2-inch flowers of 'Old Mexico' (mostly double) and 'Chippendale' (single); both plants grow to about 18 inches tall.

I also like the old-fashioned look of Peruvian zinnias (Z. peruviana, also seen listed as Z. pauciflora), which were favored by Thomas Jefferson. The 1-inch single blossoms of 'Red Peruvian' fade with age from terra cotta to a soft brick red. 'Yellow Peruvian' fades to a soft gold. Both plants reach about two feet tall on stiff stems. (Peruvian zinnias may also be marketed as 'Bonita Red' or 'Bonita Yellow'.)

There are two perennial zinnias native to the Southwest: desert zinnia (Z. acerosa) and plains zinnia (Z. grandiflora). Desert zinnia is a low, spreading plant that bears 1-inch white, daisy-like flowers. Its narrow leaves are evergreen, creating a good ground cover. It prefers well-drained soil that is low in organic content. Plains zinnia, with a similar growth habit, has yellow flowers. It is more tolerant of cold, but it can be difficult to establish.

Butterfly Favorites

Some zinnias are more attractive to butterflies than others. I interviewed some gardeners from around the country to find out which varieties worked best for them. Surprisingly, single-flowered, species zinnias aren't the uncontested favorites.

In eastern Washington, where summers are hot and dry, Patti Ensor found Peruvian zinnias to be only moderately attractive to small butterflies, such as skippers. According to Ensor, they don't hold a candle to the large double 'Cut and Come Again'. With its sturdy landing platform, the latter is a major attraction for Western Tiger Swallowtails, who linger to sip nectar. 'Cut and Come Again' blooms from midsummer to frost, in hot shades of pink, yellow, orange, and scarlet.

Minnesota gardener Cathy Leece devotes a sizeable flowerbed to zinnias of many shapes and colors. Last year, Leece planted single-flowered Peruvian zinnias in expectation of fabulous butterfly viewing. "I was surprised at how tall and branched out they got," she says. "They filled half the bed, crowding out the other varieties behind them. And they didn't attract butterflies."

Blue Point Formula Mix and 'Royal Purple' (a Blue Point zinnia from Park Seed) have been the most popular zinnias in Leece's garden. The latter's big purple flowers, in particular, are a magnet for fritillaries, American Painted Ladies, and Eastern Tiger Swallowtails. Moderately attractive zinnias include giant cactus-flowered 'Sunbow Mix' and Z. angustifolia 'Crystal White' (Park Seed's name for 'Star White'). Leece has found that 'Envy' and, Z. haageana 'Persian Carpet' have not attracted visiting butterflies.

The Star series of Z. angustifolia proved to be most popular in Denise Gibbs's Maryland garden. "'Star White' was the best," says Gibbs, "attracting blues, sulphurs, hairstreaks, skippers, Red Admirals, Painted Ladies, and others. It made a beautiful display, cascading over the edge of a planter on my deck. 'Star Gold' was also attractive, but I saw little activity on 'Star Orange'."

Gibbs also grew Z. 'Profusion Orange' and 'Profusion Cherry'. In spite of their single flowers, they did not attract many butterflies. The very similar Pinwheel series, however, attracted a diversity of species well into October.

Growing Zinnias

Zinnias will reward you with bundles of colorful blooms from early summer until the first frost, provided that you give them rich, loamy soil in a sunny spot. Don't over-water! Zinnias like hot, dry summers. Cut them frequently to encourage branching and to prolong blooming. Resist the urge to line plants up singly as an edging; zinnias are more appealing (to us and to butterflies) as an irregular mass of bright colors. Because each plant forms many side branches, weeds aren't likely to be too troublesome in the zinnia patch.

Wait until after the last frost to direct-seed in the garden, and then remove the weaker seedlings so that plants are 6 to 18 inches apart (depending on plant size). For continuous blooming, re-seed every couple of weeks until midsummer. In cooler climates like the Northeast, starting zinnias indoors will give you a longer flower display. But be aware that zinnias dislike root disturbance. Harden them off gradually by setting flats outdoors for a few hours each day. Transplant carefully after weather is reliably warm, trying not to expose the roots. Water the seedlings upon planting but infrequently during summer. When growth resumes, give them a light application of fertilizer.

The hairy leaves of zinnias are prone to powdery mildew in humid areas and during late summer and fall, when dew is heavy. Space plants to give them adequate air circulation and avoid overhead watering, which spreads the mildew spores. Choose mildew-resistant varieties, such as Blue Point, Oklahoma, Profusion, and Pinwheel series. No one will notice if you have removed infected leaves before filling a vase with an assortment of festive zinnias—certainly not the butterflies, who'll be too busy enjoying the flowers that remain.

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