Adiós Oleanders?

To go along with the EcoQuest theme, project member @tommygatz was kind enough to share an article about oleander that he had written for The Garden Corner newsletter. It includes some great information and planting recommendations. Check it out! :)

THE GARDEN CORNER
ADIÓS OLEANDERS?

We desert gardeners are a funny lot. We often purchase and pamper plants that struggle to survive here yet we sometimes get bored with the ones that thrive. Enough of us apparently got so tired of the yellow flowers on many of our desert natives that Carrie Nimmer developed a gardening class at the DBG called “Anything But Yellow”. Another example is our love/hate relationship with the oleander that may soon end if a bacillus spread by an insect called the Smoke Tree Sharpshooter eliminates this infamous plant from our town, as it is doing right now in some parts of California and central Phoenix.

Although noted plant expert Mary Irish is the only person I know brave enough to publicly admit to liking the oleander, more than a few of us secretly appreciate its usefulness in giving us privacy from our neighbors, shade for our homes and colorful blooms all summer long. All of this in spite of our ongoing struggle to constantly trim this hedge from hell when we plant it in a spot too small for its eventual size. Although it is not native and is poisonous, it does thrive in hot sun on limited water, stays green all year, flowers all summer, has few pests (until now), and (except for dwarf varieties) survives our winter frosts. I once asked DBG horticulturist Kirti Mathura why we hate it so much. “Because it is over-used and because it is so often planted in the wrong place where it becomes a nightmare to keep in bounds” she said wisely.

Well, what do we do now? If it disappears from the Valley, the Plant Hotline at the DBG will be ringing off the hook with inquiries as to suitable replacements for this landscaping mainstay. Here are several evergreen replacements to suggest, and all are native to Arizona. The following species can be planted together for more diversity. All require well-drained soils. They are all fairly cold-hardy and are susceptible to few pests or diseases. They are all low to moderate water users that can be grown as large shrubs or planted in dense groupings to create a privacy screen, sound muffler, wind break or shade hedge. While they lack the summer-long show of flowers provided by the oleander, they all make an excellent background for colorful annual or perennial plantings. They grow much more slowly than do oleanders, so get them started soon!

Hopbush (Dodonaea viscosa). Full sun. Moderately fast growing to 15 feet tall and 12 feet wide. Its winged fruit can be attractive. There is a purple variety from Australia that is less frost-hardy (to 20F) than our native bright green version. Holds up well in alkaline soils. We have two that shade the west side of our house and provide nesting habitat for our resident Inca doves. Quail and dove eat the seeds. Accepts varying water schedules and grows accordingly. It can be left unpruned and natural or pruned to maintain dense growth.

Arizona Rosewood (Vauquelinia californica). Full sun. Slower growing than the hopbush, this is another great choice for a hedge that can eventually reach 20 feet in height by 15 feet wide with extra water. It has clusters of white flowers and birds love the fruit. Deep water twice a month in summer once established. Develops fullness without pruning.

Sugarbush (Rhus ovata). Does best with some afternoon shade. Large, waxy green leaves with vanilla fragrance; small white flowers and red berries that birds relish. Grows slowly to 15 feet tall and 15 wide. Sensitive to over-watering in the summer. Water every 2 weeks during hottest periods, but allow it to dry out between watering. Best if planted in fall. Little pruning needed.

If you want a prickly barrier, two species worth considering are the thorny Desert Hackberry (Celtis pallida), 12 feet tall and wide (full sun; needs water in summer to stay green) and the spiny-leafed, 10 foot tall and wide Red Barberry (Berberis haematocarpa). Both provide berries attractive to birds. The Jojoba (Simmondsia chinensis) is slower growing to 8 feet tall and 10 feet wide but with friendlier foliage.

Most of these species will be available at the DBG Plant Sale this fall. Thanks to Mary Irish’s “Arizona Gardener’s Guide” and Judy Mielke’s “Native Plants for Southwestern Landscapes” for much of this information and to Cathy Babcock, Angelica Elliott, Dana Hiser, Mary Irish, Ray Leimkuehler, and Kirti Mathura for reviewing earlier drafts of this article.

Tom Gatz The Garden Corner (@tommygatz)

Posted by jenydavis jenydavis, July 22, 2021 17:50

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