Desert plants are challenged by hot and arid growing conditions. Water-wise gardening addresses their water needs and defines the best growing locations. But how can we be more confident that the timely pollination needed to set seeds, fruits, or nuts is accomplished? The answer is desert native bees, master pollinators of desert plants.
The estimated 1,000 species of native bees that call the Sonoran Desert their home have co-evolved with desert plants for eons. The specialized adaptations developed over that time provide desert native bees with advantages that assist in their food gathering and boost the associated pollination services. So, to ensure the timely pollination of our desert plantings, we need to nurture desert native bee populations.
This is best done by increasing the availability of flowering plants preferred by desert native bees and expanding their habitat. Even small (and minimal cost) changes can make big differences in desert native bee populations, so it can be done. But before we explore that topic, let’s examine a shortlist of common bees you’ll see frequenting your garden and nearby wild areas.
Western (also known as European) honeybees were introduced by the first Spanish colonists. These bees are social (living as colonies in hives) and can sting individually or as a swarm. Their ability to inflict pain creates, in many people, a fear of all bees. That is too bad, as most of our native desert bees you will encounter do not sting. Plus, honeybees are not aggressive when collecting food for their hive, and swarms with angry intent are rare (although wild honeybees are sensitive to hive disturbance). If you encounter a single honeybee at close range, hold still and savor the chance to watch the bee do her work. It will shortly move on to flowers further afield, as its goal is collecting food–not stinging you!
In comparison to honeybees, desert native bees are most often stingless (no pain) and solitary (no swarms). The notable exception is bumblebees. They have a powerful sting if provoked and will aggressively defend their nest. In a close encounter with a single bumblebee, follow the rules for honeybees. Normally harmless carpenter bees are often confused with bumblebees because both are large. But bumblebees have bright yellow hair bands on their backs while carpenter bees are jet black (a small yellow fuzzy patch may be behind their head, however).
Mason bees and leafcutter bees are widely used as commercial pollinators of orchard fruit and nut crops. But they are common in the wild, as well. Mason bees are efficient pollinators of early orchard blooms and wildflowers. Leafcutter bees follow them, actively pollinating in late spring and early summer. They are best known for the small round holes they cut in plant leaves to use in building their nests.
Miner bees (below) are common summer pollinators. They make their nests underground, often close to many others of their kind. Sweat bees (below right) are common summer pollinators, as well. They can take many colors, normally very bright and metallic. Some sweat bees will briefly land on humans, seeking water and minerals from perspiration. If that happens to you, do not disturb the bee. Just hold still and watch nature in action until she leaves.
Examples of desert native bees that have co-evolved with specific native plants are common. Cactus bees (below left) are one example. They feed almost exclusively on a few cacti species, especially prickly pear and cholla. Squash bees (below right) are another example of co-evolution. They feed on gourds, squash, and pumpkins. Nests are in the ground under the leaves, taking advantage of the shade and cooler temperatures. Males often sleep in larger flowers while waiting for females to hatch.
Look for desert native bees where they are most likely to be in your garden and nearly wild spaces–among flowering plants, orchard trees, and cacti. Expand the number and diversity of bee populations in your garden and wild places by following the planting and habitat guidance below. Because desert native bees have been arid land dwellers for so long, solutions almost exclusively use water-wise plants.
Attracting Bees with Desert Plants
There are three aspects of plantings that best support desert native bees. These are (a) multiple flower colors, (b) varying bloom heights, and (c) blooms available throughout the growing season. As to flower colors, a mix of purple, blue, yellow, or white flowers is preferred. A range of flower heights, from one to five feet, speaks to the unique needs of small and large bees and those with specialized feeding habits. Continuous flowering from very early spring to late fall is needed to support differing life cycles of desert native bee species. Early spring is the most important time to ensure ample flowers because desert native bees are often the most active pollinators in that cooler time. But fall is also vital, as the supply of native flowering plants is limited.
In your plantings, don’t neglect the need for supportive desert native bee habitat. Mainly this can be addressed by simply letting things grow on the wild side. A few weeds are a good idea and have a brushy area or unattended nearby wild spaces to provide shelter. Put out bee houses in later winter for tube nesting bees (e.g. mason and leafcutter bees) and provide patches of loose soil for ground-nesting bees. Providing water, as a drip-fed seep or very shallow pool, is a big help.
A select list of plants for desert native bees is provided below. But anything that flowers will be helpful including many of our native flowering trees. Don’t forget that native or acclimatized food plants, including herbs, can also provide flower food for desert native bees. Absolutely avoid pesticides or herbicides, both on general principles and because bees of all types are unusually susceptible to the ill effects of toxic chemicals.
In the Sonoran Desert, late fall and early winter are preferred times for seed sowing and setting plants that will nurture desert native bees. Prepare garden beds and identify places in wild areas suitable for bee-related enhancements and go to work when the time is right this year. Then, as the next growing season evolves, enjoy your many new flowers and their desert native bee pollinators. You deserve it!
Water – Use It Wisely is proud to feature guest bloggers who write about topics related to water and water conservation. The author of this blog is Dr. William J. McGuire, Ph.D. Bill taught Economics and Finance at the university level for 10 years and worked for five years in the banking sector. He then started his own bank consulting company, focusing on the accuracy of PC-based income simulation and valuation models. Since retiring, Bill now serves on the Board of Directors of Native Seeds/SEARCH, a Tucson-based nonprofit dedicated to preserving and sharing heritage and landrace [one that is customized to a specific growing area and thereby has its own growth habits and taste] native seeds. He is also active in other Arizona service organizations and programs. Bill is an arid lands gardener, desert native bee enthusiast, vintage British car mechanic, and a creative (if not always successful) tinkerer.