Management of meadows and grassland
Management by mowing or grazing is essential to the maintenance of structure, balance and diversity in grassland. Without management grassland becomes coarse and rank, loses both diversity and interest, and will eventually turn into scrub or woodland.
Shakespeare, Henry V
The even mead that erst brought sweetly forth
The freckled cowslip, burnet and green clover
Wanting the scythe, all uncorrected, rank
Conceives by idleness, and nothing teems
But hateful docks, rough thistles, keksies, burs,
Losing both beauty and utility.
The number and timing of cuts required each year will depend on soil fertility (how fast the grass grows) and site objectives. More cuts will be needed on sites with fertile soil and for a tidy managed appearance. Low profile sites on poor soils need less mowing. There is considerable scope to vary the pattern of mowing and grazing both from one spot to another and from one year to another to create different effects - experiment to find what suits your site.
The aftercare of sown grassland has two components:
- first year management
- management of established grassland.
These two phases of management require different mowing regimes.
First year management
Meadow mixtures are composed mainly of perennial grass and wild flower species which take at least a full year to establish from sowing. Do not expect plants to develop enough to flower in their first summer.
Mow regularly throughout the first year of establishment; this will help maintain balance between faster growing grasses and slower developing wild flowers. Quick growing meadow components will tolerate cutting and may even benefit from this ‘pruning,’ pushing them to develop more robust compact plants. Mowing to remove surplus top growth will give smaller slower growing plants more light and space to grow into.
In the first summer meadow mixtures sown on to bare soil are frequently dominated by a flush of annual weeds which come from the soil. Regular mowing will remove annual weed competition and prevent them seeding.
Mow to a height of 40-60mm. Ideally collect and remove arisings to avoid leaving behind a damaging mulch of decomposing cut grass. If you can mow frequently enough it may be possible to disperse the cuttings without leaving a mulch. The number and timing of cuts will depend on site productivity, weather, manpower and equipment available. Mowing can start as soon as there is enough growth of either weeds or sown species to take a cut.
Where cornfield annuals have been sown as 'nurse cover’ with a meadow mixture cutting must be postponed from spring through to mid-summer to permit flowering. These sown annuals should be cut back and removed promptly once flowering declines (typically late July). Do not wait for the annuals to set seed and, if the growth is lush and begins to collapse, cut and remove sooner rather than later to avoid them smothering and killing the meadow seedlings below. Once the annual cornfield cover is cut back and the cut material removed, the sown meadow species will be revealed as small green plants, separated by bare ground. These seedlings will then have an opportunity to grow on through the latter half of the growing season using the light and space provided.
Yellow rattle is an exception in meadow mixtures, being annual rather than perennial. Where yellow rattle has established well from an autumn sowing avoid mowing between late April and mid-July to give it a chance to ripen and shed seed for the following year. Where there is an over-riding need to mow through this period to control growth, replacement yellow rattle seed can be sown in the autumn.
Sowings into existing grass can be managed as an established meadow, with perhaps extra cutting or grazing where growth is lush.
Management of established grassland
The second year from sowing is the first in which a sown meadow is left uncut to flower, and a first "hay crop" taken in mid summer. The early years of a sown meadow (years 2/3 from sowing) are characterised by the more quickly establishing pioneer perennials such as oxeye daisy and sorrel, and the growth is vigorous. In following years the meadow will become more diverse as slower establishing species like cowslip appear and growth is less vigorous as nutrients become fixed in root systems and herbage.
The character and composition of the meadow will continue to change with time. Eventually a relatively stable community will develop, the balance of which will reflect management, soil fertility and the natural environment of the site. In this way the outcome of each sowing will in practice differ, and will not be a direct reflection of the species balance in the sown mixture.
A mowing regime for managed grassland will contain one or more of the following elements:
- A main mid-summer hay cut
- mowing or grazing of the regrowth 'aftermath' in late summer and autumn
- mowing or grazing of lush spring growth
Summer hay cut
The main cut each year is the summer "hay cut". This is when the main part of the year's growth is cut back using a scythe, heavy duty strimmer, reciprocating knife or other suitable mower (lawn mowers are generally not up to this task). The growth should be cut back to a height of 40-75mm.
The cut grass should be dried on site, turning it to assist drying and disperse seeds (this also significantly reduces the weight and bulk of material to be removed). The dried 'hay' should be removed within 7 days of cutting. On larger areas it may be practical to cut and bale quality hay. Where hay making is impractical, arisings may be composted or placed in heaps on sacrificial parts of a site, where if you are very lucky they could provide habitat for breeding grass snakes! A meadow will yield 2 - 8 tonnes of dry hay per hectare (0.2 - 0.8 kg/m2) A 250m2 (tennis court size) meadow will produce about 5 x 25kg hay bales (typical small square type).
Timing of the summer hay cut
There are a number of conflicting factors that determine the best time for the main hay cut. The choice is always a compromise between these factors: in our view the best solution is wherever possible to mow in sections at different times through the season from late June to the end of August. This maximises variation and diversity on your site and spreads the workload over the summer making larger areas manageable even with simple equipment such as a scythe.
Early hay cutting commencing in late June produces the best hay feed quality with optimum sugar and mineral content. Hay removal at this optimum time also means the maximum harvest of nutrients from site which may be important in the longer term for the fertility balance of the soil. However early cutting brings a premature end to enjoyment of the flowers and can compromise nesting birds which don't fledge until late July as well as insects and other wildlife using the meadow. Mowing a meadow in sections at different dates prolongs the overall flowering season and gives wildlife a chance to move aside. Start by cutting lush areas where nutrient removal will be of most benefit. Areas with dense, lush or laid vegetation are also likely to be the least attractive to nesting birds.
Mid-summer hay cutting. The period from July into early August is generally the best time for mowing meadows for both wildlife and practical hay making considerations. Evidence suggests that this is the optimum time for maintaining floral diversity. If mowing in sections over time, as we advise, aim to cut the biggest proportion of the meadow during this period.
Late hay cutting in August and September when the meadow is ‘over-stood' is more difficult as the plant stems become dry and tough. Grassland which is consistently cut late in the season year on year looses species diversity as late cutting gives more time for coarse grasses and other dominant plants to grow unchecked. Whilst in the short-term later cutting avoids any disturbance to birds and insects, in the long term the richness of the meadow as a source of pollen and nectar is lost, also the coarse structure of the sward becomes less attractive to breeding birds. Again varying the mowing times both within the meadow and from year to year is the best way to maintain a diverse balanced sward.
Haytime summary to maintain maximum diversity and flowering interest mow the meadow in sections at different times from late June to the end of August. Do not cut meadows in May or early June as you might disturb nesting birds. The main mowing season is July. To maintain flowering interest and balance it is best to complete hay cutting by the end of August. Parts of the meadow may be left occasionally (one year in three in rotation) into September so that late flowering species can seed. Leave some patches or edges uncut through winter to provide winter refuge for insects.
Thin open swards, that stand well and retain interest, can be left longer than dense or collapsing vegetation. If the grass collapses because it is too lush or because of bad weather a hay cut needs to be taken sooner (this is most likely with young swards on fertile soils). With the exception of yellow rattle (which seeds early) most meadow species are perennial and do not need to set seed each year - some species will last indefinitely in a meadow without ever setting seed.
After the main cut, additional mowing or grazing during late summer and autumn is very effective in removing excessive grass growth and encouraging flowers -particularly on more fertile sites. Mow with a rotary, flail or other suitable mower to 40-75mm. Ideally cut at least twice from the time the hay is removed to the end of November, aiming to leave the grass short through winter. The amount of mowing required will again depend on the fertility of the site; areas can be mown regularly (weekly) if a more tidy appearance is wanted. If any cut produces significant quantities of material this should be removed
Spring cutting to remove the first flush of grass can produce a later flowering meadow that is shorter, more open and less prone to collapse. Spring cutting or grazing is particularly useful on more fertile soils and in the early years of newly sown grassland; on settled infertile sites this may be unnecessary. The need to mow can be assessed by the amount and type of growth in the spring. Mow with a rotary, flail or other suitable mower to 40-75mm. For meadow grassland mow around Easter, and no later than the first week in May. For short flowering turf and pasture grassland, regular mowing or grazing may continue into June provided the grass is kept short enough to discourage use by nesting birds.
With the exception of the annual hay-cut, grazing with animals is always better than mechanised mowing. Most grazing animals (even rabbits in moderation) can produce some benefits to sward structure and development through recycling of nutrients and opening gaps with their hooves. Meadows and grassland can be maintained by grazing alone. Either graze at a low stocking density through the season, or close the meadow to stock from spring to July /August for more flowers (sheep often selectively eat flowers!).
In the absence of grazing the base of swards tend to become dense and matted. The accumulation of dead material (thatch) prevents the re-establishment of yellow rattle and other perennials, resulting in a progressive loss of flowering plants. Grazing is often impractical, particularly in urban areas and on road verges. In these circumstances the action of hooves can be simulated by harrowing or scarifying. Late autumn is the best time to harrow as it creates gaps which remain open to flower seed germination from autumn through to spring. There is an opportunity to add seeds to grassland at this time. Meadows were traditionally harrowed in spring to level mole hills and make mowing easier in summer.
On most soils there will be some initial problems with perennial weeds. Most grassland weeds such as docks and thistles are suppressed by the annual hay cut in July and will gradually decline with good management. Low level weed populations may be spot sprayed with a herbicide, or pulled (eg ragwort). Selective herbicides are only worth using as a last resort for serious infestations as they will result in the loss of many wild flower species. more
Other grassland regimes
Meadow management is not the only grassland option. Sites sown to meadow mixtures can be managed in different ways from year to year, and from one area to another. Cutting frequency and timing can be used to create structural and species diversity and interest, and to extend the flowering season.
Meadow mixtures mown regularly to a height of 25-40mm throughout the growing season become flowery lawns. This is useful in landscaping edges and pathways for access. Mowing should be relaxed from late June to allow flowering, resuming cutting again when the sward gets untidy. Mowing may also be suspended earlier in the year to allow cowslips to flower.
With this cutting regime plants such as knapweeds which are normally tall at flowering flower at a reduced height; plants like selfheal and birdsfoot trefoil respond by flowering prolifically. If you treat part of your meadow like this, for example as a path, you can always re-site this short area/pathway in following years to a different section of your meadow. For dedicated flowery lawn sowings mix EL1 mix is available.
Established grassland that is not mown or grazed each year will become rough and "tussocky" in character. This grassland type is not as diverse or attractive as meadowland, but once established requires minimal maintenance. This can form useful refuge habitat on corners and margins of a site. Unwanted perennial weeds (docks, thistles) may need control by occasional spot treatment with a herbicide. To control scrub and bramble development tussocky areas may need cutting every 2-3 years between October and February. For wildlife this cutting is best done on a rotational basis so that no more than half the area is cut in any one year leaving part as an undisturbed refuge. Mowing established tussocky grassland may require heavy duty cutting equipment: lawn mowers are not tough enough to deal with thick tussocks or woody scrub. Tractor mounted flail mowers are suitable for large areas, petrol brush cutters (professional 'strimmers') are good for small or awkward areas. For dedicated tussocky grassland sowings mix EM10 is available.