Page 21 - GM Summer flipbook 2024

Mow as needed and support pollinators year round
Average # Flowers per Plot
GTI TRIAL AND RESULTS
Last spring we did a trial at the GTI where some plots of Kentucky bluegrass were left unmown until June. For the cut plots, the mower was set at 2.5” and the mown turf was cut weekly. By the end of May, 2023, the #NoMowMay treatment reached a height of 11”. Turf quality and the number and species of weeds were evaluated from April 13th to August 30th. For this trial, the most plentiful species producing flowers in the month of May was the common dandelion (Taraxacum officinale). Dandelion flowers produce plentiful pollen, but unfortunately the nutritional quality for our native pollinator species is relatively low.
Dandelions are often viewed as a nuisance in managed turf because they are so tolerant to mowing. The basal rosette escapes damage from the typical mowing height and when dandelions are mowed, they respond by redirecting energy into new growth and the production of additional flowers. It’s like cutting the head off the hydra! This survival strategy allows dandelions to continue reproducing and spreading, even under conditions of regular mowing. In the mowed treatments in our trial, the number of dandelion flowers was slightly reduced – but this does not mean that the number of dandelion plants declined.
Dandelions were plentiful in May and black medic bloomed in June. There were only slight differences in the number of flowers produced in each treatment on May 23 and 24.
An interesting observation from our #NoMowMay trial was that all dandelion plants in a turf stand will typically bloom at the same time, called a “flush”. Therefore, timing mowing around their blooming cycle could be an effective strategy for managing their spread while still supporting beneficial insects with pollen resources. Multiple waves of dandelion flowers appear 2–3 times throughout the growing season, with the first being around midMay (Note: for southern Ontario). By mowing directly after the flowers close, we can prevent dandelions from producing seeds while still providing pollen sources
GreenMaster • CGSA • 21