When it comes to trees, the real allergy troublemakers are hardwood deciduous trees – oak, elm, birch, maple, ash, alder, and hazel.

These trees generally pollinate from February to April or May. In the South, these trees begin pollinating as early as January; in the North, they begin in April.

People show cross-reactivity to trees in the beech, birch, alder and oak family, and in the juniper and cedar family. This means that if you're allergic to one type of tree, you're likely allergic to others in the same family.

If you're looking to plant trees on your property, look for species that do not aggravate allergies, such as catalpa, crepe myrtle, dogwood, fig, fir, palm, pear, plum, redbud and redwood trees.