After 5 years of dealing successfully with blanket and duck weed, a new challenge, potamogeton crispus, otherwise known as curly pondweed has appeared in the pond. A few plants appeared last year and the year before. This spring there are very large growths.
It is listed by the Royal Horticultural Society as troublesome and the advice us simply to pull it out to reduce the growth, though once in a pond it won’t disappear altogether. So when the water is a bit warmer, it will be waders on and into the pond to do some weeding. It is noticeable that the areas where I raked the bottom last November to clear debris there is almost none of the new weed, so that is another longer-term option.
The good news is that it’s quite easy to pull up and it also seems to blanket out blanket weed. Curly pondweed is sold as an oxygenator for small ponds and aquariums and only becomes a real nuisance in large ponds and lakes. Oxygenation is a plus, too.
How it got into the pond is unknown. Our neighbours did have carp in a tank which they transferred to their pond, which connects with ours, so that is a possibility.
It was time to take on the tall grass of the meadow. The primrose, cowslips, fritillaries and pyramid orchids were all gone – the cow parsley and other umbellifers were setting seed. So out came the scythe and the whet-stone and back came the memory of the steady stance, the slow swing and the regular sharpening routine I learned some years ago at one of Simon Fairley’s classes.
Inspired by Painting the Modern Garden, the exhibition at the Royal Academy earlier this year, the gift of a book on iris from a friend on my birthday, and some wonderful flowers in Tuscany, I decided to make an iris bed between the greengage trees in the glade beside the meadow.
The bed gets plenty of sun from early morning to mid-afternoon. Digging it out and removing roots of perennial weeds took ages but the hard work was interspersed with dipping into books and catalogues to decide what to plant and where to go for them. Woottens of Wenhaston provided Jane Phillips, Souvenir de Mme Gaudichan and iris germanica. Peter Beales Roses had a lovely dwarf bearded iris called Hocus Pocus and in Diss I found four pots of an iris germanica named Black Stallion. I plan to plant iris reticulata in amongst these to get some early blooms.
After a year with hardly any duckweed (don’t ask me why) it’s back with a vengeance.
There are 8 ducks apparently hoovering it up for hours every day, but neither they nor the grass carp, which also feed on duckweed, make much difference when there’s this much on the pond. In the right conditions, according to the books, duckweed can double in 3 days.
We clear it by the very simple method of putting on waders, getting into the pond, and pushing a long 6 inch plank held on edge through the water, so the weed piles up in front of it. Enough of the plank is submerged to trap the weed in large quantities.
We push it to the bank and then scoop the thick accumulation of duckweed out with a grass rake, onto a large plastic sheet, allowing the water to drain back into the pond along with lots of tiny creatures. The plan is to reduce the duckweed to the point at which the ducks and fish can eat all the new growth andkeep it under control.
And here is the cleared pond. The green in the centre is the reflection of a bush in the clear water!
Lots of people say blanket and duck weed should be put on the compost heap. Just turned over a year old, well looked after heap, which has been banked up with earth and has plenty of soft material in it, so ideal composting conditions. We discovered none of the pond weeds had rotted. Not such a good idea after all.
However, we’ve increasingly used the pond weeds as mulches to keep the roots of plants damp and to wipe out weeds, and especially the reeds that are trying to conquer the edges of the pond again. So the pond is producing a useful product after all.
Last year’s big effort to clear blanket weed by physically removing it has paid off, so far. It has been surfacing again in clumps this spring but not nearly as much, so an hour’s work in waders was enough to clear it. Every bit that comes out removes nutrient from the pond, because – looking on the bright side – you could regard blanketweed growth and removal as a way of sucking up excess nitrates and phosphates and putting the pond in better balance. There is still plenty of it close to the bottom but I suspect that the combined effect of the clouds of daphnaea and the three grass carp – all algae eaters – may be keeping it under control.
Since this is the breeding season for many creatures we pulled the weed out in small clumps and then laid it by the water’s edge so they could escape. We seem to have large numbers of common newts, more than we have seen before, and we made sure they didn’t get trapped. They obviously like it here.
Only very small quantities of duckweed so far.
Sad that a hedgehog is now a sight rare enough to cause excitement – here’s the first we’ve seen in the garden.
Good to see the Kingfishers returning, and the spotted flycatchers are nesting in an alcove by the back door. Three chicks this year.