Listening to frogs in French water gardens

reprinted by kind permission of Peter J May, the Perfect Pond Detective

Hi, me again, and it is June. Sizzling in the UK, today is the sort of day that inspires headlines in the newspapers the following day like “It aint ‘arf hot Mum!” and “PHEW! Wot a Scorcher!” under pictures of lardy holiday makers at Brighton or Blackpool roasting themselves bright red in the sun. The temperature? All of 80°F, under 27°C!

I’ve just been roasting in the south of France, that’s why these chronicles are late. We stayed with friends that wined and dined us every night in their rustic farmhouse in the Charonte. Every evening we ate by the side of their water garden and as the our conversation became more animated, so the noise of the frogs became louder and louder, until eventually we’d be competing at the tops of our voices. We’d stop dead occasionally, either in complete frustration or to marvel at the cacophony, and there would be instant silence, then slowly the noise would build up again. The pool was full of scores of edible frogs and little tree frogs around the sides. The edible frogs could make two styles of burping noise, one by blowing up a sack under their mouths and the other by blowing up cheek balloons. It was possible to use both devices at the same time or consecutively, either way giving each frog seemed to have the vocal power of two frogs and the volume potential was above that of the average human voice. The net result was the impression that the pool was heaving with these animals and that they seemed determined to demonstrate that it was more fun being a frog than a human being….It seems to me that this is the year of the frog for me. They have haunted my every move this year, so much so that fish and plants seem only to be part of the picture in the water garden world.

If you’ve have a potentially good harvest of froglets from tadpoles this year, now is the time that they will start to emerge from the pond and sit indecisively amongst the surrounding sward of lawn, so take care with your mower as you fly by the pool or fire up the barbeque in anticipation of a feast of mini frogs legs!

Of course this is the time of the year that Aquatic retailers eagerly await the return of their early season customers who only bought a pool and a few plants. They return in their droves looking for submersible pumps for fountains, waterfalls and filters. As the weather warms up the new fish start gasping at the surface despite them following all the recommendations of getting in the right number of plants and especially oxygenators in the water.

Allow one bunch of oxygenators per 0.2 sq m (2 sqft) of pool surface

Allow one lily for every 2.3 sq m (25 sqft) of pool surface.

Marginals: allow at least one plant for every 0.5sq m (5 sqft).


But in a new pool especially with Koi carp and even if it has a filter system, if the fish have been added before the whole system has matured, the pool has to go through a phase where the ammonia level rises before the bacteria that break down that ammonia get well established. Now it is a good idea to add one or two fish to start the whole process going because it is their faeces and fish food that produces the ammonia that the bacteria feed on, but these are ‘Kamikaze’ fish in the sense that the environment you have introduced them to is going to go through some pretty unhealthy phases before it gets robust enough to support a full population of fish at 2inches per square foot of surface area. The worst bit is when then the ammonia is partly broken down to nitrite chemicals and you have a cocktail that is poisonous and damaging to the gills of the fish. This is when they start gasping. So the best action is to follow you instincts and get plenty of oxygen in there. Large partial water changes are best, but running water in hard from a hose is also good. The oxygen will sustain the fish and also provide the bacteria in the bottom of the pool and the filter if you have one, with the essential oxygen they need to make the chemical break down. The next phase is the break down of the nitrites to nitrates, which is then greedily absorbed by the plants. PHEW!

So if you haven’t got a fountain or a waterfall and you have some precious fish recently installed, think about it. And if you have created this watery habitat for the sake of some beloved fish, then seriously think about a biological pool filter, especially if it gets any warmer than it does here in the UK. The other deciding factor maybe that without a filtration system, you pool needs to be two thirds covered by plants at this time of year in order to maintain a balance and provide anywhere near clear water. Allow 4 to 6 weeks for a pool to really establish it’s microbiology. The are proprietary ‘pool starter’ mixes available to get things going, or try borrowing a couple of gallons of water from a friends pool that you have so long admired. Adding this will be like a yoghurt starter. My friend Tony Roocroft at practical water gardens in South Africa tells a tale that spitting into the pool can have the same effect. Apparently the bacteria we carry in our mouths are pretty much the same as those found in the bottom of a pond!



JOBS FOR THE MONTH

Dead head early flowers like the Marsh Marigolds and irises. Now begins the period where water gardeners look enviously at their friends with bog gardens that can work as a spectacular backdrop to a pool. The flower and foliage affects that can be achieved here carry of much further into the season with some plants only just beginning to come into flower. Things like the Day Lily – Hemerocallis, Rodgersia, Ligularia and Hosta. However water gardeners still have their lilies to enjoy and these can still be planted. Some of the old time water gardeners would only think of planting lilies at this time of year.

Look for pests on leaves. Aphids can be abundant on lily leaves and marsh marigolds. Knock them of with a harsh sprayer or a finger and thumb. The fish will soon gobble them up.