Developing Grass-Free Lawns

Removing grass from lawns in-effect creating a grass-free lawn can have a number of benefits. Following research at the University of Reading’s School of Biological Sciences, it is now possible to transform these ‘green deserts’ with a mix of carefully chosen flowering plants.

Vast Areas Of Desert

Lawns are the most common feature of urban green space worldwide. In the UK, estimates suggest that domestic gardens occupy more than 414,000ha, and that lawns occupy up to 60% of that garden space.

UK domestic lawns, therefore, potentially cover up to 248,000ha, an area approximately one and a half times the size of Greater London, and more than seven times the area of local nature reserves in England. That’s an area big enough to stand in the middle of and see nothing but turf lawn to every horizon.  In places like the USA more accurate satellite mapping indicates turf covers an area bigger than entire countries. Turf covers more land in the USA than the total area of England and Wales combined.

‘Improving’ Lawns

The term ‘industrial lawn’is often used to describe the monoculture that is the ‘ideal’ grass lawn.  This is due to the large amount of energy, resources and management techniques that are required to maintain it to an ideal standard. The ideal lawn has also been described as a ‘green desert’. A highly managed grass lawn does not provide much in the way of above-ground habitat and flowers can be the unwelcome indicator that weeds have crept in.

However, not all lawns are so stringently maintained. In the UK the common garden lawn is regularly found with lawn weeds such as buttercups and daisies, but what would happen if the traditional approach to achieving the ideal lawn were completely turned on its head? What would happen if all the grass was removed from the common garden lawn and the other plants that can be found there, the weeds, were allowed to mingle and thrive? What would happen if those plants were carefully selected and their traditional status changed from weed to chosen plant? How might this influence lawn management, plant choice and wildlife in the garden?

Lawn Alternatives

There are a surprising number of grass-lawn alternatives. Perhaps the most familiar to UK gardeners would be chamomile or thyme lawns, but elsewhere in the world, it is possible to find peanuts, beach strawberries and ferns used in a similar manner. These lawns may sound exotic but they are easily identified as lawns since they are low-growing, ground-covering and replicate the familiar monoculture format; they also show human intent, design and ongoing care. These human factors are almost more important than the plants themselves since without these guiding cues it can be challenging to immediately appreciate what we are seeing.

When the traditional cue of mown grass is removed from the lawn what are we left with? A bunch of weeds perhaps, or, if we are a little kinder, a group of wildflowers? Let us suppose that this bunch of common native lawn weeds includes daisies, buttercups, white clover and cinquefoil.

What do we have if the daisies are the fashionable peach-pink of Bellis perennis ‘Robella’, the buttercup the delicate pale yellowish white of Ranunculus repens ‘Gloria Spale’, the clover the dark-leaved Trifolium repens ‘Atropurpurea’, or the cinquefoil with the double flowers of Potentilla reptans ‘Pleniflora’? Do we still have a bunch of weeds, or do we have a selection of carefully chosen ornamental plants? If we continue to mow these plants to keep them neat and tidy do we still have a lawn? If so, we now have a grass-free lawn that is a selected community of mowing-tolerant plants with the potential to produce flowers. The green desert has been transformed.

Regime Change For Mowing

This transformation has consequences. The architecture of grasses requires frequent mowing to keep them low, it is the cue that tells us that they are part of a lawn rather than untended grasslands, but forbs (non-grasses) have a different architecture. They do not require the same frequency of mowing. Research has determined that grass-free lawn communities require up to two-thirds less mowing compared with traditional lawns.

The number of cuts per year a grass-free lawns requires can be reduced from  20 to 30 cuts a year.  A grass-free lawn is more likely to require five to nine cuts. It is essential that the clippings are removed to allow in light. This reduces considerably the amount of energy required to maintain a lawn and can lead to a reduction of four-fifths in CO2 emissions from fossil fuels associated with mowing.

The role that mowing plays in lawn management is also transformed. Instead of simply maintaining lawn height, the mower acts to balance the competition between plants that can be expected in any plant community. Some species, such as white clover, can get relatively tall quite quickly if left to their own devices and would soon shade out lower growing and less vigorous species; mowing acts to moderate this. Taller growing plant species are more severely affected by the mower than lower ones and take longer to recover from its effects. Mowing repeatedly allows light to reach plants that would otherwise be shaded out. A community of plants with different characteristics to coexist in a manner that is not possible without a mower.

Plant Characteristics

Mowing places limits on the type of plants that can be used in grass-free lawns. 

First and foremost, grass-free lawn plants must be mowing tolerant; they should be able to recover between mowing. Secondly, if long-term persistence is required they need to be able to reproduce: either by seed in the window of opportunity between mowing, or to be able to reproduce clonally. Daisies, buttercups, white clover and cinquefoil are able to persist in grass lawns because they can produce stolons in addition to setting seed.

Influence Of Species

The number of species used within  grass-free lawn plant community can greater influence  it. Without intervention, the strongest competitor in a small community of plants can come to dominate. However, as more and more species are added and competition increases, the competitive advantage any single species has is reduced. Experiments suggest that a minimum of 12 different species should make the basis for a grass-free lawn. However, much more can be included, which allows for some quite creative ‘lawn gardening’.

The role that each species plays in a grass-free lawn has been found to fall into one of three categories. Some plants are useful for their flowers, some are useful for ground cover, and some can provide both. A mix of all three types makes for the most aesthetic and useful grass-free lawn. Plant species or cultivars with large leaves, vigorous growth, or which grow taller than 9cm are excluded. Alpine plants can also prove difficult. They tend to suffer root rot in the cold, water-saturated soils of a typical British winter.

Biodiversity Benefits

The habitat and resource opportunities for wildlife are also changed: a greater diversity of plant species, substantially reduced levels of mowing, and flowers as a component of the lawn, . The number and variety of insects that are found in grass-free lawns are greater than that found in domestic lawns. This offers insectivorous birds an improved food resource.

The floral resources available to pollinators are also dramatically increased.  Grass-free lawns receive 80 times more visits from pollinators than grass lawns and more than twice as many as “flower lawns”(grass and wildflower mixes). In one survey 45 pollinator species utilised experimental grass-free lawns. Just eight pollinator species were found to visit traditional grass lawns.

A mature grass-free lawn (three or more years old) can absorb rainfall three times faster than bare soil. It is also twice as fast as a traditional grass lawn. During short periods of drought, grass-free lawns can stay green when grass lawns become crispy and brown.

Construction Of A Grass-Free Lawn

Currently, the best method of constructing a grass-free lawn uses plants grown in single-species trays. A random mosaic is created by laying them like carpet tiles on subsoil.  You should allow plants to establish themselves without being competitively overwhelmed. More importantly, it allows for the use of selected cultivars and non-native plants that are propagated from cuttings. It also creates new opportunities for lawn design. For the most part, this method was used to create the 100m2  grass-free lawn that can now be seen in Avondale Park, West London.

Conclusion

With the research complete and the benefits of grass-free lawns established. Will gardeners embrace such a radical departure from the traditional lawn? Perhaps in the near future, there may be a little less grass and a lot more flowers in your lawn.

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