Water-Wise Lawn Tips

In most South African gardens, lawn areas make up a large portion in the garden. By reducing the amount of lawn or replacing some of it with either hard surfaces or ground cover you could save water.

This is by no means a drive to do away with lawned areas completely, as they are important for recreational activities. But where possible avoid cool season grasses. Select indigenous, hardier varieties of grass like Tifwolf LMG, which is a low-maintenance grass requiring less mowing, or other Cynodon or Kweek species, Phyla nodiflora, and matgrass or carpet grass. 

Reduce the mowing height of lawns to decrease the water use rate. Frequent cutting of lawn reduces stress. Cutting the lawn down by more than one third will also cause undue stress. Homeowners should also avoid watering their lawns during the winter months, until well into the next rainy season.

Give lawn the lowest priority when it comes to landscaping because it is slower to die, recovers easily and is usually less expensive to replace than other vegetation types. Use hardy groundcovers rather than lawn in difficult areas or consider ornamental mulches.

Water Wise shares tips on how to create a water-wise lawn…

Creating a water-friendly lawn

1. Cool season grasses have a different metabolism and will use more water than a warm season grass. Cool season grass also uses as much as 12.5mm of water a day compared to a warm season grass which varies between 2.5mm to 7mm of water use per day.

2. Lawn must be suitable for the area.

3. Only water lawn as required i.e. just as signs of dryness or leaf stress (leaf curl) set in. Some grasses such as Cynodon start to turn a blueish colour when they need water. If you stand on the grass and your footprints remain behind after a few minutes thereafter, take this as a sign that your grass needs watering.

4. Don't over-water lawn as fungal diseases may occur, resulting in poor growth.

5. Cool season grasses such as All Season Evergreen and Shade Over need to be watered for 2 minutes daily and receive 1mm every day for 6 days and on the 7th day to apply 19mm of water.

6. Other grasses such as Golf Green, Bayview and Cynodon species only need to be watered once a week for 20 to 30 minutes and receive 20mm to 25mm of water. You can place a rain gauge on the lawn to assist with this process.

7. Allow lawns such as Kikuyu 20mm to 25mm of water once a week.

8. In winter, reduce all watering quantities by half, and water cool season grasses weekly. Water Cynodons and Kikuyu every second week.

9. Reducing the height of lawns is directly proportionate to the amount of water a lawn uses. For the above, the cutting height is recommended as follows: cool season grasses should be 40mm in sun and 60mm in shade, Cynodon species should be 7mm and Kikuyu 15mm in height.

10. To improve clay soils, hollow tine the lawn and replace the cores with a good mix of compost and river sand. This allows some of the water to remain and improves the drainage of excess water. Gypsum (agricultural lime) can also be used if dug into the soil.

11. Sandy soils are best watered in small amounts more often. Clay soils are best watered in larger amounts less often. Use cycling as a method of watering.

Why plant ornamental grass

Ornamental grasses are a natural choice for water-wise gardens because not only do they require little water (if well chosen for the site) but also little maintenance. They need no deadheading (removal of spent flowers to promote continued bloom) or mowing, and they are pest and disease free.

They accommodate a wide range of soil and climatic conditions. Grasses are one of the most successful plant families in the world. There are grasses in nearly every environment, from the hard baked desert to soggy marshes, from the tropics to the polar regions, from the seashore to the highest snow covered mountains. Grasses are therefore available for each water zone in the garden.

In general, species from the family Gramineae (true grasses) will be the most drought tolerant, or will be found in the driest regions of the world. Their needs are simple, they only need fertile, well-drained soil in an open, sunny location.

Bamboos and the grass-like plants in the Carex (sedges) and Juncus (true rushes) genera, in that order, need progressively more moisture in the soil. The Luzula genus (woodrushes) and Typha is more adaptable, tolerating wet feet next to a stream and some drought if established in rich soil under trees.

Using grasses in the garden allows for any type of design, from formal to cottage, symmetrical, indigenous, to wild and natural. Most grasses, especially the smaller varieties such as Ophiopogon should be planted in groups and not as single plants. To create some contrast, place with other plants of larger leaf size or colour. To enhance the effect of the grass, plant large groups of different types in a similar bed or area. 

Site consideration 

1. Make sure the grass is correctly chosen for its own microclimate.

2. Plant ornamental grass for texture, line and architectural elements.

3. Plant extra wild ornamental grass for birds and insects in your garden.

4. Trim back grasses once a year if required.

5. Be aware of water grasses with creeping stolons (stems) in pools with plastic lining as they can create holes and leaks. 

How to save water and maintain your lawn

1. Use a screwdriver to test the depth of watering. The screwdriver will penetrate the soil more easily when moist.

2. Don't compact lawn by parking cars onto it.

3. Don't cut the grass below 4cm in height or more than one third at any time because this reduces root depth, causing stress on the lawn.

4. Aerate the lawn in spring or early autumn by pushing a garden fork into the soil (preferably when wet) at a spacing of 25mm and a depth of 100mm.

5. Check your lawn for thatch. This is an accumulated layer of dead material at the base of the turf that can reduce water infiltration. If necessary, de-thatch the lawn in spring. This can be done with a garden rake, but for best results use a commercial machine.

Article courtesy of Property24