April 7, 2009

A Sensible Approach to Plant Pollen Allergies

I don't want to be an allergy fanatic, and you probably don't want to be one, either. But the American Academy of Asthma, Allergy and Immunology (hmm, I think they could use a shorter name, too) reports that more than 35 million Americans are affected by seasonal allergies, often known as hay fever, and that number is growing. Informed gardeners, landscape designers and others in the hort world have a great opportunity to reduce this problem through the advice we give to others and the plant choices we make for our own landscapes.
But information about allergy-causing plants can be difficult to find; I've certainly never seen a plant tag with allergy information on it. In lieu of carting around a reference book each time you visit a nursery, here are a few ideas to point you toward low-allergy plants.


Some trees - like this maple - produce huge amounts of pollen.

1. Focus on Trees. A large tree that merits a poor allergy rating (10 is the worst on the OPALS scale) will produce much more pollen than a perennial with the same rating. In addition, if you find that a perennial is aggravating your allergies, you can easily pull it out. You might not have the resources to do the same with a mature tree. Choosing to plant trees that cause little or no allergy will make the biggest impact on the pollen problem. If you spend only one hour studying plant allergies, spend it researching the trees you are considering for your landscape.

2. Be a Feminist. Turn your mind back to high school biology, when we learned that some plants have only female parts, some have male parts, and some have both. Plants with just female parts do not produce pollen to cause allergy, while their male counterparts produce large amounts. Male plants (especially trees) are popular choices because they do not produce messy fruits, but they often have horrible allergy ratings. Be cautious about planting 'fruitless' male trees or shrubs.


Showy flowers generally don't produce much pollen.

3. Double Your Delight. Here's some good news for flower-lovers: plants that produce small amounts of sticky pollen must attract insect or bird pollinators with their brightly colored, showy flowers. That means the plants with the most beautiful flowers often cause little allergy. When some of the pollen-producing anthers have morphed into extra petals, producing a 'double' flower, the flower produces even less pollen.

4. Be Spooked by Ghostly Flowers. The flowers of wind-pollinated plants are usually small and pale green or white (hence the ghost reference). They're often so inconspicuous that you may not even realize the plant has flowers. These plants produce large amounts of lightweight, dry pollen that is carried long distances by the wind until it alights on a moist surface like a plant stigma or a human's nasal membranes.


Trumpet-shaped flowers like Vinca are good low-allergy choices.

5. Turn to Trumpets. Flowers that are shaped like trumpets generally hold their pollen inside where it won't make you sneeze. Choosing plants with trumpet-shaped flowers will be good for your nose, and bees and hummingbirds will applaud your choice as well.

Sorting out low-allergy plants from high-allergy plants is not a simple task, but hopefully these five suggestions will be a helpful way for you to make plant selections that have a positive impact on the pollen allergy problem.

10 comments:

  1. A very helpful post indeed. Those trees sure do get us here. I think the pines and cedars mostly, but for sure all of them contribute to so much pollen in the air. It is good news that the showiest flowers produce the smallest amount of pollen!

    I see spring has caught you guys. I think I saw this post before, not sure why I didn't comment-sorry! Also, I had thought I had your blog on my sidebar all this time and am shocked to see I did not. I am a bad ole blogger lately! I am sorry. I try very hard but sometimes some blogs get past me. I have added it now. Sorry if it caused you any confusion. Happy gardening. I do hope all the snow has melted and you got your roses planted.

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  2. VW, Thanks for the great information...Once upon a time, I was never plagued with allergies, but now that's not true! It's the cedars that get to me! Have a good week! gail

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  3. I have asthma and emphysema and bronchitis and my lung collapsed twice. Getting my breath in the winter is a real problem. Getting my breath in the spring and summer is a lot easier than winter for me. I don't know what this season will be like but I hope I don't have to wear a mask.

    Gobsmacks

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  4. First of all, how did I miss this post? Was it really from last week?
    Anyway, this was very interesting and I had no idea about the female flowers having less pollen. I learned a lot!
    I've noticed my allergies starting up this past week, I think it's the cedar around us, next is the cottonwood.

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  5. "Bad ole blogger" indeed! Tina's the one who brought me to your site, and I'm sure glad she did. Thanks for the great information about allergy-problem plants and their counterparts. You know, I'm wondering if the increase in allergic reactions isn't initiated by poor indoor air quality? A scientist friend of ours speculates that people become sensitized by indoor allergens (pet dander, mold spores, dust mites, etc.), and then overloaded immune systems fighting those allergens just can't cope with the outdoor offenders.

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  6. Hi VW, what a public service post! If only we had known about the maple trees before the city planted them on every street in town. The pines are not much better. After the maples, then the pines give us a yellow dust that especially shows up on the macro photos of dark petaled plants. Nice to know about the trumpets and doubles too. Thanks!
    Frances

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  7. A very informative post.

    Next time I reach for an anti-histamine I'll think why rather than just hay fever.

    I only have to touch some conifers and I get a rash.

    Cheers
    Rob

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  8. Frances, perhaps I should have included some info about evergreens. But it's hard to tell where to stop when trying to create a simple plan to deal with a complex problem! Pine, fir and spruce pollens have a waxy coating that makes them less irritating to nasal membranes. So even though they produce vast amounts of pollen, it doesn't cause much allergy. Juniper and cypress, in contrast, cause massive amounts of allergy. Figuring out which plants are bad for allergies isn't always intuitive!
    And there are some female maple cultivars - like Autumn Fantasy, Indian Summer, Autumn Glory, and October Glory - that produce no pollen. You just have to find them.

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  9. I had hayfever for many years, until I started taking Red Clover blossoms all year round. For the last 2 years I've been charging around up to the neck in high pollen in June and July and totally enjoying it!

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  10. Hi VW, an important topic that needs more publicity. Maybe we should petition our nurseries to demand allergy information be included on the label. There is now info re weeds which is a result of increased public consciousness, so why not allergy info?

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