Water Gardening In Summer

June

With such late starters as hydrocharis, azolla, sagit-taria, and the pygmy lilies becoming available, all aquatics can now be moved and June is the peak of the pond-planting season. Watch the foliage of the smaller lilies and miniatures for signs of attack by midge larvae.

Damselflies (the slender, delicate-looking members of the dragonfly group) may be seen fluttering over the pool. Pairs may be seen flying in tandem, the tail of the male grasping the ‘neck’ of the female. If the female’s body dips to touch the water periodically she is depositing eggs. There’s no harm in this.

Turn over almost any lily leaf in the summer and the chances are there will be sausage-shaped, jellylike objects underneath. They are not slugs, but the egg capsules of the water snail Limnaea stagnalis. If the capsules are flattish, round and amber coloured they belong to the Ramshorn snail, Planorbis corneus. Fish will take most of the pinhead-sized baby snails as they emerge. If you have a plague of limnaea get rid of the ‘sausages’ and also leave bruised lettuce leaves and stumps in the pool overnight. You will be able to gather a rich harvest of adult limnaea in the morning.

July

Time spent lazing in a deckchair by the pool can be justified by the need to keep an eye open for water lily beetles on lily leaves and the great diving beetle or its larvae.

Ripe seeds can be collected from orontium and aponogeton and simply deposited in an inch or two of water over soil in a plastic bowl. They will settle and sprout when they are ready.

Some growth of filamentous algae is always likely to be present, but if blanketweed becomes rampant rake it out. But do not dump it on the compost heap until you have sorted out any fish fry that were lurking among its strands.

If there are plum trees in the vicinity blackfly (aphis) will turn up on the leaves of water lilies and such marginals as sagittaria. Turn the garden hose on, put your thumb across the end, and blast them off with the resulting high-pressure jet. They will float in the surface film unless they are taken by fish, or by pond skaters and water measurers. These small (I in. or less) thin leggy black creatures, so light they walk on the surface film, are snappers up of unconsidered trifles like tiny insects that fall on the water -such as aphids. The blackfly that survive will crawl up any stem they bump into, and you will have to use the hose again because it is too dangerous for the fish to spray insecticides round the pool.

A spell of close thundery weather makes fish gulp furiously at the surface. They are not after food, but oxygen, which can suddenly become critically short in these weather conditions. Since oxygenators do not produce oxygen during the hours of darkness,

fish may even be found dead in the morning. In this crisis use the forceful hose jet again, to agitate the surface violently and mix in atmospheric oxygen. At night leave the hose, tied to the handle of a fork stuck in the ground by the pool, splashing a steady trickle into the water from 2 or 3 ft. above the surface. Or install a fountain and leave it on at night while the close muggy weather lasts.

All aquatics can still be planted.

August

From now on it is well to be conscious of the fact that an accumulation of decaying plant remains may, when winter ice covers the pool, have serious consequences for the fish. So, as lily blooms and leaves come to the end of their individual lives, don’t let them sink and rot. Pull them, complete with stems, and add them to the compost heap. Many oxygenators are now a declining force and will steadily die back. If left in the pool they will consume, in the process of decay, more oxygen than they will produce. So cut them back severely and have the bulk of them out of the pool. But not hottonia or callitriche.

Very few hardy lilies produce good seed, but the white miniatures Nymphaea pygmaea alba and N. tetragona do so regularly. As soon as the seeds are dark green, almost black, spread them (complete with their coat of jelly) on a pan of wet soil and cover them thinly with sand. Place the pan very carefully in a shallow tank so that there is about an inch of water over the soil. Seedlings will be ready to plant out by next June – provided that the tank is kept absolutely free of water snails. Break the brown seed pods off any iris you particularly like: the seed heads of waterside primulas are worth collecting too. If you have a frost-proof frame or greenhouse seeds can be sown immediately. Otherwise hang the seed heads in paper bags (where mice can’t get at them) until the spring.

The dedicated pond watcher may be lucky enough to witness the transformation of a dragonfly nymph into the perfect insect. It is worth watching. The nymph climbs clear of the water up the pool wall or the stem of a plant and rests in the sun for a while. Then the skin splits behind the head and the dragonfly heaves and works its way out to leave the nymph skin quite empty, but perfectly shaped in every detail, still clinging to its stem. It may be an hour or two before the emerged dragonfly’s crumpled wings have extended and dried enough for it to set out on its first wavering flight. If it escapes the sparrows it will soon be hawking for flies over the pool with tremendous speed and power. It seems able to do the impossible – change from full speed in one direction to full speed in the opposite direction without a pause.

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