Know your pollens: a resource for hayfever sufferers

Hey, do you know that there are pollens and there are pollens, and not all pollens are to blame for your hayfever symptoms? As I have written before, the pollens of your typical spring flowers in the garden are too big and too heavy to be airborne, and therefore, can’t be really airborne allergens. The bad pollens are those that come from the trees and grass. And the timing and severity of your hay fever symptoms would depend on where you are and the plants growing around you, the time of the day, temperature, and yes – rain. Those who are sensitive to these minute particles would have an immune reaction that induces the production of histamine, prostaglandin and leukotrienes.

Now, let us take a look at the two groups of pollens that cause your hay fever, what they are, and when they become a nuisance.

The Tree Pollens

According to the hay fever expert (UK), 20% of hay fever cases are due to tree pollen allergies. In the UK and many parts of Europe, the trees most likely to produce hay fever agents are

• Birch
• Alder
• Yew
• Elm
• Hazel
• Oak
• Horse chestnut

The birch tree pollen is especially a problem for residents of the British Isles and Scandinavian countries. Tree pollens are mainly responsible for spring hay fever. High season for birch tree pollens is between March and May and worst in the month of April. The oak pollens come later, in May. In the southern part of the US, the oak accounts for more pollens (65% or more) than all other tress combined. The most common pollinator trees that can cause hay fever in southern US are (in order of importance, source, Davidson et al, 1934, Southern Medical Journal):

• Oak (March to May)
• Hickory (April to May)
• Poplar or cottonwoods (February to April)
• Box elder or water ash
• Sycamore
• Birch
• Maple
• Willow
• Ash
• Elms
• Hazelnut

 In Japan, the pollen of the cedar tree seems to be especially bothersome at this time of the year.

The Grass Pollens

The summer and autumn hay fever are mainly due to pollens released by weeds and grass plants. In the UK, the main causes of hay fever  are the xx. In southeren US, the Bermuda grass are the bane of hay fever sufferers. There are many species and varietiess of grass and weeds that produce pollen allergens. The pollens are carried by the wind and transported to our eyes and nose. The grass speices most commonly associated with hay fever in southern US are:

• Bermuda grass
• Johnson grass
• June grass
• Annual blue grass
• Orchard grass
• Perennial rye grass
• Crab grass
• Sweet vernal grass
• Timothy grass

The Weed Pollens

In Switzerland and in the US, ragweed seems to be the most bothersome. In southern US, the most common hay fever-associated weeds are (in order of importance):

• Ragweeds (short and high)
• Marsh elder
• Cocklebur
• Spiny amaranth
• Red root or rougb pigweed
• Careless weed
• Lamb’s quarters
• Jerusalem oak
• Mexican tea
• Red sorrel, or sheep sorrel
• Yellow dock
• Bitter dock
• Annual sage or wormwood

As mentioned before, your symptoms will all depend on where you are and what pollens you are sensitive to. Here are some resources you might want to check out:

• Tree Pollen – Hayfever Expert (UK)
• Grass Pollen – Hayfever Expert (UK)
• Horn, E, 1933. A Summer hay fever plant survey of Manhattan, Kansas. Elsa Horn. Transactions of the Kansas Academy of Science (1903-), Vol. 36, (Apr. 13-15, 1933), pp. 91-97.
• Davidson et al, 1934. The Principal Hay Fever Plants and Pollens of the South. Southern Medical Journal