Ah, spring is in the air – and unfortunately so is the pollen that makes so many miserable. The main culprits for allergy-causing pollens are those that are airborne.
Plants have developed several ways of distributing pollen. If a plant has a large brightly colored flower where the stamens are easily available, then the flower is most likely pollinated by butterflies or bees. If the plant has a slender tubular flower, it is most likely pollinated by hummingbirds, or in the case of many tubular white flowers, by nocturnal feeders like bats or large moths.
Pima County has tried to curtail this problem by deterring homeowners from planting some of the worst offenders – such as Mulberry, fruiting olives and seeding Bermuda grass. Even so, there are hundreds of native plants that are all over the desert that one can hardly banish from existence.
If you are planting a new landscape you can certainly avoid filling your own personal space with highly allergenic plants. Here are some native plants that are best avoided:
• Grasses, such as deer grass, purple three-awn, big galeta, bush muhly and sideoats grama. Many other grasses, too – so ask before purchasing if you are quite allergic.
• Desert broom (only male plants are allergenic).
• Paloverde (all varieties) This is a plant that is so widespread you can’t go anywhere in Tucson where they are not blooming their hearts out. Perhaps limiting outdoor activity during their bloom time is a better solution.
• Needled evergreens – junipers, most all including our beautiful native alligator bark juniper; cypress, including Italian cypress and also our native Arizona cypress.
• Other trees – In general, the three other tree groups that are problematic are mesquites, oaks and pines. Again, mesquites are something one can hardly get away from, but at least it is good to know what the enemy is. One last tree that can make people sneeze unrelentingly is the African sumac (Rhus lancea).
So with all these plants that are allergy-causing, what can you plant in your yard?
The good news is that plants with showy flowers are rarely the culprit in one’s allergies. Bright showy flowers, with lots of color are using their beauty to attract the pollinators rather than counting on the wind to blow the pollen around, hoping to reach its target.
This means you are safe with all the desert cactus and succulents; all the beautiful vines that cover themselves with trumpet flowers; all annuals and perennials; shrubs – native or not – with tubular flowers, and so on. If you see bees or butterflies or hummingbirds attracted to a plant, you can be pretty sure it is not something that will get your allergies upset.
Fifty or 60 years ago, people came to the arid Southwest to help their respiratory ailments. The dry climate still is excellent for folks who are prone to those kinds of problems. It has been said that people “ruined” the air quality of the desert by planting all the non-native plants. While humans may have added to the pollen-bearing trees, it is evident that the desert was full of pollen long before any of us got here!
Cathy Bishop, co-owner of Mesquite Valley Growers Nursery, has more than 30 years of gardening experience. E-mail her at firstname.lastname@example.org.