ER WATERS

and frogbit (hydrocharis). Another three quarters of the sides, at least, should be planted with emergent and marginal plants such as irises, flowering rush ( Butomus umbellatus) and water forgetme-not ( Myosotis scorpioides). You should add some bunches of submergents such as spiked water milfoil ( Myriophyllum spicatum), not to be confused with the highly invasive parrot’s feather ( M. aquaticum). Fish, especially carp, will gobble these up, though, so you may need to cage the plants. I originally planted lilies directly into the soil on the base of my pool some 30 odd years ago, using a rampageous white water lily. Now I have contained them in baskets so we can see some water. These vigorous lilies start pushing their leaves way up out of the water when they become congested and every few years we lug them out, split and replant them in the spring. Some gardeners think their pool base should look like the bottom of a clean bath. This would be quite horrible for wildlife. What they really want in the base is about 150mm or more of good, healthy hydrasoil (mud!), which, if you have left it untouched, you probably have anyway. If you are not sure, take a scoop out and smell it. If it stinks of rotten eggs or methane, then maybe you have some anaerobic or partial decomposition. In which case add some Aquabio (calcium sulphate, from Agagroup). You have just time now to add it, or wait until late summer; it will slowly sweeten it. Planting marginal plants directly into the soil, which covers the whole pool/pond base, gives a better balance. Small quantities of basketed plants can look rather wimpy. Topsoil is too rich and makes everything turn green, and clay subsoil and fish are a bad combination, as the clay fines cloud the water when the fish move. A poor, sandy subsoil is best. If you want to add marginal plants now, maybe to hide your liner, a great way to do it is to add pre-vegetated coir rolls. These are sausage-shaped 2m-long rolls, 200mm in diameter. They bend and can be fixed either just below water level, or partially above it and they will sprout wonderful, lush, emergent plants (ornamental and native mixes, from the Aga group). If you are starting a new pool or pond, the choice of liner is very important. Butyl has been superseded; EPDM rubber is far better. It is not degraded by UV light and has a 25-year guarantee. Make sure it is 1mm thick. I always specify a blanket underlay (NP 300) below and usually above the liner too. If labradors, children and deer are going to stray in, it protects the liner. For more of Bunny’s gardening advice