Four or five grass carp (amur) are pretty hard on lilies in a pond less than 1 acre. In ponds where lilies are well established in big (20-40 ft) patches, damage from a few grass carp is not really noticable. But, Hybrid Lilies are very hard to get established in a pond less than 1 acre with grass carp already present. G.carp tend to eat the new sprouts and pull out freshly planted lilies and make "short work" of small thin, lily patches. G.carp like to eat new lily leaf growth in the spring when not much else besides filamentous algae is growing.
If a pond has other more palatable plants present for g.carp to eat, then lily establishment may not be as great of a problem. Many ponds with g.carp have most of the good tasting plants already eliminated by the amur. Some have given up trying to grow lilies in a 1/3 ad pond with two large grass carp present. They are now trying to get the g.carp out; not such an easy task as they initially thought.
For getting lilies established with Amur present
one would initially think of fencing off the lilies. I have tried putting tree branches around the new lily growth with some success.
Once grass carp discover the lily flowers, I found that amur will quickly eat the fresh lily flowers so if you have grass carp and water lilies expect to see fewer flowers and the flowers will not last as long compared to when amur are absent.
Andy - Hybrid Lilies are doing pretty good. Doing well are Fire Opal, Lily Pons, Peter Slocum, Carolina Sunset, Peaches and Cream, Gold Metal, Joey Tomochick, Perry's Double White. Growing but, I still don't have good growth for some of the less aggressive lilies such as Atropurpurea, Wildfire, Vivid Rose, Mayla, Almost Black and Chrometella. Just getting established Venus and Indiana, Did not have much luck with James Brydon, Are-En-Ciel, Pink Heaven, Perry's Baby Red, Hollandia.
