I'm interested in knowing which plants cause allergies because I experience allergies to pollen from grass and several trees. Did you know that repeated exposure to large amounts of allergenic pollen can cause you to develop an allergy to it, even if you don't have one now? Both those people who already have allergies and those who could develop allergies (that pretty much covers everyone!) might be interested in the following list. For information on allergy free gardening guidelines, see my article A Sensible Approach to Plant Pollen Allergies.
I went through Thomas Ogren's "Allergy-Free Gardening" book and picked out some of the plants with a rating of 9 or 10 on the OPALS scale. These are the plants that cause the most allergies. The entire list is huge, so I'm just including plants that are common to temperate climates like mine, plus a few that I remember from my Californian neighborhood. If you live in a mild climate, you'll just have to buy the book to find the worst allergy offenders for your area - including many types of allergenic palms and grasses. Actually, I recommend this book for every gardener and designer.
The plants are listed alphabetically by latin name with common names in parenthesis. In many cases just the male forms are the offenders, as females don't produce pollen to cause allergies. Sorry I didn't do the italics thing but I just didn't have the patience for it on this long list.
Acacia (wattle, mimosa, whitethorn)
Acer negundo 'Aureo marginatum', 'Baron', 'Violaceum' (male box elder)
Acer rubrum 'Autumn Spire', 'Tiliford' (male red maples)
Acer saccharinum (male silver maple)
Agrostis (bent grass, redtop)
Ailanthus (stink tree, tree of heaven)
Alnus (alder)
Ambrosia (ragweed)
Anaphalis (pearly everlasting)
Artemesia (dusty miller, sagebrush, tarragon, wormwood)
Aruncus sylvester
Broussonetia papyrifera (male paper mulberry)
Callistemon (bottlebrush)
Carex (sedge)
Carya (hickory, pecan)
Chionanthus (male fringe tree)
Corema (broom, crowberry, poverty grass)
Cryptomeria japonica (Japanese cedar)
Cupressus (cypress)
Cynodon dactylon (Bermuda grass)
Elaeagnus angustafolia (Russian olive)
Elaeagnus pungens (evergreen silverberry)
Fescue glauca (blue fescue)
Fraxinus (male ash tree)
Gymnocladus dioica (Kentucky coffee tree)
Helenium autumnale (flowering sneezeweed)
Juglans (walnut, butternut)
Juniperus (male juniper, cedar, habbel)
Laurus nobilis (male bay, sweet bay, sweet laurel)
Lycopodium (club moss, ground cedar, princess pine)
Mangifera indica (mango)
Morus (male mulberry)
Olea europaea (olive)
Pennisetum setaceum (fountain grass)
Phalaris (canary reed grass)
Phleum (timothy grass)
Platanus (sycamore, plane tree, buttonball tree)
Poa (Kentucky bluegrass) *if mowed often it won't produce pollen
Podocarpus (male fern pine, yew pine)
Populus (male aspen, cottonwood, poplar)
Quercus (evergreen oak, ie coastal live oak)
Rhamnus (buckthorn, coffeeberry)
Rhus (sumac, poison ivy, poison oak)
Salix (male willow)
Schinus (male pepper tree)
Senecio (cineraria, natal ivy, german ivy, wax vine)
Thalictrum (meadow rue, buttercup)
Zelkova (Japanese zelkova)
After perusing the list, do you notice any plants that have given you allergy symptoms? Are there any that you might need to remove from your landscape? When we lived in California, I often walked past a long row of olive trees on my morning walks. By the end of the row, I usually had a headache, but didn't attribute the problem to the olive pollen until I reread Ogren's book and saw that olives are rated as a 10. I turn to his reference book as I'm considering new plants - especially trees - for my landscape. I'm willing to take medicine and put up with the sniffles in order to continue to enjoy time outdoors, but of course I'd like to reduce the problem by reducing pollen levels in my yard and community.
ALLERGY FREE GARDENING
helping people plant right, water less and garden more
Reprinted with permission from VW Garden Blog
VW is a gardener who was totally spoiled by three years spent living in mild California and now has a bad attitude about the snow that falls for 6 months each year on her Spokane, Washington garden. Below are some of her favorite books, on subjects ranging from sustainable gardening practices to books that inspire to ones that are just plain fun. (or as VW puts it, does it make you a big nerd if you are fascinated by a book about worms?)
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