Trouble in paradise
Last month I wrote about how much we have enjoyed our front pond in The joys of a Florida pond, but in 2011 the whole surface of the pond had become totally covered by a noxious invasive with a cute name—water spangles (Salvinia minima). It had probably come in as a hitchhiker on one of our beloved birds or traveling turtles, and from there, it went wild. My husband and I scooped out cartloads of it by dragging a 8 piece of plastic mesh between us as we walked across the pond and we scooped up more with hard plastic leaf rakes. I used it in the compost pile and as a mulch, but each time we cleared out a batch, new bright green plants filled in the spaces in a matter of days no matter how large a gap we created.
We thought a hard winter would eventually take care of it, but after two years it was still covering everything. I hated the thought of using herbicide, but there was no other solution. Bummer!
I called the contractor who had been hired to get rid of hydrilla (Hydrilla vercillata) in the big lakes in the neighborhood. He quoted us a price for treatment with Fluridone, an herbicide especially formulated for aquatic habitats. (Round-up and many other terrestrial herbicides are not effective on aquatic plants and kill the fish, turtles and other aquatic wildlife.)
He told us what other plants in addition to the salvinia the herbicide would kill. It would not affect the ferns, the irises (Iris hexagona), the rushes (Juncus effusus), hibiscus (Hibiscus coccineus), or the lizardtails (Saururus cernuus), but it would kill the native spatterdock (Nuphar advena), a large yellow waterlily that had also covered too much of the pond. It would have added a huge volume of muck in the bottom had we left it in place. Before the treatment we removed more than half of it from our side of the pond. This was a big job because of its huge rhizomes, but it does float, so after pulling it up we could herd the pulled plants to the side of the pond.
Our pond was such a small job for the contractor that he never got back to us. So after waiting 20 days, we cancelled the contract and bought the Fluridone ourselvesit was quite expensive about $140 for 8 ounces, but wed need only half of that for one treatment and our neighbors paid for half of it since they were putting their house on the market. It would be easier to sell with a clear pond.
After reading everything he could find on this herbicide, including the label, my husband put his kayak into the pond and was ready for action. He filled the 2-ml syringe ten times and injected the doses in equally spaced places just under the surface of the water around the pond. After the application, he paddled large figure 8s all over the pond to better distribute the herbicide. It would take 45 days to begin to work.
In nature, eutrophication is a part of the normal aging process of many lakes and ponds where they slowly fill up with decaying matter until they become swampy meadows or bogs. Ponds that are naturally fed rich nutrients from a stream or river or some other source are described as eutrophic, meaning they are nutrient-rich and therefore abundant in plant and animal life. In urban/suburban locations, this process is greatly sped up if peoples lawn fertilizers and debris are also carried into the ponds and lakes. Often the result of this overly nutrient-rich environment is an ugly algal slime and dead zones where fish die in the oxygen-depleted environment.
At the present time, there are no artificial nutrients washing into our pond from the surface, but there is a deep layer of muck (knee-deep in the center). Before we bought the house 10 years ago, the previous owners had hired someone to kill the pond vegetation, which probably accounts for much of the muck layer. In addition to removing the spatterdocks, we worked to reduce the amount of leaf-fall by trimming back some of the trees and shrubs at the shoreline. There is still plenty of shade, but maybe now with fewer overhanging branches, the pond muck build up will slow down some.
Now, pond life goes on
The spatterdock on the neighbors side of the pond has now completely disappeared into the water and we are enjoying the salvinia-free pond life again. We are hoping not to have to use the other half of the Fluridone for many years.
Life in the red bay snag: The beautiful red bay trees (Persea borbonia) around here were hit with the laurel wilt fungus. (For more information on red bays, see my article, Red Bay Trees are Dying.) All thats left of one of our red bays is this pond-side snag, but its covered with several species of vines including one of the Florida native passionvines (Passiflora incarnata), which is now covered with zebra longwing butterfly larvae. (See my post Teeming with Zebras.)
Have you missed the the blue mist flower (Conoclinium coelestinum), an eastern US & Canadian native? It has volunteered on the pond shoreline and the front meadow for years. The pollinators love it and so do I. There is a photo of a roadside ditch filled with blue mist flowers and black-eyed susans (Rudbeckia hirta) on the cover of my first book, Sustainable Gardening for Florida.
So I hope you are enjoying the life in and around your pond, but if you dont have one yet, maybe its time to add one to your landscape to create a better habitat for myriad wildlife species that are so much fun to watch.
Be sure to read part 1 of this adventure: The joys of a Florida pond.
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