Native to ponds and marshes of colder or temperate climates, simplestem bur-reed enjoys growing in rich, wet soil. Bur-reed thrives in full sun with some tolerance for shade and prefers muddy or shallow waters,. Found scattered throughout the United States, it can be considered to be weedy or invasive for humans; however, wildlife find it quite useful as a food source and incorporate the leaves into lodging and nests. There are many varieties of bur-reed, and the simplestem is also known as exotic bur-reed.
Prepare a level surface to grow your seedlings on inside a greenhouse or indoors with good lighting and air circulation. Double-check your plastic tray for any holes to be certain it can hold water for a long period of time.
Fill as many pots as needed with soil and place into the plastic tub. Fill the tub with 1 to 1 1/2 inches of water.
Set your seeds into the center of the pots and cover with 1/4 inch of soil. Be sure the tub remains full with standing water to keep the soil thoroughly moist. Marking your water line on the tray may help you keep the water ad a consistent level.
Add more depth to the water as the plants grow. Typically, adding 1/2 inch more water every week or two is sufficient to keep up with the saturation needs of the growing plants.
Take your seedlings and tray outside to a cold frame to let them continue to establish over the spring. If your seedlings have turned into established plants by the time spring comes then feel free to go ahead and plant them out in their permanent spots after a week or two of hardening off.
Plant the bur-reed out to its permanent spot along a pond, swamp or marsh in the summertime. Space multiple plants out to give full coverage of an area or group them together to create a visual barrier in clumps around the edge of the water.