This is the time of year when the stone fruits—the peaches and plums and apricots and almonds—are in full flower. The various shades of pink and white petals, some with splashes of burgundy, are brightening many a back yard with the promise of sweet fruit—or sweet seeds, in the case of almonds—that will mature anywhere from June through August.
They’re not as commonly grown in the lower desert cities as they are in more rural areas at slightly higher elevations, mainly because of their lack of the proper city-fied look and the overbearing watchfulness of the local HOA, I suppose. But from a purely horticultural (and apolitical) point of view, they will grow all the way down into the 1000-2000 feet elevation zones or lower. Why? Because they are considered “low chill” fruits, meaning they don’t need to experience an excessive number of cumulative hours below 45 degrees, sometimes as little as 500, to break dormancy. By contrast, other familiar fruits like the more cold-loving cherries and most apples and pears need 700-1000 chilling hours. There are two low chill apples, however, that like it hot, namely the cultivars ‘Anna’ and ‘Golden Dorsett’. And, as you might suspect, they flower about the same time as the stone fruits. Ditto for ornamental pears, though they don’t produce a fruit worth eating.
Schnepp’s Farm in Queen Creek is at 1400 feet elevation and it produces a boat load of peaches every year. If they can do it, so can most other areas in the Phoenix metro area, and certainly in Tucson, which is the same elevation as the Arboretum.
The biggest issue for all of these early flowering trees is the danger of frost, which, of course, is more of a hazard at higher elevations than lower. Last year, for instance, there wasn’t a single plum on the Arboretum’s ‘Santa Rosa’ plum across from the Herb Garden (an area where cold air is known to pool), nor was there nary a purple fruit to form on my ‘Santa Rosa’ plum tree at 1000 feet higher in Globe. This year—as of this writing—the prognosis for warm March nights signals a promising harvest, but ya never know.
The common edible fig, Ficus carica, has one of the lowest chilling requirements of any of the commonly grown tree fruits, with just 100-200 chilling hours needed. The same goes for pomegranates. The quince is also a low chiller, but who the heck eats those? Citrus goes without saying; its chilling hours requirement is a big fat zero.
The photos below were all taken this year, mainly at the Arboretum, and show the subtle differences between the flowers of many of the fruits that I just discussed. Because they all flower before they leaf out, it’s hard to tell which tree is which during the flowering period. Just going through the exercise of photographing them has helped me to better ID them by their flowers, particularly from afar. From up close, the bark types show fine, but distinctive characteristics if you stare at them long enough. After the leaves come out and the fruit begins to attain some size, well, by then, it’s a no brainer.