Seventy years ago, wetlands were considered to be insect-ridden, unattractive, and dangerous areas. An estimated 50 percent of SA wetlands were drained for extensive farming, but by 2000, wetlands were regarded as one of the country’s most threatened habitats.
World Wetlands Day is celebrated on ThursdayFebruary 2 with the theme of the celebrations being “Wetlands and Tourism”. The theme reflects a dramatic change in public opinion over the past 50 years and showcases how valuable wetlands have become to communities.
Not only do they contain a variety of plant and animal species, but wetlands control erosion, absorb floodwater, purify water by filtering out toxins and release water in drought periods. Like giant sponges, they hold water when rivers run full, and release it, cleaned and recharged, when levels are low – thereby preserving the river and rejuvenating its flora and fauna.
Garden wetlands
Bog gardens have been a part of suburban gardening for decades.
The key to developing and maintaining a thriving wetland or bog garden is to develop an understanding of marginal plants.
Marginal plants – often called bog or marsh plants – are plants that flourish in a site where the water level is slightly above the level of the soil level into which they are planted. They also include colourful plants such as red hot pokers (Kniphofia spp), elephant’s ear (Alocasia spp), arums and hostas, all of which like damp soil on their feet in water during their growth season, but prefer to be dry during their dormant season.
The range of marginal plants available for a garden wetland is much larger than the range of plants that actually live immersed in water. Many gardeners now choose to develop indigenous wildlife ponds that lie next to ponds or even slope into ponds and attract birds, butterflies and dragonflies. It is in these ponds that marginal plants are so increasingly useful.
Marginal plants
Many of the plants available in garden centres as ordinary garden plants are in fact marginal plants, and will thrive if placed in planting baskets just below the water level.
* Creeping Jenny (Lysimachia nummularia) – a good ground and water plant particularly in its gold form.
* Crocosmia spp are exceedingly tolerant of marginal areas. About 40cm tall, with spiky foliage and yellow, orange or red flowers in summer.
* Acorus gramineus and its cultivars – grasses that form a low tussock of arching leaves – are popular plants with persistently bright variegated leaves.
* Many Lobelia spp make excellent marginal plants. The dark-leafed red L splendens syn fulgens and L cardinalis have always been popular plants for the border but look perfect in the water, either set off against Acorus gramineus “Variegatus” or yellow-leafed creeping Jenny.
* Louisiana iris does particularly well in boggy gardens. Among the five species that make up that group, there is a dazzling array of colours and sizes available.
For decades gardeners have come to love the stately pickerel weed (Pontederia cordata) with its spear-shaped leaves and blue flowers in summer. Declared a Category 3 invasive species, the pickerel weed can no longer be traded or moved, but existing species can be left in garden wetlands.
Indigenous marginals
There are also a host of indigenous marginal plants to use in a wetland. Look out for the Gunnera perpensa, bulrush, common reed, yellow-bloomed blood root, pink-flowered water crinum, Cape water lily and white arum.
Among the better-known marsh or marginal plants are the indigenous reeds (Cyperus spp), many Crinum spp, many Juncus spp, Kniphofia linarifolia and K typhoides. Also try the Lobelia flaccida, otterbossie, ouhout, tongblaar, Minopsis lutea, Cape fuchsia and wild date palm (Phoenix reclinata). - Saturday Star