Bearing in mind the size of the pond, modest size, easy to control, robust enough to cope with hot summers would be a useful set of priorities, plants which when they settle in will help moderate water temperatures through the season
Surface coverage:
Water hyacinth, fast foliage early in the season, easy to pitch when it masses up
Eyecatching specimen plant:
Small tropical waterlily e.g. Tina, Islamorada, Madame Ganna Walska
Petite tall heat tolerant plants:
Any of Japanese rush, Pickerel, Cyperus isocladus, Umbrella palm
Those three 'types' of plants will get along fairly easy to control, the trop lily over one side where you can keep it from being entangled and crowded, the hyacinth where it can mass up, the tallish plant tough enough to cope with wherever it is best used.
Groups of three or five complimentary plants as a group tends to have a natural symmetry
Allowing a space for open water, sufficient to see into the deep part of the pond is useful, to notice how stable the water quality is. Things can go wrong fast, out of sight...
Anything else might be chosen for eye candy, predator cover... or nibblies for the fish
Regards, andy
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