When I consult with my landscape design clients, I typically ask if any family members have allergies. Over the years, I’ve learned that landscaping with low-allergen plants can improve an allergy sufferer’s quality of life considerably.
For a reference guide, I’ve used Thomas Leo Ogren’s Allergy-Free Gardening: The Revolutionary New Guide to Healthy Landscaping. This week, Ten Speed Press released Ogren’s latest book, The Allergy-Fighting Garden, and I like it even better than his earlier book.
In The Allergy-Fighting Garden, Ogren again includes his Ogren Plant Allergy Scale (OPALS) for ranking various plants. He has updated the rankings since publishing Allergy-Free Gardening in 2000. He also devotes a chapter to eliminating mold spores, a major source of allergic reactions. Then there’s his chapter on allergy-blocking hedges.
Ogren rates plants on a scale of 1 to 10, with 1 being lowest in allergens, and 10 being highest. Using Ogren’s rankings, what low-allergen plants might you install in your Colorado garden?
For ground covers, you could use prairie winecups (Callirhoe involucrata), veronica, soapwort (Saponaria), orange carpet hummingbird (Zauschneria garrettii) and cranesbill geraniums, all of which I’ve grown successfully in my Denver garden. They rank from 1 to 3.
As for taller bulbs and perennials, try iris, allium, tall garden phlox, geum, Jupiter’s beard (Centranthus ruber), hummingbird mint (Agastache), sea lavender (Limonium), wild indigo (Baptisia australis), Butterfly weed (Asclepias tuberosa) and snapdragon (Antirrhinum majus).
Then of course, there are trees and shrubs to consider. They’re particularly important because the males (who are the pollen producers) generate significantly more allergens than smaller plants do. Good choices include hawthorns (Crataegus), barberry (Berberis), butterfly bushes (Buddleia), red chokeberry (Aronia arbutifolia), deciduous viburnums, serviceberries (Amelanchier), and some maples, such as Acer rubrum ‘Autumn Glory’, ‘October Glory’ and ‘Red Sunset.’
Avoid most grasses, especially Kentucky bluegrass, whose male cultivars carry a 9 rating. But be aware that the female cultivars (if you can find one) carry only a 1 rating. A good choice for turf grass is tall fescue, which Ogren ranks at 3.