- Joined
- Aug 10, 2017
- Messages
- 48
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- 35
- Location
- Daytona Beach, FL
- Hardiness Zone
- 13b
- Country
I live in Central Florida, a block from the ocean. A year ago I purchased two potted Canna lilies from different nurseries. I left one in the pot and submerged it in my 24" deep concrete-and-tile koi pond, placing some blocks under the pot so that the lip of it was only 1-2" below the surface. The other Canna I planted directly in the soil of my garden adjacent the pond. Both of them grew well and flowered profusely over the ensuing spring, summer and fall months. The submerged Canna in fact went nuts, with several stalks growing 6 feet high. The dry-planted Canna grew maybe 3-1/2 feet, also flowering well. As fall turned to "winter" (highs in the 60s, lows in the 50s), both plants seemed to go into latency, with browning leaves and emergence of seed pods at the tops of the stalks. Then the stalks turned brown and deteriorated, and currently this "dry" Canna appears either dead or at best, dormant. The submerged Canna continued to put out some fresh green stalks but the rest of the grown stalks developed yellow, unhealthy-looking leaves. I waded over to the pot to inspect it, and was disheartened to see the undersides of many of the leaves were coated with scale.
It occurred to me that typical sprays to combat scale are petrochemicals that I don't want in any contact with my fish. I have cut away everything but the smallest emerging Canna stalks, but my fear is that once scale is established, pruning will not eliminate it.
I have several other water/bog plants in my pond: Screw rush, alisma plantago, water lilies and water lettuce. The alisma and rush are potted on blocks just beneath the surface. The water lilies are mostly potted at the pond bottom, although the koi have sometimes pulled the lily bulbs out of their pots and then the bulbs have re-rooted in the river rocks at the bottom. They've all done fine, with healthy pads and gorgeous lilies appearing all summer long. In spring and summer, I let the water lettuce take over the main pond surface as it gives the fish some shade and also helps keep the water temperature down. None of these plants has developed anything like scale, although the alisma has occasionally gotten a pest, probably an insect larva, that chews its leaves in late summer.
Although central Florida rarely experiences freezing temperatures, there is a definite fall-off in plant activity starting in late September when daytime temperatures are still in the mid-80s, and many deciduous plants, such as crepe myrtle, begin to lose their leaves. I take all the water lettuce out of the pond then and place it in stainless steel tubs, as it stops reproducing fast enough to keep up with my kois' appetite (the koi eat the roots). Plus, the waning sunlight doesn't overheat the pond water. And it's always nice to be able to see more of the fish.
So - back to my question. How to treat scale or other water plant infestations without using petrochemicals or other solutions that are toxic to fish?
Photo: Alisma pest damage
It occurred to me that typical sprays to combat scale are petrochemicals that I don't want in any contact with my fish. I have cut away everything but the smallest emerging Canna stalks, but my fear is that once scale is established, pruning will not eliminate it.
I have several other water/bog plants in my pond: Screw rush, alisma plantago, water lilies and water lettuce. The alisma and rush are potted on blocks just beneath the surface. The water lilies are mostly potted at the pond bottom, although the koi have sometimes pulled the lily bulbs out of their pots and then the bulbs have re-rooted in the river rocks at the bottom. They've all done fine, with healthy pads and gorgeous lilies appearing all summer long. In spring and summer, I let the water lettuce take over the main pond surface as it gives the fish some shade and also helps keep the water temperature down. None of these plants has developed anything like scale, although the alisma has occasionally gotten a pest, probably an insect larva, that chews its leaves in late summer.
Although central Florida rarely experiences freezing temperatures, there is a definite fall-off in plant activity starting in late September when daytime temperatures are still in the mid-80s, and many deciduous plants, such as crepe myrtle, begin to lose their leaves. I take all the water lettuce out of the pond then and place it in stainless steel tubs, as it stops reproducing fast enough to keep up with my kois' appetite (the koi eat the roots). Plus, the waning sunlight doesn't overheat the pond water. And it's always nice to be able to see more of the fish.
So - back to my question. How to treat scale or other water plant infestations without using petrochemicals or other solutions that are toxic to fish?
Photo: Alisma pest damage
