The effects of cutting on pollen and seed production in ragweed
An Agriculture and Agri-Food Canada study obtained significant results in a greenhouse experiment involving the cutting of ragweed. Plants measuring 25 cm tall were cut to a height of 10 cm just before flowering. A second cut was made when plant regrowth had reached 25 cm in height.
These two successive cuts delayed flowering by 17 days and reduced the number of flowers.
Pollen production was reduced by a factor of 9 in the cut plants.
Cutting was associated with a decrease in the number and mass of seeds in a plant. Viable seed production was reduced by a factor of 5 in the cut plants. However, cut plants produced enough seeds to replentish the soil. This method will not reduce the number of plants present the following years.
In summary, mowing twice - once before flowering in mid-July and 15-20 days later around mid-August - considerably reduce the amount of pollen released in the air.
© Her Majesty the Queen in Right of Canada, 2011
Cat. No. A52-188/2011E-PDF
AAFC No. 11485B