Perennial ornamental grasses are often used for landscaping. They are used to designate a tall border, when planted in long rows, or as a specimen plant when planted in groups or as a single plant. Perennial clumping ornamental grass varieties that grow tall and wide, such as pampas grass and miscanthus, die back in cooler climates, leaving large amounts of dead foliage that some may consider unsightly. In most cases, dead foliage on ornamental grasses can be cut back to 6 inches from the ground in early spring. Other times, the foliage can be burned to rejuvenate the plant for spring growth.
Contact your local fire department to find out if there are any rules or regulations concerning outdoor burning. Also, let your neighbors know what your plans are so they can protect their personal property, especially if the ornamental grasses are located close to their property line.
Choose a calm day for the controlled burn of the foliage of the ornamental grass in early spring just before new growth appears. This time period allows the grass to recover quickly from the burn. Removing or burning the foliage in the fall is not recommended because the dead foliage is used by the plant to insulate the root crown from freezing temperatures.
Cut off any seed heads or plumes still attached to the ornamental grass you are burning with a handheld pruning device. The plumes are very flammable and the cinders from the burning plumes can travel a long distance. A pair of leather work gloves will prevent your hands from being damaged by the sharp leaves characteristic of many ornamental grasses.
Spray water on the ground and surrounding plants to a distance of 15 to 20 feet around the ornamental grass you are burning. Be aware of any structures, containers, fences, dry wood and other flammable objects in your landscape, or your neighbors', that might be affected by a large fire. A fire from a mature pampas grass plant can reach 20 feet high in a matter of seconds, so be prepared. Miscanthus is known for its ability to put out immense heat from its burning leaves.
Set the foliage on fire at the base of the plant while the water hose with the water source is in close proximity. Do not use any fire propellant such as gasoline or lighter fluid. Not only is it dangerous, it will cause the flames to build very quickly. The ornamental grass will completely burn to the root crown within 20 minutes. Don't allow the burned material to smolder in the root crown or the root crown may be damaged. Soak the root crown with water and rake away any smoldering debris, soaking it with water. Monitor the burn area for 24 hours to be sure the fire is completely out.