Grassland and vegetation management are very important in the maintenance of any traditional orchard.
Effective management prevents the grassland converting to scrub, helps support the floral diversity and enables you use and enjoy your orchard to its potential. An overly mown orchard floor is not great for the wildlife, but harvesting windfalls from long, wet, and nettle filled grass is not to be recommended either so to an extent, orchard floor management will be a compromise.
If you have a good knowledge of the plant communities your orchard supports then you can manage your grassland according to these. For example, if you know you have some orchids in that patch behind the gate, or some ladies smock in the gappy area in the far corner, you can tailor your mowing around them, making sure they have had enough time to flower and set seed. Otherwise, the following advice will generally help maintain the biodiversity you are likely to have.
- The grass needs to be cut at least once annually to prevent large woody plants establishing and converting your orchard into scrub. Whilst a low level of scrub can be good for biodiversity, if you let it encroach on your orchard too much your species rich grassland will become overgrown and dominated by tall grasses and scrub as the herbs and fine-leaved grasses are outcompeted. Scrub also makes it more difficult to manage your trees and harvest your fruit.
- Dry the grass cuttings on site and turn them to help the seeds disperse, then either remove the cuttings from the site, use them to mulch directly below your trees or compost them in a corner of your orchard out of the way.
- It is important to remove the grass cuttings from your orchard grassland, if they are allowed to rot down they will enrich your soil which can lead to a loss in plant diversity. Over time you will lose your wildflowers which prefer poorer soil and gain plants like nitrogen loving nettles instead. Low soil fertility, despite sounding like a bad thing, is actually a crucial feature of semi-natural grassland, which is of great conservation value.
- Herbicides and fertilisers should be avoided as far as possible, as should rolling and harrowing. Rolling and harrowing can harm the often shallow roots of fruit trees through compaction and mechanical damage. They can also disturb invertebrates in the soil, damage ant hills and, depending on the time of year, affect nesting birds or destroy fallen fruit that would be eaten by birds through the winter.
- In general, diversity of habitat correlates with diversity supported by the habitat. So within reason and practicality, the more varied you can make your orchard floor in terms of structure and plant communities, the greater diversity of insects, small mammals and birds could potentially be supported.
Staggered and late mowing, as well as leaving a strip of rough grassland will help create this habitat structure. Below is some information about these approaches as well as some sketches of what it might look like to apply these to your orchard. Importantly, these sketches do not need to be followed precisely, but aim to simply demonstrate the ideas; you do not need to mark any areas out or fence anything off, but instead use this as a rough guide. Equally there is no harm mowing in pathways or picnic spaces into any of these areas, it is important that you manage your orchard in a way that suits your use of it, be this recreation, the fruit, for biodiversity or a mixture of all of these.