Documents: Special Interest: Horticultural Therapy:

Safe Sex in the Garden
by Thomas Ogren
by Thomas Ogren


Thomas Leo Ogren is the author of Allergy-Free Gardening. His most recent book, Safe Sex in the Garden, was published March 2003, by Ten Speed Press. Two of his previous books, both novels, were published by New Readers Press, and are used nationwide in adult literacy programs.

Tom does consulting work for the USDA, the American Lung Association, for, and recently for county asthma coalitions. He is considered to be the leading authority on pollen-producing male cultivars, and on their opposites: pollen-free female plants. He is currently working on a book about lawns, for AOL Time Warner Books.

Tom and his wife, Yvonne, have four children. They live in San Luis Obispo, California.

June 27, 2004

More than 35 million Americans suffer from seasonal allergies, according to the American Academy of Allergy, Asthma and Immunology. Part of the problem, says horticulturist Thomas Leo Ogren, is rooted in the types of plants commonly used in landscaping.

For about 50 years, commercial and residential landscapers have been planting single-sex male trees and shrubs almost exclusively. Males don't litter the ground with seeds, fruits or pods but they do emit high quantities of pollen into the air and up our noses. The solution, Ogren suggest, may lie in a form of gardening girl power. In his new book, Safe Sex in the Garden, Ogren argues that boosting the use of female plants, which absorb pollen in the air, could help dramatically reduce the suffering of those affected by pollen allergies.

Creating an allergy-safe garden doesn't have to mean a male-free one, Ogren adds. Where you place male plants makes a big difference. Male plants placed next to the door of a house are likely to bring a great deal more pollen into your home than those located at the far-end of a garden, he says.

Gardeners can also turn to formal doubles, which are plants with petals that open continuously from the center and do not have stamens, or male parts. Many camellias, chrysanthemums and begonias fall into this category, Ogren says.

Ogren's book is full of recommendations for allergy-free gardening. For those gardeners who want to play it completely safe, Ogren recommends sticking with the female cultivars of plants. Some of his suggestions for trees, shrubs and ground covers are listed below:

  • Box Elders
  • Red Maple trees
  • Silver Maple trees
  • Cedar trees (females produce fat, rounded cones about four inches tall)
  • Juniper trees and shrubs (fruit-bearing trees are female)
  • Holly trees and shrubs (hollies bearing red berries are female)
  • All fruit-bearing Mulberry trees
  • Fruit-bearing Yews of the Taxus and Podocarpus species
  • Red Apple Iceplant (a low-allergy ground cover)
  • Manzanita (a low-allergy ground cover)
  • Buffalo Grass (an allergy-free ground cover; Ogren recommends a female cultivar, blue-green in color, called Legacy.)

Please visit Toms site at


  • New Eden
  • Kids Garden
  • Plant a Row Grow a Row