Seasonal allergies affect many Michigan gardeners. Allergies can make your gardening chores miserable and often gardeners blame the plants they are tending for their problems. The good news is that most common Michigan garden plants are not the cause of nasal allergies. There are some plants, however, that you may want to avoid. In this article we are talking about plants that cause nasal allergies, not skin rashes or food allergies.
Natures rule is that plants that have showy flowers, the types we like to plant in our flower beds, have large grains of pollen that need insects or other animals to carry them from plant to plant. They are colorful or marked in various ways to attract those pollinating insects. The pollen from these plants seldom floats in the wind and therefore shouldn’t drift into your nostrils and cause distress. (If you stick your nose into them and suck up a whiff, you could have a reaction.)
The plants that do cause problems are those who have inconspicuous flowers. These plants rely on the wind to carry pollen from plant to plant and these are the plants that produce pollen your nostrils may intercept, provoking your immune system and causing seasonal allergies. Plants in the grass family, some trees and shrubs and a few common weeds are the biggest causes of allergies.
The earliest seasonal allergies are generally caused by trees. Trees often pollinate before they leaf out -or when the leaves are still small. In Michigan that can be as early as March. Willow, birch, aspen, oak, poplar, ash, hickories, walnuts, elm, sweet gum, sycamore, maple, cottonwood, ceanothuses, boxwood, cedar.
Some ornamental maples have been developed that have no pollen. The red maple ‘Autumn Glory’ is one. Any tree or shrub that is a female will not have pollen. Many trees and shrubs have separate male and female plants. The female plant is the one that fruits. Sometimes nurseries will label plants as male and female. Remember you won’t get fruit or seeds if you don’t also plant a male- and deal with pollen- somewhere nearby. But if fruit isn’t important look for female varieties of trees and shrubs if allergies bother you.
Pine pollen can cause allergies but as pollen goes it is very heavy and doesn’t drift far. Keep pine trees away from the house 100 feet or so and you probably won’t have a problem. Don’t stir up pine pollen that has fallen on cars or equipment either.
Trees and shrubs that don’t provoke allergies include those with showy flowers such as crabapples, cherries, horse chestnut, magnolias, black locust, redbud, catalpa, holly, lilacs, forsythia, dogwood, azalea, rhododendron, hydrangea, and viburnums. The female Ginko, (males are the sex most often sold) is also free of allergy causing pollen.
When we get to late spring and summer the most common allergy causing plants are grasses, a few weeds also begin to cause problems. Gardeners who have seasonal allergies may want to avoid ornamental grasses, some of which can cause allergies. Keep weedy grasses pulled out of flower beds before they go to seed. Timothy and orchard grass are two prime allergy causing grasses. These are often used for hay, which may be where the name hay fever, comes from.
In late summer and fall, before a hard freeze, the primary culprit for seasonal allergies is rag weed. Goldenrod, a beautiful showy flower is not the cause of allergies. Ragweed is a tall rangy plant with leaves similar to a marigolds, and greenish ball-like inconspicuous flowers.
Pigweeds, of which there are several types, began flowering in late June in Michigan and bloom on and off until a hard frost. They can cause allergy symptoms when pollinating. Pigweeds belong to the amaranth family. This diverse family has some edible seeded varieties and some ornamental varieties such as Love Lies Bleeding, which allergy prone gardeners may want to avoid. Lambsquarters, another common weed that blooms in late summer and fall can also cause allergy symptoms
Other than ornamental grasses and amaranths, most garden plants left in the garden do not cause any serious nasal allergy threat. However when some flowers are cut and brought indoors, the pollen dries out and has a greater tendency to cause nasal allergies, especially if allergy sensitive people are close to the cut flowers. Lilies, members of the daisy family and goldenrod are frequent culprits here.
Some people have allergic reactions to strong scents, which are different than a nasal allergy caused by pollen, but can also be quite annoying. If you have a reaction to strong scents you may want to avoid all highly scented flowers. Usually there are varieties of the plant which have a milder scent. Roses, daffodils and lilies are examples of plants that have highly scented and milder scented varieties.
After a hard frost most pollen shedding will stop. However another nasal allergen trigger may cause problems. Mold often causes allergies and moldy tree leaves can trigger nasal allergies. Plants that have heavy infestations of white fly, aphids or scale insects often develop sooty mold. Sooty mold grows on sweet secretions or excrement from insects eating plant sap. Houseplants often have these pests and then can indirectly cause nasal allergies.
While gardeners can avoid planting highly allergenic plants they usually can’t control what their neighbor’s plant and some pollen can drift a good distance. However practicing good gardening techniques like planting pollen free varieties, keeping the garden weeded and working to control insect pests will do a lot to help nasal allergy sufferers continue to garden. Consult with a doctor for medical controls for nasal allergies.