WATER GARDEN CALENDER and CHRONICLES (September) by Peter May

Remove any dead leaves before they sinkto the bottom of the pond.Now September is a time for clearing off decaying vegetation on plants in and around the pond. Some of the marginals could have been cut back to one third and may have flowered again. With very small ponds, if you can reach the dying leaves of the lilies or the faded flowers see if you can snip them off before they fall to the bottom of the pool. Dont tug on them too hard as this may damage the rhizome.

This year some of the trees in the UK, particularly birch and mountain ash are calling an early close to the season. This means small leaves blowing around and inevitably into the pond. Try to make a routine of netting this off.

This adventitious growth could make a new plant is removed and potted up.You can collect offcuts from the plants if you want to propagate them. Just pull them off or cut them neatly as they emerge from a basket. If they have developed root hairs then they will be guaranteed to establish in any good heavy loam set in a well-drained pot sitting in about 2inches, 5cm of water.
It may be time to replace tired and overgrown plants in the marginal baskets next month, so these will be a useful replacement.
Lilies should be the main attraction now along with the Fringe lily, Nymphoides peltata. A few bog plants like the Ligularias, the Lobelias and Astilbes may be putting on a show. This is when the robust foliage plants like the Hostas, Rodgersias,Rheums, Peltiphyllum and Petasites come into their own.

Koi keepers want to be feeding fish with good quality food to build them up for the winter. Be particularly careful not to over feed as usual. As the water cools there may be a greater susceptibility to parasites and disease. Keep a close eye on them checking for signs of 'flashing', quick movements that involve flipping onto their sides or rubbing hard against the pond sides , rocks or planting baskets. This may indicate parasites. Look also for fungal growth and bits hanging off them. Any outward signs of malaise must be treated immediately.

Apart from the plagues of blanket weed this year, many people have been having trouble with duck weed. Now that the only really effective treatment for duck weed or Lemna has been withdrawn, the gardener isA barrow load of duck weed from a small pond.: If this was weedkilled in the pond, it would cause a significant pollution problem when it sank to the bottom. once more left to fend for himself with whatever ingenuity and energy is at his disposal. For both blanket weed and duck weed, before any cooler weather reduces the effectiveness of competing plants in keeping growth to a miimum, try to remove as much as possible. For those of you with large pond that perhaps have large areas of pure duck weed away from the planting areas of other plants, you can try a treatment of glysophate (like Roundup) to kill the plant. Glysophate is none toxic once in the water. Unfortunately the dead plants sink to the bottom and this may cause an algae bloom or a pollution problem when the material begins to rot. Ideally an efficient filtration system needs to be place to deal with this, the pond needs to be in an otherwise very healthy state and it needs to be done now whilst there is still plenty of biological activity going on.
If there was a duck weed treatment about that did work then the same would apply. I have tried a couple of new ones this year and they haven't worked, but more about that elsewhere. It will probably feature in the blog which is a domain especially reserved for tirades against rubbish pond products!

Hostas come into their own as foliage plants after all else has flowered: That is if they have not been decimated by slugs and snails

Petasites make a fine foliage plant later in the season even in a wild boggy area.

Lilies in the Sarah Duke Gardens at Duke University in North Carolina: These lilies are carrying on the late season colour well up to autumn. But here in North Carolina the problems of temperature come considerably later, hence tropical varieties are still flowering.