Cottonwood (Tree)
Description
Cottonwood trees (Populus species, section Aigeiros) are fast-growing, large deciduous trees belonging to the willow family (Salicaceae). They feature broad canopies and triangular or heart-shaped leaves that flutter in the breeze. Cottonwoods are best known for the fluffy white seeds resembling cotton that fill the air in late spring and early summer. While visually dramatic, it is the pollen released earlier in spring, not the cotton-like seeds, that primarily triggers allergies. Common species include eastern cottonwood (Populus deltoides) and black cottonwood (Populus trichocarpa).
Allergy Symptoms
Cottonwood pollen commonly causes:
- Sneezing and runny or congested nose
- Itchy, watery, and red eyes
- Coughing and throat irritation
- Wheezing and exacerbation of asthma symptoms
Cottonwood belongs to the poplar family and shares allergenic proteins with related trees such as willow and aspen. Individuals allergic to cottonwood may also react to these related pollens. Some people with cottonwood allergies may experience Oral Allergy Syndrome (OAS), with potential cross-reactive foods including apples and sunflower seeds, though this is less common than with birch pollen allergies.
Typical Pollination Period
Cottonwood trees typically pollinate in early to mid-spring, from late February through April, with earlier pollination in warmer southern regions. The release of fluffy seeds in late spring or early summer is often mistakenly blamed for allergy symptoms, but these seeds contain little allergenic material. The pollen released weeks earlier is what triggers allergic reactions.
Geographic Distribution
Cottonwood trees are widespread across the Northern Hemisphere:
- North America: Particularly abundant in central and western regions, especially near rivers, streams, and floodplains
- Europe: Widely cultivated and naturally occurring across temperate regions
- Asia: Common in temperate areas, especially northern China and parts of Siberia
Tips for Reducing Exposure and Managing Allergies
- Monitor local pollen forecasts and limit outdoor activities during high pollen days
- Keep windows closed and use air purifiers with HEPA filters indoors
- Shower and change clothes after spending time outdoors
- Use antihistamines or nasal corticosteroids as recommended by a healthcare professional
- Remember that the cotton-like seeds are not the main allergen; pollen peaks earlier in spring
- Consider allergy testing and immunotherapy for persistent or severe symptoms