Water wise gardening with trees & large shrubs

South Africans have become used to the El Nino effect causing havoc with our seasons. The amount of rainfall we can expect during the wet season differs in all regions. Many of our towns are still struggling with extreme water shortages, and don't have enough water to even keep a household going.

Luckily, we have had relief from the devastating drought in many provinces and it is giving us hope. Many people do still love to garden and new home owners living in shiny new estates want to green the environment around them.

Our industry is busy adapting and changing to keep up the greening in our water scarce country. 

The term water wise is not foreign to landscapers, but the general public needs our assistance through awareness and education in order to bring more greenery back into our cities and small towns. 

What is encouraging for a company in the 'mature tree market', such as Trees South Africa, is that established large trees & shrubs have survived the drought conditions without any irrigation.

Street trees in Somerset West that have survived the drought and are an asset to the suburbs.

Why are trees water wise?

The best method to become more water wise is to plan your garden according to the local climate and the water needs of plants. As trees and shrubs make up the backbone of every garden, they would be the most important plants to select when you are planning to redevelop an existing garden into becoming more water wise.

Trees provide shade as the canopy grows, reducing the evaporation rate from shaded garden beds. When used as a windbreak they shelter plants from the prevailing winds and reduces the rate of soil moisture loss. Working for Water has developed a wonderful program to remove alien invasive trees, some of which are large water users and drain our resources. Even though program is helping to save water, we do need to look at replacing the trees, to prevent soil erosion.

The network of roots they have developed helped to hold the soil together and prevented precious soil from blowing and or eroding away. Tree roots are also fantastic at reducing soil compaction and improving drainage and aeration as they slowly but surely move through the soil to anchor the tree and look for new sources of water. And lastly, the tree roots slow down water runoff and encourage water to penetrate the soil, thus allowing water to drain into the soil when it rains.

Trees in the Helderberg Basin after the drought and are an asset to the landscape.

Be water wise, plant more trees.  If we plant more trees, we will be able to make a vast difference in greening our cities and improving out climatic conditions, as many horticulturists have done in countries drier than ours.

Suzanne-Francoise Rossouw-Moss, Trees SA.
Trees in Somerset West that have survived the drought and are an asset to the landscape.

Cool your landscape 

During the process of photosynthesis, trees take up water, and water vapor is released back into the atmosphere through the leaves as part of the process when transpiration takes place. As a result, the surrounding area will be cooled down, thus creating little microclimate in the garden/towns/ cities. If trees are cut down, less water vapor will be released in the atmosphere making the climate drier and reducing the chances of rain in that area.

When it is not raining (as in the dry Mediterranean climate conditions in the Western Province), watering of newly planted trees will be key to its establishment and survival. Trees can show little or no new growth for years if not watered correctly but establish much faster if they are watered at a low irrigation rate, allowing the water to drain deeper into the soil. 

Drip irrigation is the best method of watering all plants in a water wise garden. U have less wastage and less water is lost to evaporation. You will also water less often if you provide plants with deep watering. It is very important to plan for a separate watering station when planting trees, as they will require longer watering periods than small shrubs and groundcovers. 

Once fully established it is no longer necessary to water trees at all, resulting in trees that can withstand drought conditions.

Trees in parks in Somerset West that have survived the drought and are an asset to recreation areas.

What to plant?

When it comes to the selection of trees for a water smart garden, look at species suitable to the local climate and the soil conditions in the garden. Most people will say you can only look at indigenous species, but if you consider exotic species that are also from a similar climate, they will also be suitable. Several exotic trees actually use less water than some of our indigenous species. We have a vast difference in climate throughout our country, but many trees can survive and adapt to a great variety of conditions.

See below a list of some of my favourite water wise trees.

Acer buergeranum, Afrocarpus falcatus, Afrocarpus latifolius, Apodytes dimidiata, Brachylaena discolor, Buddleja saligna, Buddleja salvifolia, Celtis sinensis, Combretum erythrophyllum, Combretum kraussii, Curtisia dentata, Cupressus sempervirens 'Stricta', Cupressocyparis leylandii, Dias cotinifolia, Diospyros whyteana, Dombeya rotundifolia, Dovyalis caffra, Ekebergia capensis, Erythrina caffra, Erythrina lysistemon, Ficus natalensis, Ficus sur, Ginkgo Biloba, Grewia occidentalis, Halleria lucida, Harpephyllum caffrum, Hibiscus rosa sinensis, Ilex mitis, Kiggelaria africana, Kigelia africana, Loxostylis alata, Magnolia grandiflora, Malus domestica, Metrosideros angustifolia, Nuxia floribunda, Olea capensis, Olea africana, Platanus x acerifolia, Plumeria rubra, Prunus africana, Pyrus communis, Quercus acutissima, Quercus canariensis, Quercus ilex, Quercus nigra, Quercus palustris, Quercus robur, Quercus suber, Rapanea melanophloeos, Rauvolfia caffra, Salix mucronata, Salix babalonica, Senegalia galpinii, Schotia afra, Schotia brachypetala, Searsia lancea, Searsia pendulina, Sideroxylon inerme, Syzygium cordatum, Syzygium guineense, Tarchonanthus camphoratus , Trichilia emetica, Vachellia karroo, Vachellia sieberiana, Vachellia xanthophloea, Vepris lanceolata, Virgilia divaricata, Virgilia oroboides, Ulmus parvifolia.

If planned correctly trees will make a great attribute to any private garden and landscape development. If we plant more trees, we will be able to make a vast difference in greening our cities and improving out climatic conditions, as many horticulturists have done in countries drier than ours.

Be water wise, plant more trees.

Contact Trees South Africa.


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