Weed control has always been a major issue for my customers. Whilst some forms of weed and plant life will encourage wildlife, by providing food and oxygenating your pond, there are several types of weeds and plants that will always try to run rampant over your pond or lake, either in the water or on the banks. Whilst my skiffs are often used for weeding ponds, my punts are designed to provide a working platform for more serious weeding and bank maintenance. So I often visit ponds and lakes with heavy weed issues!
Blanket weed is probably the most common nuisance weed. It is generally caused by excess nitrogen and phosphates in the water. Blanket weed looks like a layer of green slime/algae sitting on the water. It floats on the surface and blocks out the sunlight, preventing it from penetrating the water.
The best way to tackle blanket weed is to get a nice long rake with fairly fine teeth and simply pull it straight out of the water.
Plant lilies, marsh marigold, water soldier, or any other oxygenators in your pond. These plants will create oxygen, which in turn will encourage almost all other forms of life in your pond or lake.
Excess Nitrogen and phosphates can come from using plant fertilizers on the banks of your pond or lake, the nitrogen in the fertilizer is then washed into the pond, which then encourages the algae. Fish food can also contain nitrogen, so using excessive amounts of fish food can increase the problem. Tap water can contain elevated levels of nitrogen, so consider using rainwater to top up your pond, rather than resorting to the hose.
Remove floating dead leaves from your pond at intervals during the autumn months. As the leaves decompose in the water they will release nitrogen.
A common way to prevent future growth of blanket weed is to use barley straw. This can be brought in pellet form, but usually comes in the form of a small bale of straw in a net, you simply put the bale onto the surface of your pond. It will float at first, but after a month it will sink and decompose. As the Barley straw decomposes it will release compounds which help to absorb the nitrogen in the water. (some bales of barley straw come with a little float, so the bale stays close to the surface as it decomposes). This will reduce blanket weed naturally. You will need to consult the manufacturer or retailer to ensure you have the correcct number of bales for your lake or pond, as they come in different sizes.
Grass carp, tadpoles, and rams horn snails will eat blanket weed (along with almost anything else they can find).
Once you have raked out your blanket weed, leave it by the waters edge, that way invertebrates that live in the weed can escape back into the water.