If you are struggling with a hot and dry area that requires a major dose of color, Rocky Mountain zinnia can come to the rescue! This long-blooming perennial is a rugged native located in the arid slopes and mesas of the southwestern U.S., but is sorely underused in garden settings.
Jocelyn H. Chilvers
Botanical name:Zinnia grandiflora
Common names: Rocky Mountain zinnia, prairie zinnia, desert zinnia
Origin: Native to the southwestern United States, Mexico and Central America
Where it will grow: Hardy to -30 degrees (USDA climate zones 4 to 7; locate your zone)
Elevation range: 4,000 to 6,000 ft
Water requirement: Very low
Light requirement: Total sun
Mature size: 6 to 8 inches tall and 10 to 15 inches broad
advantages and tolerances: long blooming — June to freeze; very drought and heat tolerant; deer and rabbit resistant
When to plant: Spring
Seasonal curiosity: Rocky Mountain zinnia flowers prolifically from June to frost (the photographs here were taken from early July and early September).
Jocelyn H. Chilvers
Jocelyn H. Chilvers
Distinguishing attributes. The 1-inch-diameter blossoms feature bright, golden-yellow petals and dark orange anthers. The foliage is nice, with needle-like leaves in a cool blue-green colour.
The best way to use it. Plant Rocky Mountain zinnia as a showy drift of bright color in prairie gardens, xeriscape gardens and desert gardens. Blend it with drought-tolerant, short, native grasses, like blue gramma grass (Bouteloua gracilis, USDA zones 3 to 10) and buffalo grass (Bucheloe dactyloides,zones 4 to 9), and wildflowers like purple prairie clover (Dalea purpureum, zones 3 to 9), wild four o’clock (Mirabilis multiflorus, zones 4 to 8) and orange butterfly weed (Asclepias tuberosa, zones 4 to 9).
A high drought tolerance and nice foliage feel also make Rocky Mountain zinnia an perfect foil for rocky plants like Yucca spp (as shown here), Hesperaloe spp, Agave spp and cacti.
Jocelyn H. Chilvers
Planting notes. Rocky Mountain zinnia demands well-drained soil — sand or sterile clay — and a bright website. Water young crops to establish the root system, then decrease or remove water altogether. (Mature plants will endure with 6 to 8 inches of water each year.)
The plant tends to gradually spread through rhizomes (specialized underground stems) to form a massing earth cover. It may also spread by seed; deadhead the flowers at the end of the growing season to control dispersing if necessary.
Notice that the crops are extremely late to break dormancy and won’t show in the garden before the soil warms up in spring or early summer.
More: What to Do in Your Garden Now