Yellow Rattle
About Yellow Rattle
Yellow Rattle is an attractive annual of hay meadows. It is partially parasitic on some other grassland species and will often reduce the vigour of coarse grasses, resulting in transient dominance of Yellow Rattle in areas across a field. Each area triggers a succession, allowing other species to establish in the vacant niches left by Yellow Rattle.
Historically seen as a pest for farmers due to its impact on hay yields, Yellow Rattle is now appreciated for its ability to enhance wildflower displays and reduce necessary mowing.
Yellow rattle germinates late February to early March, flowers in June, and sets seed in July. At the end of each growing season as the annual yellow rattle plants die away they leave behind gaps into which new wild flowers can establish. As a result, wild flower seed sown into an existing sward will establish more readily in areas where yellow rattle already does well.
Getting Yellow Rattle Started
Establishing Yellow Rattle can be unpredictable, taking two to three years to build up plant numbers. Success depends on the chosen sowing rate and site conditions.
Tips for success:
1. Site Selection: Yellow rattle will not thrive in all grassland. The most suitable sites for yellow rattle will be managed grassland of low to medium fertility that contains a balanced sward of finer grasses, not dominated by coarse or vigorous grass (ryegrass, cocksfoot, tall oat-grass or couch). Grassland that is the result of sowing a meadow mixture will have suitable grasses, as will finer turf in gardens and meadows. Yellow rattle often fails to take in ryegrass leys and neglected, over-grown or tussocky grassland.
2. Preparation: Cut or graze the sward in the autumn, aim to keep the grass short (40-50mm). Create gaps across the site with exposed soil for yellow rattle seed to germinate in. This can be achieved by autumn/winter grazing with stock (their hooves open the sward), or mechanically by harrowing or raking, aiming to expose up to 50% bare soil.
3. Sowing: Yellow rattle seed is best sown in the autumn as it needs prolonged chilling through the winter to trigger its germination the following spring. Sowing can also be done through the winter months depending on the season and the availability of periods of frost post sowing. The seed should be scattered onto the prepared surface at a rate of 0.1 to 1 g/m2. Consider re-sowing in the autumn of the first year for better results.
Yellow rattle may be sown as a component of meadow mixtures on to a prepared seedbed. First year meadow management (mowing) can compromise seed set of yellow rattle. To be sure of getting yellow rattle in the second year, it is best to re-sow yellow rattle in the autumn of the first year (as above). Where cornfield annuals have been sown as a ‘nurse crop’, yellow rattle has more opportunity to self-seed.
To order seed please visit the Yellow Rattle species page.
