by Ken Lain, the mountain gardener
Allergy sufferers know the symptoms: Runny nose, Coughing and sneezing, Nasal congestion, Itchy nose, eyes, and throat. Autumn Ragweed gets most of the attention in the fall, but landscape trees are even be a bigger culprit. There is not much you can do about your neighbors’ trees or the city park. You can definitely plant allergy-free trees in your own yard. Here is our Top 10 List of Hypoallergenic trees planted for years of allergy-free enjoyment.
The presence or non-presence of pollen in a tree is a matter of the tree’s sexual reproduction method. This process involves flowers and pollen. Typically trees produce seeds only when the pollen from male flowers reaches female flowers, a process is known as pollination. This can happen through the action of bees and other insects that transfer the pollen from flower to flower as they feed on nectar, or the pollen drifts from flower to flower on air currents. The most infamous of these are male juniper trees.
A tree’s flowers can be either male or female, and only the male flowers produce pollen. Some trees are monoecious, meaning that individual trees produce both male and female flowers. Other trees are dioecious, meaning a particular tree has either male or female flowers, but never both.
Thus, with a dioecious tree, it is possible to plant a female tree that produces no pollen since the flowers are all female. Examples of allergy-free trees without pollen and mess are:
- Ash, Fraxinus
- Aspen, Populus tremuloides, also cottonwood
- Boxelder, Acer negundo
- Deodar Cedar, Cedrus
- Juniper, Juniperus virginiana
- Maidenhair, Ginkgo biloba
- Maples, Acer rubrum
- Mulberry, Morus
- Yew, Taxus
We only carry female trees at Watters Garden Center, making your choice easy. With other species, though, you may need to specify that you want a female tree that produces no pollen.
More Allergy Free Varieties
Many monoecious trees that produce pollen are suitable for allergy sufferers since their pollen is heavy, coarse, and improbable to drift on the wind and cause allergy symptoms. After all, the pollen of monoecious trees must be transported only a short distance to a female flower on the same tree, a task easily accomplished by insect pollination. Examples of monoecious plants with coarser pollen include:
- Crabapple, Malus
- Dogwood, Cornus
- Fir, Abies
- Flowering cherries and plums, Prunus
- Magnolia, Magnolia
- Ornamental pear, Pyrus calleryana
- Redbud, Cerci
- Spruce, Picea
For allergy sufferers, planting either female monoecious tree species or a dioecious tree species known to have heavy, coarse pollen reduces hay fever symptoms. Combine this tree list with hypoallergenic shrubs and flowers, with diligent weed control for allergy-free days in the garden. Sunsets will be brighter, butterflies more abundant, and the radio will only play your favorite songs with fewer allergy medications.
Until next week, I’ll be helping gardeners choose allergy free trees for a happier, healthier landscape