Royal Ascot’s Lawns
Royal Ascot’s Lawns
The lawns in the public areas of Royal Ascot consist mostly of two species, Stenotaphrum secundatum (Buffalo grass) and Cynodon dactylon (Bermuda grass or “kweek”). Some of the lawns have the invasive Pennisetum clandestinum (Kikuyu grass), but this species is not encouraged.
During the hot summer months the lawns turn brown and we often hear people saying that the grass is dying; and lack of sufficient water is blamed for it. More water will make the grass greener, but the plants are not actually dying off at all.
To appreciate this, we have to understand some things about the ecology of grasses.
|The Ecology of Grasses|
|Grasses all belong to the family Poaceae – there are about 600 genera with over 10,000 species; Poaceae is the fourth largest plant family. They evolved more than 65 million years ago in the Cretaceous period; and have become established all over the world, particularly in grasslands covering about 31% of the Earth’s land surface – these are variously known as savannah, pampas, plains, prairie, steppes, etc. Grasses are not only a major food source for many wild animals, but it is the single most important plant family in human terms – more than half of all calories consumed by humans come from three cereals (rice, wheat and corn); and 70% of all food crops are grasses. It is the major source of carbohydrates for all humans, and the major source of protein for most humans in second and third world countries.|
|A grass plant grows from seed, but the root system also spreads underground by means of rhizomes, pushing up new plants at nodes, or by stolons or runners above ground which form a node with a new plant where it touches the soil. At each node a root system is also formed. In response to grazing pressure, grasses have evolved to grow their leaves from the base of the plant and not from elongated stem tips – this means they can be grazed (or mown) without damaging the plant. The plants can thus propagate themselves without seeding, a further adaptation to grazing.|
|The blades of many grasses are fairly short-lived, from only a few months up to about a year. But even if the part of the plant above the surface dies off completely during adverse conditions, the root structure remains healthy and regrowth will appear when conditions become suitable.|
|Buffalo Grass (Stenotaphrum secundatum)|
|Buffalo grass has broad flat leaves forming a thick mat which will crowd out most weeds and other grasses. It grows well close to the seashore, the flowers are adapted for seed dispersal by ocean currents for short distances. Like most grasses it now occurs all over the world in tropical and temperate climates, but it is said to have originated from southern Africa, although there is a difference of opinion about whether it is indigenous to South Africa or not.|
|It is a highly palatable grass and in nature is grazed by a variety of grazers. Buffalo grass is known as being tough and able to withstand periods of drought. As a lawn it must be allowed to form a thick mat, because of its flat growth pattern a buffalo lawn requires little maintenance; in fact one of the worst things one can do to a buffalo lawn is to cut it frequently. In the summer months in the western Cape the leaves turn yellow, the appearance of the brownish flowers (see right) further add to the “dry” look of the plant.|
|Bermuda grass or ‘Kweek’ (Cynodon dactylon)|
|The common kweek grass has grey-green spiky leaves growing from stems; it has a very deep root system and can survive for long periods in drought condtions. The grass does not come from Bermuda, the name derives from its abundance as an invasive species on the islands; it is thought to originate from north and east Africa and southern Europe, but now occurs worldwide in warmer climates. It reproduces through seeds, runners and rhizomes.|
|As a lawn grass it grows well in open sunlight, but not so well in heavy shade close to tree trunks. There are numerous varieties that have been developed for golf courses and lawns. It requires more maintenance than buffalo grass, but can withstand dryer conditions.|
|Watering the Royal Ascot lawns.|
|Although grasslands go through natural dry and wet periods and become yellow brown during the dry seasons, lawns can be kept permanently green by applying huge amounts of water. But in a water scarce country like South Africa, we simply cannot afford to waste water on keeping up the appearances of lawns.|
|When a lawn turns yellowish during hot dry spells, it does not mean that the lawn is dying. Some leaves might die off, but the plant itself is still very healthy and can survive for long periods without watering.|
|In Royal Ascot we do water our lawns, adhering strictly to the City’s Water By-Law (click here), and even in summer we keep to the guidelines set by the Municipality for watering public open spaces. They recommend that these areas should be watered for a maximum of one hour, and at the most three days per week.|
|The time of watering can be reduced drastically depending on soil conditions. In sandy quick-draining soils, a full hour’s watering could be required, but in clayey soils which retain water, this can be reduced to as little as 20 minutes. In Royal Ascot we have a mixture of soils – in some areas very sandy, in others quite a lot of clay (our soils in the residential areas are mostly fill that was brought in prior to development). But underneath it all are ferricrete layers that prevents water from draining quickly – this means that the water table in this area is fairly shallow, in areas only about 1,5m below the surface in summer, and about 0,5m in winter.|
|The soil conditions in Royal Ascot probably require about 30 minutes of watering per day for three days, but this is not necessarily the case throughout Royal Ascot as the soil conditions vary considerably.|
|During periods of strong south easter winds it may be necessary to increase the water regime slightly (but not to exceed the guidelines), the important thing is to monitor the lawns carefully and adjust irrigation so that the plants are maintained, even if the appearance is yellow and brownish.|