There's a difference between groups of plants and how/where they grow:

Aquatic and semi-aquatic plants grow in the water, with most or all of the plant submerged most or all of the time, particularly the root structure. These include water lilies, lotuses, millefoils, and others.

Wetland plants grow in areas that are soggy most or all of the year. Their roots are adapted to uptake nutrients even in the presence of very very low oxygen (anaerobic conditions), and some are even further adapted to live in conditions of low pH (peat bogs), high salinity(estuaries), or soils that are so loose that large plants would not stand up to winds or storm action (cypress or mangrove swamps). Some examples include cattails, rushes, cranberries, Siberian irises, purple loosestrife, high-bush wild blueberries, and hemlock, willow, and sycamore trees, which like very moist soil but are perfectly happy if it gets drier for a few weeks out of the year.

Cannabis is an upland plant that can only grow where the soil conditions are aerobic. The only way to get it to grow hydroponically is to provide SIGNIFICANT levels of dissolved O2 in the nutrient solution. Plus you have to regulate the nutrients- impossible in a river.