Sowing wildflowers into existing grass
This can be done in three ways:
Yellow Rattle (Rhinathus minor)
Yellow rattle is an annual species that produces attractive yellow flowers, seeding usually in July. The plant is semi-parasitic, with its roots coming into contact with grass roots and removing nutrients for its own use. In this way yellow rattle can actively stunt and suppress grass growth.
Being an annual, yellow rattle needs to be allowed to seed every year before cutting. It is important therefore to note that meadows containing yellow rattle should not be out until after July. If the species is cut or grazed before it seeds, the species will be absent from the meadow in the following year.
Plug plants can also be used to introduce wildflower species into a grassland, ideally with the use of yellow rattle.
Plug plants are raised in trays of between 150-200 small plants with a planting rate typically between 6-15 plants/m2 depending on budget. The best season for planting plugs is in the Autumn as there is less chance of the newly planted plugs being subjected to prolonged dry weather whilst establishing. The root system does develop over winter leaving the plant well equipped to face competition from the growing grass in the spring. Early spring planting is also acceptable, however, care should be taken to water plants in well and to ensure the plants don’t get swamped by the more aggressive grass plants. Planting in late spring/summer should be avoided unless substantial “spot” irrigation can be administered.
As the name suggests a scrape is an area where the ground is disturbed and wildflower seeds are sown. Ideally, the top layer of turf is literally scraped off and the soil underneath is worked into a tilth and new seed is sown. Alternatively, you can rotovate a strip or area and sow new seed into that area or degrade the existing sward with a heavy scarifier and sow seed. Scrapes can be any size or shape depending upon requirements. The areas around the scrape can be managed in any way depending upon the desired effect. If you want the area of wildflowers to spread it is recommended that you keep the surrounding grass area tidy but not intensively mown. Appropriate management would be 4 -6 cuts a year down to 40mm -70mm and on each occasion create some soil disturbance (scarify), this stops the surrounding sward becoming too thick or tight and facilitates the spread of perennial wildflower species, as well as creating an environment for new seeds to germinate. This disturbance is especially important toward the late summer and autumn.