A number of years ago, horticultural research scientists determined that autumn is ideal for planting any number of plants. Ever since then, we garden writers have been espousing the virtues of fall planting. But beware, like every rule, there are exceptions!
Exception 1: Succulents
Do not plant agave, cacti, yucca or other succulents with the season cooling down.
Exception 2: Plants from tropical climates
How can you tell? By the bark. In general, trees with smooth bark can’t withstand much, if any, frost. They include citrus, figs, palms, desert willows, yellow bells and even our native palo verde trees.
Yes, the title has fruit in it, so now I’ll get to the point. Even with the above restrictions, there are a number of fruit and nut trees you can plant this autumn. Depending on their age and size, and if we have a gentle winter, you may even get a crop next year. You may have read in previous columns of mine about luscious sub-tropical and tropical fruits you could plant. Wait until spring for most of them. But not all.
Guava, one of the ingredients of Hawaiian Punch (passion fruit is another), does well here, if you get the lemon or strawberry guava (Psidium littorale). When mature, these plants survive temperatures in the low 20s.
The tropical guava (Psidium guajava) does not survive below 26 degrees and should not be planted in autumn anyway. A low tree or tall shrub, the glossy evergreen leaves of guava look very tropical and refreshing next to a swimming pool.
Pineapple guava (Feijoa sellowiana) is not a true guava. This dense evergreen shrub will reach 20 feet, perfect to serve as a screen from your neighbors. The delicate white with purple flowers appear on new wood, so excessive pruning denies you the taste of the plum-sized fruit.
It has a unique, sort of a pineapple flavor with a taste of spearmint. This is the hardiest of all the sub-tropicals and will withstand temperatures to 15 degrees.
Nut trees you can plant now include low-chill varieties of almonds, pecans, walnuts and some chestnuts. “Low-chill” varieties need a low number of hours of cool soils and freezing air temperatures, in the range of 100 to 200 hours.
Some high-chill varieties withstand more than 1,000 hours of freezing. Along with low-chill, any tree you select will also need to withstand our searing summer heat. There are varieties for that as well.
Some sources for fruit and nut trees include such long-standing plant nurseries as Stark Brothers in Missouri, as well as some newer nurseries, like One Green World in Oregon and Chestnut Hill in Florida. The latter offer many newer varieties as well as tasty heirloom varieties that were almost lost in the sands of time but now being revived.
Things to consider when ordering
Remember our chilling hours are, in general, under 200 hours. Also, while Tucson is in USDA Zone 9 with respect to frost dates, SaddleBrooke is in Zone 8B. Above all, look for the heat-tolerant varieties. The three companies I mentioned have knowledgeable sales staffs to help you in your selection.
But when it comes time to order, please be patient with them. The State of Arizona has some draconian laws about shipping plants, and the companies have to obey those laws when shipping here, even though they are based in another state.
Edible landscapes provide food while they enhance your landscape and home value. If you have to plant, water and prune it, why not reap the rewards with some fruits or nuts?!
Father Kino imported a number of European fruit and nut trees to our area, but Dr. Jacqueline Soule only addresses the herbs in her latest book, “Father Kino’s Herbs: Growing and Using Them Today” (Tierra del Sol Press, $14.95). The book is available at area nurseries, or email firstname.lastname@example.org for more information.