 Growing Gardens
with Julia Hancock
Pond Weeds
Plants in our region grow ridiculously quickly and undesirable aquatic plants are no exception. Now is the time to nip potentially larger problems in the bud and clean them up.
Azolla is a perennial fern that floats on the surface and is usually green in the winter but as the sun becomes stronger turns to a rusty brown-red. It can double its size within a week and before you know it, your pond is totally covered, which can be a hazard for children, the elderly and the unsuspecting who may think the pond is solid ground and fall in.
As with most curses, azolla has an upside – it makes an incredible nitrogen-rich fertiliser and mulch. The safest way to use it is to mix it into your compost heap to prevent it being washed away in a heavy rainfall and causing a hazard elsewhere. Any new plants you bring into your pond should always be checked for azolla infestation; it only takes one tiny piece to become a major problem.
Another invasive plant growing on the water's surface is Salvinia molesta, which is a major problem in ponds where the water contains high levels of nutrients which have leached in from adjacent fertilised garden beds.
In larger, more open areas of water Eichhornia crassipes, the water hyacinth, is an aggressive weed with rapid growth. In some regions its infestation has altered the entire ecology of the surrounding area.
Rather than use toxic chemical herbicides why not try the simple barley straw method twice a year in spring and autumn for organic weed control? Simply weigh down a bundle of barley straw and allow it to sink to the bottom of your pond to gradually knock out the nasties. If that doesn't work, then manual removal is the best alternative.
|
