Master Gardener: Landscaping with allergy-free plants

Since many people struggle with seasonal allergies, I paid a visit to the allergy-free garden located at Mill Creek Park in Visalia. What I expected to be boring, bland and bare of flowers was, to my surprise, beautiful, bountiful and offered some of my favorite blooms. I was excited and encouraged to see the options for landscaping with allergy-free plants, trees and shrubs.

Which plants are allergy free? To learn the answer to this question I began some research. Since the pollen produced by plants, trees and shrubs causes the unpleasant allergic reaction, it seems logical that plants low in pollen production are good choices for an allergy-free landscape. And that's true. But which plants are low in pollen production?

Plants achieve pollination in several ways. Some species of plants are pollinated by insects, birds and bees and some plants rely on wind pollination. Wind pollination is less reliable so plants that utilize this method of reproduction produce large quantities of pollen to ensure reproductive success. With such large amounts of pollen being produced, wind-pollinated plants are prime sources of allergens.

Wind-pollinated plants can be identified by their profusion of small inconspicuous flowers. Another key is to avoid trees and shrubs that are in bloom when the leaves are absent or are just beginning to grow. Also avoid plants that have a large number of catkins, or blooms that hang in dangling inflorescences. Wind-pollinated trees that cause the worst allergenic reactions in the greatest number of people are mulberry, olive, acacia, sycamore, almond, and walnut. Alder, birch, elm, maple, oak, poplar, sweetgum, and willow also cause allergies, but generally less of a reaction or in fewer people.

What can be planted in place of these? Some excellent suggestions can be found in The Birds and Bees Guide to Allergy Free Living by Scott E. Seargeant of Visalia. He offers several allergy free alternatives to the allergy producing plants. In place of the graceful willow, try the equally elegant mayten tree. Try a Golden Rain Tree instead of an Acacia. Plant vinca flowers (periwinkle) instead of the paludosum daisy, and plant a mugo pine instead of the allergy producing juniper shrub. And, as a final suggestion (there are so many more!), replace the stately sycamore tree with the beautiful blooms of the tulip tree.

Grasses and weeds also produce an abundant amount of allergy-inducing pollen. The best way to reduce their pollen is to minimize their presence in the landscape. Eliminate weeds from garden beds and keep up with the weekly mowing of the lawn, especially if it is common bermudagrass, the worst allergen. In the active growing season, bermudagrass sends up spikes of flowers that contain the dreaded pollen. Through regular mowing, these flowers are cut down, reducing the amount of pollen released into the air. Weeds that are particularly troublesome to allergy sufferers are pigweeds, johnsongrass, lambsquarters, plantain and certain members of the daisy family, like ragweed. Keep your landscape as weed-free as possible to aid in eliminating these pollen producers.

Contact allergies can also be irritating. It may require trial and error on each individual's part to determine those plants that are the cause of such allergies. Of course there are the standards that most people react to like poison oak, stinging nettles, and some grasses.

While I initially thought an allergy-free landscape would be boring and bloom-free, I have learned that it is possible to have a pleasant garden that is also healthier for allergy sufferers.

Seargeant's book actually lists some of my favorite plants as allergy-free options for the landscape. These include glossy abelia, azalea, bougainvillea, butterfly bush, Japanese camellia, forsythia, hydrangea, lantana, cape plumbago, western redbud tree, crape myrtle, jacaranda tree, saucer magnolia, coastal redwood, dichondra, periwinkle, peony, ranunculus, tulips and pansies, as well as many more.

So if you struggle with allergies, do some research, assess your landscape and see if there are some allergy-free options that you might also enjoy.

Jana Mercado is part of the Tulare-Kings Master Gardener Program. Call 582-3211, ext. 2736, e-mail cekingsdavis.edu or write UC Cooperative Extension Master Gardeners, 680 N. Campus Drive, Suite A, Hanford, CA 93230.

(April 18, 2007)