A Dozen Tips For Producing Low Allergy Gardens
By Thomas Ogren, Fri Dec 9th

A Dozen Tips for Producing Low-Allergy Gardens

Ó Thomas Leo Ogren

What we plant often has a direct effect on our own health andthe health of those near us. A pollen-producing male tree in ourown yard will easily expose us to ten times more pollen thanwould a similar tree growing just down the block. This can becompared to second-hand smoke. It is possible to inhale somesmoke from a person smoking a block or two away from you, but itis hardly the same as someone smoking right next to you. It isthe same with plants. If your own yard is full of allergenicplants, then you will be exposed most. Elementary schoollandscapes are frequently highly allergenic because all toooften they have been landscaped with trees and shrubs that willnot produce any seeds, seedpods or fruit—which the childrenmight want to toss at each other. What is over-looked is thatthese tidy choices are usually male cultivars (clones) andalthough they are “litter-free,” they are prodigious producersof allergenic pollen. I am now involved with a pollen-freelandscape planting at a new elementary school in Tulare County,California. This work is being sponsored by their local asthmacoalition and it is very encouraging to see preventativemeasures like this being taken. Children suffer greatly fromallergies and asthma, and asthma is now the most common chronicchildhood disease in the US. Another fine example of low-pollenlandscaping surrounds the new American Lung Association RegionalHeadquarters in Richmond, Virginia. With “green” constructionprinciples a new ‘Breathe Easy’ allergy-free office wasconstructed. The allergy-friendly landscape plant materials arepredominantly female, and compliment the clean air building.Other Breathe EasyÔ offices are also now using pollen freelandscapes, as are numerous Heath Houses. Twelve tips: Remember,the greater the exposure to pollen, the greater the incidence ofpollen-triggered and asthma.

1.Don’t plant any male trees or shrubs. These are often sold as"seedless" or "fruitless" varieties but they’re males and theyall produce large amounts of allergenic pollen. 2.Do plantfemale trees and shrubs. Even though these may be messier thanmales, they produce no pollen, and they actually trap and removepollen from the air. There is also some very good all-female sodto use for pollen-free lawns. As an added bonus, these femalelawns stay low and require less frequent mowing. 3.Plantdisease-resistant varieties: mildew, rust, black spot and otherplant diseases all reproduce by spores and these spores causeallergies. Disease resistant plants won’t get infected as muchand the air around them will be healthier. 4.Use only trees andshrubs well adapted for your own climate zone. Plants grown inthe wrong zone will often fail to thrive. Because they are nothealthy, they will be magnets for insects. Insect residue,"honeydew," is a prime host for molds and molds produceallergenic mold spores. Often native plants will be thehealthiest choices. 5.Be careful with the use of allinsecticides, fungicides, and herbicides. Accidental exposure toall of these chemical pesticides has been shown to causebreakdowns in the immune system. Sometimes one single heavyexposure to a pesticide will

result in sudden hypersensitivityto pollen, spores, and to other allergens. This is as true forpets as it is for their owners. Go organic as much as possible.Make and use compost! 6.Diversity is good. Don’t plant too muchof the same thing in your landscapes. Use a wide selection ofplants. Lack of diversity often causes over-exposure. Use lotsof variety in your gardens. 7.Wild birds are a big plus becausethey eat so many insects. Plant fruiting trees and shrubs toencourage more birds. Suet also attracts many insect-eatingbirds. Insect dander causes allergies and birds consume anincredible amount of aphids, whiteflies, scale, and otherinvertebrate pests. 8.Use pollen-free selections wheneverpossible. There are many hybrids with highly doubled flowers andin many cases these flowers lack any male, pollen parts. Formaldouble chrysanthemums, for example, usually have no pollen.Another example would be almost all of the erect tuberousbegonias. These have complete female flowers, but their maleflowers have nothing but petals, making them pollen-free. 9.Ifyou simply must have some high-allergy potential plants in youryard, just because you love them, then watch where you plantthem. Don’t use any high-allergy plants near bedroom windows ornext to patios, well-used walkways, or by front or back doors.Place the highest plants as far away from the house aspossible and downwind of the house too. Remember: the closer youare to the high-allergy tree or shrub, the greater is yourexposure. 10.Know the exact cultivar name of a tree or shrubbefore you buy it. Don’t buy any that are not clearly taggedwith the correct cultivar (variety) name and the Latin,scientific name. Compare the exact name of the plant with itsOPALS/TM ranking. With this scale, 1 is leastallergenic, and 10 is the most allergenic. Try to achieve alandscape that averages at OPALS #5, or below. 11.If you have atree or hedge that has high potential and don’t want toremove it, consider keeping it heavily sheared so that it willflower less. Boxwood, for example, has allergenic flowers but ifpruned hard each year, it will rarely bloom at all. 12.Getinvolved with your own city’s tree and parks departments, andencourage them to stop planting any more wind-pollinated trees.There are thousands of fine choices of street trees that do notcause any allergies and we should be using these instead.Working together we can make a healthy difference, and we’ll allbreathe better for our efforts.

*Note, with the dioecious plants (separate-sexed) males causepollen-allergy, and females because they are pollen free, donot. Examples of some of these dioecious plants are: red maple,silver maple, box elder, holly, willow, aspen, cottonwood,poplar, fringe tree, pepper tree, carob tree, Osage orange,mulberry, cedar, juniper, podocarpus, yews, ash, date palms, andeven asparagus.

About the author:Thomas Ogren is the author of Allergy-Free Gardening, Ten SpeedPress. Tom does consulting work on landscape plants andallergies for the USDA, county asthma coalitions, and theCanadian and American Lung Associations. He has appeared on HGTVand The Discovery Channel. His book, Safe Sex in the Garden, waspublished in 2003. In 2004 Time Warner Books published: What theExperts May NOT Tell You About: Growing the Perfect Lawn. Hiswebsite: www.allergyfree-gardening.com