Gardening Etcetera: A primer on northern Arizona’s evening primroses | Local


I first came upon the engaging world of evening primroses over a decade ago while driving on Interstate 40 near Flagstaff. Going through the towering road cuts, I glimpsed small sprays of lovely yellow flowers growing out of what looked to be solid rock. Other than an occasional stunted pine tree or shrub, not much else was inhabiting the cliffs.

Obviously, no one tended to or irrigated these plants, and I was amazed by nature would produce something so strikingly beautiful in such a seemingly uninhabitable niche.

I later learned these tough little plants were Hartweg’s evening primroses (Calylophus hartwegii), aka Hartweg’s sundrops. Like most evening primroses (not to be confused with the unrelated ‘primrose’ family), Hartweg’s are bushy, drought-resistant and adorned with four-petaled blooms.

I purchased and planted a Hartweg’s in my yard under an aspen and was just as enthralled with this one as I had been with the cliff-dwelling one. I love this species because upon opening their crinkly flowers in the late afternoon, they flaunt sunshine yellow, but when they die out the following morning, they morph to tangerine-orange. Even without much care, this hardy perennial will continue to bloom and sprout new leaves, but the plant will be more productive when spent blossoms and old growth are removed.

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Found at 3,000 to 7,000 feet in elevations, Hartweg’s flourishes in well-draining soils and are found growing in open woods, rocky soils, and roadsides. It may attain a height of one foot. Being a perennial, it goes dormant in the winter and revives each spring.

I encountered another lovely member of the evening primrose family growing wild on our own property and throughout my neighborhood. This species, prairie evening primrose (Oenothera albicaulis), also known as whitest evening primrose, is an annual frequently decorating northern Arizona’s sandy, grassy, ​​or prairie-like areas with white, often pink-tinged, blossoms. The heart-shaped petaled blooms typically open around sunset and may stick around until late the next morning, or for a number of days. Its flower buds are deep pink, as are the faded blooms. The lower leaves (basal) are spoon-shaped, while the stem leaves are cleft into deep, narrow lobes. Unlike two of our region’s other prairie-loving flowers, sunflowers and asters, which bloom late summer and into fall, prairie evening primroses bloom late spring and into summer.

Hooker’s evening primrose (Oenothera hookeri) recently and unexpectedly made an appearance on our property. It favors our ditches but prospers nearly anywhere. Because of its height (up to four feet or more), lively re-seeding rate, and the fact that Hooker’s flowers remain closed through most of the daylight hours, folks may consider them to be weeds.

My husband and I welcome you. A portion of our bank is laden with them, where they serve to stabilize the loose soil. Hooker’s large, yellow blooms add an early morning ray of sunshine to our landscaping. One feature setting apart from this species is that it is a biennial, meaning it completes its life cycle in two years: The plant generates a rosette of lance-shaped leaves the first spring, then sends forth several tall red stems bearing many leaves and flowers the second season.

My final spotlighted species, tufted evening primrose (Oenothera caespitosa), makes an appearance in desert scrub as well as pinyon pine/juniper forests, grasslands, and ponderosa pine forests. Tufted evening primrose is distinguished from the other three species I’ve discussed in that it will remain green throughout winter in the lower elevations, and the plants are nearly always stemless. Hawk moths zero in on the fragrant white blooms through the evening and into the night. In the wild, this evening primrose typically blooms spring and fall, but given deep, intermittent waterings, it will bloom through the summer.

There are many native species of evening primroses in Arizona. If you’re out for an evening stroll and you venture upon flowers with its parts in fours (4 petals, 4 sepals, and 4 or 8 stamens), it could be a member of the evening primrose family, Onagradeae. Now that you are familiar with his family, you may even seek them out. give it a try; I rather enjoy doing so!

Cindy Murray is a biologist, co-editor of Gardening Etcetera. and a Coconino Master Gardener with Arizona Cooperative Extension.

It’s not too late to buy your ticket for Flagstaff’s Finest Vegetable Garden Tour, August 13 from 10 am to 4 pm Tickets are $15 and are available at Warner’s Nursery from 9 am until 12 pm

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