All right, sounds good. When you add plants it will probably be best to put them in pots; the gravel will not be a good rooting medium until the filter's been running a while and has plenty of organic muck in it.
Some native plants I would look at:
submersed plants:
fanwort (Cabomba caroliniana)
coontail (Ceratophyllum demersum)
elodea (Elodea canadensis)
- all familiar aquarium plants
floating-leaved plants:
American white water lily (Nymphaea odorata) - classic water lily, large fragrant flowers
spatterdock (Nuphar advena) - smaller, with yellow flowers
pondweed (Potamogeton species) - submerged and floating leaves, small club-like flowers
marsh pennywort (Hydrocotyle species) - small round leaves, small yellow flowers
emergents with broad leaves:
water primroses (Ludwigia species) - low vegetation, pretty yellow flowers, 6-12"
water willow (Justicia americana) - small leaves, purple or white flowers, 12-24"
pickerelweed (Pontederia cordata) - large leaves, pretty purple flower spikes, 24-30"
golden club (Orontium aquaticum) - large leaves, golden club-like flower
cardinal flower (Lobelia cardinalis) - pretty red flowers, 30-36"
lobelia (Lobelia species) - pretty blue flowers, 18-36"
arrowhead (Sagittaria species) - arrow- or spear-shaped leaves, white flowers, 12-30"
green arrow arum (Peltandra virginica) - large arrow-shaped leaves, 18-24"
knotweed (Polgonum species) - form dense stands, small white or pink flower spikes, 12-30"
swamp dock (Rumex verticillatus) - reddish stems, large leaves, 24-36"
water plantain (Alisma subcordata) - large leaves, small flowers, 18-24"
rose mallow (Hibiscus laevis, H. moscheutos) - interesting leaves, enormous white or pink flowers, 30-48"
swamp loosestrife (Decodon verticillatus) - pretty purple flowers, 18-30"
grassy emergents:
horsetail (Equisetum hyemale) - tall dark jointed stems, 24-48"
burr reed (Sparganium americanum) - strap-like leaves, spiky flowerhead, 24-30"
swamp iris (Iris species) - sword-like leaves, large attractive flowers, 12-36"
sedges (Carex species), flat sedges (Cyperus species), rushes (Juncus species), spikerushes (Eleocharis species) - grassy foliage, often interesting flowerhead or fruit shapes, very diverse, 6-36"
There are many many others, but this should get you started! If you have some shallow marginal areas you can also grow smaller species like marsh marigolds, buttercups, mud plantains, and so on.
Some native plants I would look at:
submersed plants:
fanwort (Cabomba caroliniana)
coontail (Ceratophyllum demersum)
elodea (Elodea canadensis)
- all familiar aquarium plants
floating-leaved plants:
American white water lily (Nymphaea odorata) - classic water lily, large fragrant flowers
spatterdock (Nuphar advena) - smaller, with yellow flowers
pondweed (Potamogeton species) - submerged and floating leaves, small club-like flowers
marsh pennywort (Hydrocotyle species) - small round leaves, small yellow flowers
emergents with broad leaves:
water primroses (Ludwigia species) - low vegetation, pretty yellow flowers, 6-12"
water willow (Justicia americana) - small leaves, purple or white flowers, 12-24"
pickerelweed (Pontederia cordata) - large leaves, pretty purple flower spikes, 24-30"
golden club (Orontium aquaticum) - large leaves, golden club-like flower
cardinal flower (Lobelia cardinalis) - pretty red flowers, 30-36"
lobelia (Lobelia species) - pretty blue flowers, 18-36"
arrowhead (Sagittaria species) - arrow- or spear-shaped leaves, white flowers, 12-30"
green arrow arum (Peltandra virginica) - large arrow-shaped leaves, 18-24"
knotweed (Polgonum species) - form dense stands, small white or pink flower spikes, 12-30"
swamp dock (Rumex verticillatus) - reddish stems, large leaves, 24-36"
water plantain (Alisma subcordata) - large leaves, small flowers, 18-24"
rose mallow (Hibiscus laevis, H. moscheutos) - interesting leaves, enormous white or pink flowers, 30-48"
swamp loosestrife (Decodon verticillatus) - pretty purple flowers, 18-30"
grassy emergents:
horsetail (Equisetum hyemale) - tall dark jointed stems, 24-48"
burr reed (Sparganium americanum) - strap-like leaves, spiky flowerhead, 24-30"
swamp iris (Iris species) - sword-like leaves, large attractive flowers, 12-36"
sedges (Carex species), flat sedges (Cyperus species), rushes (Juncus species), spikerushes (Eleocharis species) - grassy foliage, often interesting flowerhead or fruit shapes, very diverse, 6-36"
There are many many others, but this should get you started! If you have some shallow marginal areas you can also grow smaller species like marsh marigolds, buttercups, mud plantains, and so on.
.