By Vimbai Ruvengo
Due to the Covid-19 lockdown a lot of people are working on their backyards most building vegetable and flower gardens. The biggest worry for most is the limited availability of water to create the desired lush flower garden, designed with green lawn and inundated with flowers that create a plethora of colours in the backyard. For those faced with water availability problems, xeriscaping is the answer to your flower garden needs.
What is xeriscaping?
“Xeros” is a Greek word that means “dry.” Xeriscape refers to a landscape that uses small amounts of supplementary water. This gardening technique seems to have ‘originated’ in the 1980’s as a result of ongoing, multi-year droughts that plagued the Western United States.
Studies in Nevada showed that installing xeriscape gardens reduced water bills by 50% and reduced labour time by 26.4%, since the gardens needed less maintenance like mowing and manicuring.
Xeriscaping incorporates seven water-conserving principles:
- Planning and design
Design the landscape with sections of differing water requirements-this is called hydro-zoning. Hydro-zoning is the grouping of plants according to their water requirements by creating zones. The first zone is an oasis, a zone with the highest water use and is usually where people spend more time. Beyond the oasis is a transition zone of moderate water usage. Further away may be a low-water-usage zone, which requires no supplementary water or very limited irrigation during prolonged dry periods.
- Soil preparation
Till the soil to loosen it for improved root development and better infiltration of water and air. Add some compost to the oasis and the transition zone to increase the water holding capacity of the soil. After establishment of plants, limit tilling procedures since soil disturbance promotes the germination of weed seeds
- Use of mulch
Mulch the plant zone – mulch provides a cover over the soil, which reduces evaporation and erosion and moderates soil temperature. It also limits weed growth and therefore reduces competition for water and nutrients. Use bark, gravel, and other porous mulches that allow water and oxygen to reach plant root
- Appropriate turf
On the oasis-zone use a turfgrass that needs less water such as buffalo grass or Bermuda grass. Surround water zones with decorative gravel, flagstone or pavers to slow rainwater, encourage water to percolate back into the soil without pooling or flooding and to prevent weeds from sprouting up.
- Water-efficient plant material
This principle ensures an attractive landscape that uses plants selected for their water efficiency and deciduous trees for providing shade. While you may use many of your old favourites in the oasis zone, there is a wide variety of colourful, fragrant, and beautiful plants for the less moisture demanding parts of the landscape.
Succulents (Xerophytes) – plants with thick leaves or stems to enable water storage. These include sedums (Sedum spp.), hens-and-chicks (Sempervivum tectorum), hardy ice plant (Delosperma cooperi) and the self-sowing annual moss rose (Portulaca grandiflora).
Small leafed plants – the diminutive leaves possess less surface area minimising loss of water e.g. thyme (Thymus spp.), Corsican stonecrop (Sedum dasyphyllum), candytuft (Iberis sempervirens), moss phlox (Phlox subulata) and mossy saxifrage (Saxifraga x arendsii). The moss-like feature of these plants makes excellent ground cover plants that can reduce soil loss of moisture.
Silver or grey-green leafed plants– this characteristic reflects the sun making them good xeric plants. Examples include most Mediterranean plants such as lavender (Lavandula spp.), Russian sage (Perovskia atriplicifolia), lavender cotton (Santolina chamaecyparissus), wormwood (Artemisia spp.) and lyme grass (Elymus arenarius ‘Blue Dune’).
Ornamental grasses – they can survive the heat once established and can easily survive purely on rainfall. These include blue wild indigo (Baptisia Australis), compass plant (Silphium laciniatum), Husker Red penstemon (Penstemon digitalis ‘Husker Red’), purple love grass (Eragrostis spectabilis) and blue grama (Bouteloua gracilis).
- Efficient irrigation systems, properly designed and maintained.
Irrigation is necessary in a xeric landscape; frequent irrigation routine is needed while the plant roots are establishing and lesser following establishment. The drip irrigation technique is encouraged as opposed to sprinkler systems commonly used on turf areas, but these systems waste considerable water due to over spraying and wind drift.
- Appropriate maintenance
Any good garden will require some maintenance: pruning, occasional weeding and pest management, checking that the irrigation system is functioning properly, and adjusting automatic irrigation systems as the season’s change.
Remember that gardening is a learning curve: as the garden grows so does the gardener.
The list of xeric plants is adapted from Xerascaping plants by Julie Martens Forney at https://www.hgtv.com/outdoors/landscaping-and-hardscaping/design/xeriscaping-plants.