Forage harvesters and lawnmowers were out in force in recent weeks on fine days with good, drying breezes. Rising temperatures and late spring showers, or more prolonged spells of rain, combined to make grass grow quickly.
Furthermore, nights are getting progressively shorter and warmer, so morning dews burn off quickly affording householders the opportunity to mow lawns and farmers to harvest grass for silage making.
Grass is an amazing plant in its ability to grow. When a grass seed germinates it grows roots, stems and leaves. The mature plant goes on to reproduce and it can do that in either of two ways, or in both ways at the same time.
First, grasses reproduce sexually. They produce flowers and the pollen is dispersed by the wind. Since the flowers don’t need to attract the wind, they are not colourful or showy and they don’t produce sweet nectar to attract bees and other pollinators. Pollen grains have to be small and light to get carried on a breeze so the flower parts are usually small and difficult to see.
By removing the flower heads, regular mowing and/or grazing by animals reduces the grass’s ability to reproduce sexually, so the plant resorts to Plan B: tillering. Tillers are shoots that grow from buds on what is left of the parent plants decapitated stems. Tillers can grow upwards and attempt to reproduce sexually. If that is frustrated by ongoing mowing and/or grazing, then the tillers grow out sideways forming a sod.
Tillers can produce their own roots, stems and leaves so they are constantly reproducing the parent plant in a vegetative way. Since no sex is involved, the process is known as ‘asexual reproduction’ or ‘vegetative propagation’. A grass seed has two parents whereas a tiller has only one; it is literally “a chip off the old block”.
Tillers that creep on the surface of the soil are called ‘stolons’ to distinguish them from ‘rhizomes’ that creep below ground. As they creep, the tillers send down new roots and send up new leaves causing the grass to extend sideways in an attempt to avoid the mowing and/or grazing from above.
The combined processes ensure that grasses manage to both survive and thrive. Growth will continue into autumn when falling temperatures and duller days will slow the processes for another season.