Salt-worthy flowers are stunning—and sensible

Agricultural Research, August, 2004 by Erin Peabody

For the experiments, the researchers first used high-quality water to establish the plants. Then, the seedlings were irrigated regularly with laboratory-made solutions containing gradually increasing concentrations of salts--chlorides and sulfates of calcium, magnesium, sodium, and potassium. The lab's sand tanks, filled with washed river sand, supported the plants and mimicked the systems used by commercial greenhouses.

Florist Favorites

One of Grieve's first floral subjects was statice, a plant with small, paper-like, blue or lavender flowers. Statice is a staple flower crop, with 3.7 million bunches of it sold in 1998, at a value of almost $4.5 million. An added bonus, its flowers are long lasting, retaining bright, funnel-shaped flowers that often deepen in color when dried. Grieve studied two species of statice: Limonium perezii, cultivar Blue Seas, and L. sinuatum, cultivar American Beauty.

"In much of the literature, statice is said to be halophytic, or salt-loving," she says. "And its native environments include sand dunes and beaches. So I was surprised it didn't do better."

Both species of statice were able to complete their life cycles under highly saline conditions. But stem length and other qualities important for floriculture production were diminished. The researchers found Blue Seas to be salt sensitive and American Beauty to be only moderately salt tolerant.

Grieve notes that this finding shouldn't preclude use of the two cultivars in other horticultural settings. "While these statice plants weren't able to obtain optimal growth under highly saline conditions, both have great value as bedding or landscape plants in problem areas," she says.

Another flower found in almost all flower shops, and commonly spotted in perennial gardens, is stock, or Matthiola incana. This plant, with its stalks of small, bunchy flowers, is known in the industry for its spicy-sweet fragrance.

Grieve put two different stock cultivars, Cheerful White and Frolic Carmine, to the salt test. Like statice, the stock studies revealed the unexpected. "We found stock to be surprisingly salt-tolerant, contrary to what was previously known about it," she says.

The ability to produce stock with a less-costly, saline water source should be good news for California stock growers, who supplied the country's florists with 24 million stems of the flower last year.

Traditional and Exotic

Bright and bold, sunflowers are native to North America and often sold at farmer's markets across the country. Grieve studied two different ornamental sunflower cultivars, Moonbright and Sunbeam, and found that excess salts didn't affect the diameter of the flowers. Her test waters were typical of those used for irrigation in the Coachella Valley, where sunflowers are grown as a field crop.

"The saline conditions did affect stem length," says Grieve. "But the size of the salt-stressed sunflowers, 4- to 5-inch heads on 28- to 30-inch stems, makes them completely acceptable for the bouquet market."

The genus Celosia, of the amaranth family, offers blooms that satisfy the florist or gardener who's looking for a more unusual plant. Grieve, along with halophyte biologist Christy T. Carter, studied Celosia argentea, var. cristata. Its velvety, oversized flowers are crinkled, suggesting the wavy surface of brain coral.