March 7, 2017
| On 2 years ago

Water wise gardening in South Africa

With many areas in South Africa quite dry at the moment, we need to save water at every turn. This must be applied to our gardens as well. When people think water-wise gardening they think of a garden covered with lacklustre succulent plants with no charisma. This does not have to be the case, as we have many charismatic and beautiful plants at New Plant Nursery that are also water-wise.

Plants that are good for water wise gardening can divided into five main groups; succulent plants, plants with small or needle-like leaves, plants with grey leaves, plants with hairy leaves, plants with waxy leaves and bulbous/tuberous plants. The growth forms of the plants also make a difference and using plants that fit into the above mentioned categories that are groundcovers also helps to keep water from evaporating from soil.

Succulents are uniquely adapted to live in dry areas because of their physiology. They have a special kind of metabolism called crassulacean acid metabolism, which involves the stomata in the leaves remaining shut during the day to reduce evapotranspiration, but opening at night to collect carbon dioxide. We have a great variety of succulent plants at New Plant Nursery that are looking good at the moment. These include Bulbine frutescens, various Cotyledon and Crassula species and a few different varieties of Portulacaria afra. Crassula pelucida creates an excellent water-wise groundcover and has a very attractive growth form and leaf shape.

To fully understand why small and needle-like leaves loose less water through evapotranspiration, it is necessary to understand the concept of surface area to volume ratios. These leaves essentially have a smaller surface area to volume ratio which means that there is less surface area to lose water from compared to more conventional leave sizes and shapes. Plants with small leaves that are available at the moment include Searsia crenata and Halleria eliptica and plants with needle-like leaves incudes our large selection of Agathosma, Coleonema and Erica species.

Plants with grey leaves are water-wise because grey leaves are more reflective than normal leaves, so that less light penetrates the leaf surface, thereby decreasing water loss through evapotranspiration. We have a great variety of plants with grey leaves in various shades of grey. These include groundcovers such as Osteospermum fruticosum and Helichrysum species, shrubs such as the Artemesia afra and Salvia species and trees such as Buddleja saligna.

Hairy leaves decrease water loss through evapotranspiration by essentially shading the leaves with their own hairs. Plants with hairy leaves that are ready to save you some water include Erica cerinthoides, Eriocephalus africanus, Helichrysum species, Leonotus leonorus and Pelargonium tomentosa.

The wax layer on leaves provides a physical barrier to evapotranspiration because of its impermeability to water. We have a large selection of plants with waxy leaves including our various species and varieties of Carissa, Grewia occidentalis, Jasminium multipartitum and Putterlickia pyracantha

Planting water-wise shade trees will allow you to plant less water-wise plants underneath them. Their shade will allow you plant plants that would otherwise lose too much water in direct sunlight. Trees that are available to suit this purpose include Cussonia spicata, Erythrina caffra and Syzigium cordatum.

Apart from using the right plants you can employ other strategies that will reduce your water use even further. You can increase the water-holding capacity of your soil by adding compost and decrease evaporation from your soil by adding mulch and groundcovers. Reducing the size of your lawn and only watering during the early morning and late afternoon also reduces the amount of water your garden uses.

We have the right plants and advice at New Plant Nursery to help your garden stay beautiful through this dry season.