Updated: Jan 10
Many people who come to us for advice, and have done their research, mention Yellow Rattle.
This is a semi-parasitic (and beautiful) annual wildflower, meaning it lives it's life in one year before re-seeding.
What is it parasitic on? The answer, is grass. And this is the magic of Yellow Rattle, because in drawing nutrients from grass without permission, it weakens them considerably. The effect is obvious, wherever patches of Yellow Rattle flower.
Why does this matter? Well, for 2 reasons.
First, restrained grasses don't out-compete other wildflowers in the meadow.
This is particularly useful on rich/dense grassland sites, such as converted paddocks or lawns.
However, we choose our language carefully. Notice we don't say "it helps the other wildflowers in the meadow".
Because in some cases, the opposite is true, and Yellow Rattle can interfere with the growth of a few unfortunate varieties. Bird's Foot Trefoil is one such wildflower, according to some studies.
So, we do NOT always recommend the sowing of this magical little plant - which looks like a yellow 'dead Nettle' - because it only needs sowing in volume on certain sites, where the benefits outweigh the complications it can bring.
To work, studies and our experience show that there is quite a narrow window to sow Yellow Rattle effectively. This is in August. It can work done in July or September also.
Before sowing, the grass must be ripped open in places with a rake or harrow. Then trodden, to ensure the seed contacts some bare earth.
Then you leave it, and it just appears, apparently from under the grasses. Like magic, from late May in warm years, through to July when it turns to brown seed-heads (beautiful in their own right - and you can gather and re-sow).
You often get a minor second flush of Yellow Rattle, for some reason, as late as Aug and Sep, but not always, and we don't know why!
We recommend you consult us, before sowing, or to decide if you should.
There is a second way to establish Yellow Rattle, and that is to buy plants. WE SELL THESE IN OUR ONLINE SHOP.
Plugs can be planted in the Spring (in April and May). The best sellers (we include ourselves!) sell plugs with native grasses growing alongside your Yellow Rattle plant.
This is a) necessary for good growth, as the Rattle parasitises the grass, and b) is a great way of introducing different native grasses, with their various types of beautiful seed-heads, into your meadow project.