Switchgrass, a native plant species, grows from late spring to early fall and becomes dormant during the colder months; it is abundant throughout the United States east of the Rocky Mountains and into Canada. Bay grasses, or submerged aquatic vegetation, live underwater throughout the Chesapeake Bay Watershed and are important because they help improve water quality and stabilize bottom sediment. Monarch butterflies, recognizable by their orange color, are born in Florida, Texas, or Mexico, migrate north during the spring, and then migrate south for the winter. Invasive species are non-native plants introduced into the environment that harm wetlands by overcoming native plants and changing the structure of the food cycle, and phragmites grass is one such invasive species. Travel to Chesapeake Beach also included the Chesapeake Beach Railway, whose route from Washington, D.C., to Chesapeake Beach was slightly more than 28 miles; local trains stopping at all stations took about 90 minutes, weekend express trains made the trip in about an hour, and regularly scheduled steamships brought visitors from Baltimore, although proposed steamship connections with the Eastern Shore were never realized.