If you are one of the millions of people with allergies or asthma, The Allergy-Fighting Garden (Ten Speep Press, 2015), by Thomas Leo Ogren, is for you. This book shows you how to avoid plants that trigger allergies and how to create a garden that will actually protect you by trapping pollen and cleaning the air around you. Ogren’s revolutionary approach combines the best of his previous books into a full-color guide, including hundreds of new and updated plant listings and photographs. This excerpt, which focuses on creating a low-pollen landscape, is from Chapter 2, “How to Fight Allergies Close to Home.”
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How to Fight Allergies Close to Home
You may wonder whether what you plant in your own yard can make any difference, because pollen can blow in from hundreds of miles away. But what you plant in your own yard most likely will make all the difference in the world. With pollen allergies, everything is in the actual dose received. If you have a headache and take two aspirin it will be just fine, but if you take twenty or thirty aspirin it will be terrible. It is the same thing with exposure to allergenic pollen; a small amount of pollen might well actually even be good for you, it would probably stimulate your immune system. But a very large overdose of pollen will quickly make many people ill. The closer you are to the source of the pollen, the greater your exposure will be.
A large pollinating tree will shed most of its pollen right next to the tree itself. The largest amount of this pollen will be found within a few dozen feet (or less) of the drip line of the tree. If the tree makes allergenic pollen, then those who live closest to this tree will get the biggest dose, the overdose. Yes, some of this pollen may drift on down the block, but exposure next to the tree may easily be well more than a hundred times greater than it would be a few houses away. Allergy researchers call this phenomena “proximity pollinosis.”
You can understand proximity pollinosis by imagining cigar smoke. If someone is a block away from you, smoking a cigar, you might get exposed to a very small amount of secondhand smoke. However, your exposure would be so slight that you might not even notice. The opposite would be the case if you got onto an elevator and someone inside lit up that same fat, smelly cigar. Ah, now indeed you’d be exposed to it. This is locality, and this is the exact same principle that is at work with proximity pollinosis.
Everyone Has a “Bucket”
It is well understood by many allergists that if someone is allergic to, say, six things, and three of them are removed, then the sufferer will often become symptom-free. This is an important insight. By creating an allergy-free yard, you will have eliminated the closest, most intense sources of what ails you. Even though your body will contact some allergens from outside your own area of control, your symptoms will probably diminish and sometimes they’ll disappear. This leads us to the bucket theory of allergy.
When you get up in the morning and feel great, you have an “empty bucket.” Then perhaps you absentmindedly run your hand over the top of the TV, kicking up a small dose of quickly inhaled dust. The dust goes “in your empty bucket.”
At breakfast you may eat something you’re allergic to and that, too, goes in your bucket. At this point you probably feel perfectly fine. You then inhale a dose of pollen from the bouquet of daisies on the table. This goes in your bucket, too. But there is still room in your bucket for a few more allergens and you still feel great. Your cat walks by and you inhale some cat dander. It goes in your quickly filling bucket, but still, you’re all right.
Now you go outside to get the newspaper and a little puff of wind knocks a small cloud of invisible pollen from the seedless male tree overhead. You inhale this pollen-filled air, and those thousands of microscopic allergens go in your now almost-brimful bucket, all of a sudden overflowing it. Now you suddenly feel miserable.
It is usually the cumulative effect of multiple allergens that makes us feel lousy. The trick is to eliminate and avoid as many likely allergens as possible, to not let our buckets overflow. We need not eliminate all the allergens in our environments, just as many of them as we can. As with so many things, allergy is usually a question of degree. In the above case, with some safer trees in the garden, you might well have remained symptom-free.
Being symptom-free, by the way, should be the goal of all of those who have allergies or asthma; there is no real “cure” for these diseases. The best medicine for allergy is avoidance; avoid whatever triggers the allergy. With the right amount of avoidance, you’ll remain symptom-free. As allergist David Stadtner, MD, has stated, “I have had many patients whose allergy symptoms improved by removing an offending tree or shrub near their home.” Sometimes removing just one tree or large shrub can make a huge difference.
Finding the Best Plants for Your Low-Pollen Landscape
It is entirely possible to design a very good, low-pollen landscape by using this information to select the best plants from those available at many quality nurseries and home garden centers. If you are buying plants at a nursery, especially trees or shrubs, don’t buy them unless they are properly tagged. The tag should have the complete Latin name of the plant, with genus and species, and the plant’s common name. For example, with the red maple tree commonly called “October Glory,” the correct tag would read, in this precise order: Acer rubrum ‘October Glory’. It also might be listed accurately but a tad differently, such as Acer rubrum c (or cv, or CV) ‘October Glory’. The c or CV simply stands for “cultivar,” which is the horticultural version of a cloned plant. You should always have in your hands a copy of The Allergy-Fighting Garden, so that you can compare the exact name of the plant in the nursery with the exact same plant in the book. If the plant is not named and ranked in the book, it’s safest not to buy it. When looking over a tree or shrub in a container at a nursery, you’ll have to compare the genus, the species, and the common name with what is listed in the book.
For years now I’ve been approaching large wholesale growers to see whether I could talk some of them into growing a collection of pollen-free plants or adopting OPALS tags on the plants they sell. This would make it very simple for shoppers to select the safest plants for them and their families. Unfortunately, to date there have been very few takers. One of the rare exceptions, so far, is the wholesale/retail grower and nursery Queux Patio Plants, on Guernsey, one of the Channel Islands. They are actively growing a large number of female plants. The owner of this nursery, Nigel Clarke, is totally committed to offering his customers the safest, healthiest, most allergy-free plants possible. His own nonprofit group, Green Legacy Guernsey, is committed to re-greening Guernsey, and doing so in a way that will not trigger allergies or asthma.
There are already a number of places (some online) selling what they’re calling “allergy-free plants,” plants that are anything but. These should be approached with extreme caution. I have registered trademarks on both “allergy free gardening,” and also on OPALS. No one is legally able to use these tags without permission, and I will not let people use the tags unless I am 100 percent convinced that the plants they’re selling are exactly what they should be. If I can get more nurseries to agree to grow and sell pollen-free female plants, they will be listed on the SAFE Gardening website.
Top-Grafting Sex Changes
If you are landscaping your yard from scratch and you follow this advice in on selecting low-allergy plants, you should be in good shape. But if you have an existing landscape, you will need to evaluate it to decide which plants can stay and which should be removed. In some cases, existing male trees can be top-grafted with scion wood from a female tree of the same species. This will affect a sex change. Some years ago I was talking to a midwestern city arborist about how his city had such an incredible number of male-cloned street trees. Most of these were recently planted, highly allergenic, male Chinese pistache trees. I told him that because these were fairly young trees, and because they were all deciduous, it would be a good idea to top-graft (or bud) them all over to female. He could do this in the winter when they were dormant. “You should give them all a sex change,” I said. The arborist shook his head and looked dismayed. “That is so California,” he said. Perhaps it was, but I’d much rather graft a male tree to female than chop it down. I’ve top-grafted quite a few fruitless male mulberry trees. Every mulberry I grafted took. In one season those highly allergenic male trees were converted into allergy-free female trees.
The Birds and the Bees, and the Butterflies, Too
Male trees produce no fruit for birds and small animals to eat, and they usually produce little or no nectar for butterflies, humming- birds, and honeybees. The past three decades of sterile, litter-free landscapes have dramati- cally reduced urban food sources for many of nature’s small creatures. As the sale of wind-pollinated, male cloned street trees expanded, it was accompanied by the decline in numbers of the cities’ butterflies and honey- bees. Deprived of major early-season food sources, many of these species simply starved. Allergy-free gardens and landscapes, with their reliance on female and insect-pollinated plants, may indeed be a bit messier. They will also bring us less allergy, less asthma, cleaner air, and more birds, honeybees, and butterflies.
Reprinted with permission from The Allergy-Fighting Garden by Thomas Leo Ogren, copyright (c) 2015. Published by Ten Speed Press, a division of Penguin Random House, Inc.