Which aquatic plant typically has a height of 1-3 ft and is known for its showy violet to blue flowers?

The correct choice is Pickerelweed, which is characterized by its typical height of 1-3 feet and is well-known for its striking violet to blue flowers. This plant thrives in fresh water environments and is often found in marshes and along the edges of ponds and lakes. The showy flowers of Pickerelweed not only add aesthetic value to aquatic ecosystems but also serve as an important food source for various wildlife, including pollinators like bees and butterflies.

In contrast, the other options present distinct characteristics that do not align with the description given. Water hyacinth, for example, is generally larger, often exceeding the 3-foot height, and features large, dense clusters of lavender flowers. American frogbit is a floating plant, whose flowers are small and less showy, typically white or yellow. Southern naiad, on the other hand, is an underwater plant that does not grow above the surface and lacks showy flowers, making it visually different from Pickerelweed.