Although it’s a member of the zinnia family, the desert zinnia (Zinnia grandiflora) is remarkably different from the large annual flower we typically think of when we hear of a zinnia. Actually a member of the aster (Asteracaea) family, this tiny perennial is a delicate xeric groundcover or low shrub native to New Mexico, Arizona, Colorado, Kansas, Oklahoma and Texas.
Also called prairie zinnia or Rocky Mountain zinnia, the plant blooms in summer and its tiny, needle-like foliage dies back in the frost of winter, resembling dormant grass. But have no fear! The plant is there, and comes back, even spreading. I just brush up the dormant leaves as part of the spring garden clean-up, and new plants already are appearing underneath. You could also gently rake up the spent foliage in larger areas. Clearing off the old leaves exposes the new plants to more sun, which they love.
But although desert zinnia loves sun, it doesn’t love water. That’s right – once established, desert zinnia needs no water at all. Too much water just introduces weeds into the mix, which can be hard to pull from between the delicate foliage. If you have a period of no rain, you can give desert zinnia some water to ensure blooming. The flowers also do fine in partial shade.
Typically, the desert zinnia is about 4 inches high and spreads to nearly 15 inches wide. Each flower can reach nearly an inch in diameter, with an orange cone (Golden Eye) surrounded by three to six yellow petals. It should thrive in zones 5 through 8. It’s a great plant for erosion control and for rock gardens. I love how it cascades over and through our rock wall.