Pecan and hickory pollen allergy
Carya
Pecan and hickory trees release wind-borne pollen in spring that can cause hay fever. AAFA rates both as very allergenic.
What it is
Pecan and the hickories are trees in the genus Carya, and pecan is itself a hickory, one of the better-known of the group called pecan hickories.1 Pecan grows mainly in the lower Mississippi Valley. It reaches west to eastern Kansas and central Texas and east to western Mississippi and western Tennessee, with scattered trees from southwestern Ohio to Kentucky and Alabama. It also grows locally in northeastern and central Mexico.1 Improved pecan varieties are grown widely in the US for their nuts.1
Each pecan tree carries both male and female flowers, in separate catkins. The male catkins are slender and 3 to 6 inches long, and the pollen they release is carried by the wind.1 Hickory pollen is microscopic, unlike the large pine pollen shed at the same time of year in North Carolina.7
Symptoms it causes
Pecan pollen is an important cause of allergic respiratory disease.2 AAFA lists both pecan and hickory among the trees that cause the most allergy symptoms in the US and describes both as very allergenic.3 A 1999 University of Georgia article named oaks, walnuts and hickories as the trees people have the most trouble with, because their small pollens cause hay fever.8
The pollen is breathed in. Tree pollen allergy can bring a runny or stuffy nose, sneezing, itchy nose, eyes, ears and mouth, red and watery eyes, and swelling around the eyes. People with allergic asthma may also have asthma symptoms while the trees are releasing pollen.4
Pecans are also tree nuts, and tree nut allergy is one of the most common food allergies.5 Tree nuts are among the foods most often linked to anaphylaxis, a severe reaction that can affect the whole body.6
Where and when it grows
Pecan flowers from April through May. Heavy rain while the trees are flowering can prevent pollination.1
Hickories in North Carolina release pollen in March and April, at the same time as pines and oaks.7 In Yavapai County, Arizona, the University of Arizona Cooperative Extension lists the pecan pollen season as February to April.9
Hickory is found in the Midwest, Northeast and Southeast. Pecan grows in those regions as well, and also in California and Arizona.3
Symptoms it can cause
When to get help
See an allergist if
- Allergy symptoms last for several months of the year
- Allergies bring repeated sinus problems, a blocked nose or trouble breathing
- Over-the-counter remedies don’t control your symptoms
- Allergies or asthma get in the way of daily life
- You often wheeze, cough at night or after exercise, or feel short of breath
Based on ACAAI’s “When To See an Allergist”. General information, not medical advice.
Questions
Are pecans tree nuts?
Yes. AAAAI lists pecans among the tree nuts, and it describes tree nut allergy as one of the nine most common food allergies.5
Is pecan a kind of hickory?
Yes. Pecan belongs to the hickory genus, Carya, and is one of the better-known of the pecan hickories.1
When do pecan trees release pollen?
Pecan flowers from April through May. The pollen comes from slender male catkins and is carried by the wind.1
Where do pecan and hickory trees grow?
Hickory is found in the Midwest, Northeast and Southeast. Pecan grows in those regions too, as well as in California and Arizona.3
Sources
- Carya illinoensis (Wangenh.) K. Koch. USDA Forest Service, Silvics of North America. Read on October 15, 2026.
- Immunoproteomic identification of allergenic proteins in pecan (Carya illinoinensis) pollen. Journal of Proteomics. Read on October 15, 2026.
- Tree Pollen Allergy. Asthma and Allergy Foundation of America. Read on October 15, 2026.
- Tree Pollen: Spring’s First Allergy Offender. Asthma and Allergy Foundation of America. Read on October 15, 2026.
- Everything You Need to Know About Tree Nut Allergy. American Academy of Allergy, Asthma & Immunology. Read on October 15, 2026.
- Tree Nut. American College of Allergy, Asthma and Immunology. Read on October 15, 2026.
- Pine Tree Pollen Unlikely to Cause Spring Allergies. North Carolina State University, College of Natural Resources. Read on October 15, 2026.
- Don’t Blame Pine Trees for Springtime Sneezes. University of Georgia College of Agricultural and Environmental Sciences. Read on October 15, 2026.
- Bulletin #2 Plants That May Cause Allergies in Yavapai County. University of Arizona Cooperative Extension, Yavapai County. Read on October 15, 2026.