Some tree species that bear separate male and female flowers on the same plant are called "monecious." Examples include honey locust, oak, sweetgum, pine, spruce, and birch. You can't do much but deal with these as a species.
"Dioecious" tree species bear male and female flowers on separate plants. Dioecious trees include ash, boxelder, cedar, cottonwood, juniper, mulberry, and yew. If you select a male plant you will have problems.
From an allergy perspective, the worst trees you can live around are dioecious males, which will bear only pollen and no fruit or seed. The best plants in your environment are dioecious females as they bear no pollen and are allergen-free.
Trees to avoid are male ash, pine, oak, sycamore, elm, male boxelder, alder, birch, male maples and hickory.
Things you can do to avoid a problem:
* Plan your landscape- Minimize exposure to known allergens by not planting and eliminating certain allergy-causing trees from your property.
* Plan your time outside- In order to minimize exposure, plan outdoor activities to coincide with times when the pollen count is lowest.
* Keep up with the pollen count- Follow the local pollen index (the number of grains per cubic meter of air) that will alert you to days when your particular allergens are most prominent.
* Allergy skin testing- Using the scratch or blood test for allergies can help you determine what type of pollen allergies you have.
Trees to Avoid - The Major Allergy Trees
Trees You Can Live With - Allergy Friendly Trees
