Montreal, Quebec (lasalle region)
The tree pollen seasons can fluctuate from year to year by as much as two to four weeks at this site due to the effect of weather. The pollen seasons described here try to cover the time when each can occur.
Acer sp.- Maple season varies due to the number of species and the effect of weather. The season can start mid-March to the second week of April and end the third week to last week of May. The counts can get in the high range and some species are considered important in causing allergic reactions.
Alnus sp.- The alder season can start from mid-March to almost mid-April and end mid to late June. The season fluctuatues from year to year and the counts are usually in the low to moderate range.
Betula sp.- The birch season can start mid-Marh in warm years like 2010 and 2012. Generally the season start is from late March to the second week of April and ends late May to the third week of June. The counts get in the very high range. They are considered to be important allergens.
Birch look-a-likes sp.- The birch-look-alikes' season can vary a great deal from year to year. The season is mostly in May and moderate counts can be observed in certain years. Some species are considered allergenic.
Tsuga sp.- The hemlock season can vary from year to year. This is partly due to cyclical patterns and the effect of weather. Some years moderate and high counts are possible, whereas other years only sporadic low counts are observed. The season can start from early to late May and end late May to mid-June.
Carya sp.- The season for the hickories can vary in length and pollen levels from year to year. The season can start mid-May to early June and end mid to late June. Mostly low counts are observed, but certain years moderate ones are possible.
Castanea sp.- The chestnut season can start from mid-May to the second week of June and end mid-June to early July. The counts are usually in the low to moderate range but some years high numbers are observed. Some of the species are considered allergenic.
Populus sp.- The poplar, cottonwood and aspen season can start from about mid-March to early April and end early to late May. Very high counts are observed and allergic reactions can occur at these levels.
Cupressaceae family- The season for the cedars, junipers, and yews can start the second week of March to early April and end late May to early June. Some high counts are observed. Most species in Canada are not considered allergenic.
Fraxinus sp.- The ash season can start mid-Apil to early May and end mid-May to early June. High counts are observed and allergic reactions can occur in sensitized individuals.
Fagus sp.- The beech season can start late April to the second week of May and end late May to early June. The seasons fluctuate from year to year due to cyclical patterns and weather. Occationally moderate counts can be observed but most years the counts are low. At these levels they may not cause allergenic reactions.
Pinaceae family- The season can start late April to mid-May and end early to mid-July. Some of the counts do get high. These are important allergens to those who have allergies to this group of trees.
Quercus sp.- The oak season can start mid-April to early May and end late May to mid-June. Very high counts are observed and certain species are known to cause allergic reactions.
Salix sp.- The willow season can start from almost mid-April to late April and end late May to early June. Only low to moderate counts are observed so they may not cause allergic reactions except in individuals who are highly sensitized.
Ulmus sp.- The elm are important allergens. The main season can start early to mid-April and end late April to mid-May. Moderate and high counts can be observed in the main season.
Gramineae family- The grass season can start from early to mid-May and end early October. Moderate counts are observed from late May to mid-July. This site has another season with significant counts late August to mid-September. This species of grass is unique to certain sites.
Ambrosia sp.- The ragweed season can start the third week of July to early August and can end late October or when there is a hard frost. Moderate and high counts occur in August and most of September.
Artemisia sp.- The sagebrushes and wormwoods produce mostly low and the occasional moderate count from the first week of July to early October. May be a source of allergenicity.
Urticaceae sp.- The nettle and parietaria season can start from the first week to the last week of June and end late September. Moderate and occationally high counts are observed. They are considered important allergens due to their small size.
Plantago sp.- The plantains can be of significance in causing allergic reactions. The season can start late June to almost mid-July and end mid-September to early October. Only low counts are observed.
Diatrypaceae sp.- The counts are sporadic throughout the whole counting season. High counts can be observed from March to well into October. They are not known to cause allergic reactions.
Leptosphaeria sp. & Leptosphaeria look-alikes- These two are grouped together since they are in the same class of fungi and are similar microscopically. The season is April to late October with great fluctuations in counts from day to day. This is probably due to the effect of weather. The significant counts are mostly in the moderate range.
Erysiphe (Oospora) sp.- Powdery mildew - The season is from mid-April to mid-October. Significant counts are mostly in the moderate range.
Caloplaca sp.- Moderate counts occur from the end of August to mid-October. The season is sporadic and it may cause allergic reactions.
Coprinus sp.- This mushroom can produce high counts from May to late October. Considered an important allergen.
Ganoderma sp.- This bracket fungus can produce very high counts from June to late October. Considered an important allergen.
Uredinales sp.- The rusts do not occur in really high numbers and not enough is known about their significance in causing allergic reactions at these levels. The main season is from June to late October.
Ustilaginales sp.- The smuts can reach high counts, but allergenicity is unknown. The season is May to late October.
Alternaria sp.- The counts can get really high and some species are known to cause allergic reactions. The main season is from May to late October.
Penicillium sp. & Aspergillus sp.- These spores are found throughout the whole counting season and are probably present in significant numbers beyond that. Significant counts are observed from March to late fall.
Boletus sp.- The counts for this spore do not get very high but may be of significance in causing allergic reactions. The main season is June to mid-October.
Botrytis sp.- This may be a significant allergen even though the counts do not get very high. The season is July, August and September.
Cladosporium sp.- The most abundant spore found throughout the whole season. This spore exists all year round but the highest counts occur from March to late fall.
Epicoccum sp.- Not found in really high numbers but some species are known to cause allergic reactions. Season is July to late fall.
Fusarium sp.- Counts are very sporadic throughout the whole counting season. The majority of the season occurs from mid-June to mid-October.
Helicomyces sp.- Majority of season is from May to the end of September.
Pithomyces sp.- The main season is August and September.
Polythrincium sp.- Allergenicity is unknown but significant counts are observed from the end of July to the end of September.
Myxomycetes- Moderate counts are observed from March to September.
Last Updated: 3 March 2015
The information presented here is designed to inform, not replace, the relationship that exists between a patient and a medical professional.