Create your own garden wetlandComment on this story
Cape Town -
February 2 was World Wetlands Day.
This year’s theme is “Wetlands and Water Management”, with the international slogan “Wetlands take care of water”.
This year’s national event specifically celebrated the successes of a 12-year rehabilitation project undertaken in the Kromme River wetlands in the Eastern Cape. Situated between the Tseerenuis and Tsitsikamma mountain ranges, the Kromme River wetlands are a catchment for 40 percent of the water used by the Nelson Mandela Bay Metropolitan area (Port Elizabeth), which is stored in the Churchill Dam.
At a ministerial function in Kareedouw, Eastern Cape, Deputy Minister of Water and Environmental Affairs Rejoice Mabudafhasi paid tribute to teams from Working for Water and Working for Wetlands who have been working on this rehabilitation project since 2001.
By removing hectares of invasive alien species and building gabions to re-flood drained floodplains, the teams have restored the successful functioning of the Kromme River wetland.
Moreover, the rehabilitation has saved large stands of palmiet, a unique wetland plant species that is regarded as the superglue of all Cape wetlands.
Why is it necessary to save wetlands? First, wetlands are the second most biodiversity-rich ecosystem in the world, after forests. And second, wetlands act as natural filtering systems and perform all the functions of a dam, by holding water for long periods and slowly releasing it in drought periods.
The importance of wetlands in gardens is not lost on a new generation of gardeners, and water gardening is the fastest growing sector in garden centres in Europe and the US.
Creating a wetland, marsh or bog in your garden is one of the most wildlife-friendly measures that you can implement. Develop a mini-bog garden next to an existing pond, which can overflow into it, or you can make an entirely separate marshy area.
Create a wetland
The simplest wetland can be achieved – and justified in these water-wise times – by directing rain water from roof downpipes into a depression (natural or scooped-out), forming a shallow pond.
You can also sink a number of wooden tubs, cut in half, and link these with a channel, siting these “ponds” below a garden tap.
Once filled, they may need to be topped up occasionally by opening the tap briefly. Allowing them to overflow obviates the breeding of mosquitoes and, to justify what may be considered wasteful opening of taps, edible plants like rhubarb can be introduced.
In very small gardens, wooden tubs with a few small drainage holes could accommodate one or two striking moisture-loving plants. Put in a layer of rocks, then fill with thoroughly wet soil. Surround with pebbles.
Old sinks complete with drainage holes also make good mini bog gardens.
For a larger marshy area, lay plastic in a depression. Consider these step-by-step instructions for making a bog garden with plastic this weekend:
* Mark out the required shape with string or sand, and dig a trench about 1m deep with sloping sides.
* Line the trench with black plastic sheeting, and make holes in it for drainage by piercing it with a garden fork at one-metre intervals.
* Replace the soil and allow the nearby pond to overflow slowly into this area so that it is constantly wet. Alternatively, if your bog garden is separate, fill it with water and top it up whenever the soil surface is dry.
* Attach rubber tubing to the downpipe of your gutter, and put the other end in the bog garden to direct rainwater into the bog.
If the bog is next to your driveway, you can direct the water from the driveway to the bog with low concrete swales (mini humps).
What to plant
From a plant perspective, boggy marsh wetland areas in your garden can be divided into four zones, each with its own group of plants.
* Zone 1: Free-floating aquatic plants are suspended in the water and absorb all their nourishment through fine roots, such as indigenous oxygen weed (Lagarosiphon major).
* Zone 2: Marginal plants have roots that are adapted to living in the waterlogged soils in submerged containers in a pond, such as the Cape water lily.
* Zone 3: Waterside bog plants thrive in mud – a water-logged airless environment that is quite distinct from the aerated, moist, well-drained soil present in other areas of the garden. Try white arums, water sedge (Cyperus spp.), Cape sedge (Elegia capensis), scarlet river lily (Hesperantha coccinea), Louisiana irises or the water-loving indigenous marsh lily (Crinum campanulatum), the seeds of which germinate in the mud.
* Zone 4: Water-loving plants are those that will not tolerate constantly waterlogged boggy soils, but can be planted between the garden and waterside bog plants. There are legions of plants that delight in the not-too-sodden (moist but not saturated) margins of a shady bog. Try the red hot poker (Kniphofia), indigenous cyperus, aristea, Cape thatching reed (Elegia tectorum syn. and Chondropetalum tectorum), wild iris (Dietes grandiflora), Dissotis canescens with lasiandra-like flowers of bright mauve-purple, crinum, Lobelia cardinalis, ferns, clivias, ajuga, thalictrum, primulas, streptocarpus, foxgloves, violets, Japanese anenomes, hostas, ligularia or astilbe.
Even water-loving shrubs such as hydrangeas, rhododendrons and roses can form a useful zone between the boggy pond area and the rest of your garden. - Weekend Argus