The pollens

Main allergenic pollens

All pollens do not provoke allergies. To cause allergy symptoms, it is essential that the pollen grains arrive to the respiratory mucosa of human being. Only plants anemophilous disseminate pollen grains by the wind, while entomophilous plants require the intervention of an insect to ensure fertilization by transferring pollen from the male to female flower receiver.
The pollens of high allergenicity are produced by anemophilous plants (trees and grasses).
To be allergenic, pollen grain must contain substances (proteins or glycoproteins) immunologically recognized as harmful to an individual.

The allergy potency of a plant species is the ability of its pollen to provoke an allergy for a part of the population.
Allergy potency can be:
- weak or null (species which can be planted in urban areas)
- Moderate (only a few trees or herbaceous of these species can be planted in urban areas)
- Strong (species which can not be planted in urban areas)

Comparative table of the different plants according to there allergy potency


Species Family Allergy potency
Maple* Aceraceae Moderate
Alder* Betulaceae High
Birch* High
Hornbeam* High
Hop-Hornbeam Low/Null
Hazel* High
Eastern Baccharis Composate Moderate
Cade Cupressaceae High
Mediterranean Cypress High
Arizona Cypress High
Juniper Low/Null
Whitecedar* Low/Null
False Acacia* Fabaceae Low/Null
Chestnut* Fagaceae Low/Null
Beech* Moerate
Oak* Moderate
Walnut* Juglandaceae Low/Null
Paper Mulberry* Moraceae High
White Mulberry* Low/Null
Ash* Oleaceae High
Olive High
Privet* Moderate
Pine* Pinaceae Low/Null
Plane** Platanaceae Moderate**
Poplar* Salicaceae Low/Null
Willow* Moderate
Yew* Taxaceae Low/Null
Japanese Red Cedar Taxodiaceae High
Lime* Tilliaceae Moderate
Elm* Ulmaceae Low/Null

*several species
** plane pollen is has a low allergy potency. But, microneedles contained in the linters coming from the degradation of female capitulums of the previous year are very irritative.


Spontaneous Herbaceous
Species Family Allergy potency
Gosefoot* Chenopodiaceae Moderate
(Salsola kali)
Ragweed* Composate High
Mugwort* High
Oxeye daisy* Low/Null
Dandelion* Low/Null
Mercuries* Euphorbiaceae Moderate
Plantain* Plantaginaceae Moderate
Grasse Poaceae high
Sorrel* (Rumex) Polygonaceae Moderate
Nettle* Urticaceae Low/Null
Pellitory High
*several species


Ornamental Grasses
Species Family Allergy potency
Reed canary grass Poaceae High
Reed grass Moderate
Tufted hairgrass High
Sand Ryegrass Moderate
Fescue* High
Oatgrass High
Hare's tail Moderate
Giant feather grass Moderate
*several species


Recognize treesand grasses with allergenic pollens

You can download by clicking on the links below posters that will allow you to recognize the trees and grasses emitting allergenic pollen (in French), with an indication of the allergy potency related to the pollens.

Download the poster of trees

Download the poster of grasses

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