Maiden grass (Miscanthus) is a total favorite for adding texture to the garden, but keep in mind that it spreads via rhizomes. While it doesn’t take over quite as aggressively as some other ornamental grasses, you’ll definitely thank yourself later if you install a root barrier when planting it in the ground.
Annual Growth
How much your maiden grass spreads underground each year depends on a few things, like where it’s planted and the quality of your soil. Your maintenance routine plays a role, too—pruning it back regularly can actually help keep that outward spread in check.
The specific variety you choose also makes a difference in speed. It’s pretty common to see the rhizomes push out several inches a year. However, compared to other spreading ornamental grasses, maiden grass is actually on the slower side when it comes to annual growth.
Choosing the Right Material
You’ll find a few different options for root barriers at the garden center. Since maiden grass has pretty tough rhizomes, I recommend using high-density polyethylene (HDPE). This is the same heavy-duty stuff people use to contain bamboo.
Some gardeners try to save a few bucks by burying plastic mortar tubs or old planters in the ground. While that *can* work to stop the roots, those containers often trap too much water, leading to root rot. If you want to grow your grass in a pot, it’s usually better to keep it as a container plant on your patio or balcony rather than burying the pot.
How to Install the Barrier
When you’re ready to plant, dig a hole that’s slightly wider than usual. Place your root barrier into the hole, leaving a bit of space between the barrier and the walls of the pit. Fill that outer gap with some gravel for drainage, and then top off the last few inches with soil.
Finally, set your maiden grass right in the center of the barrier. Try to make sure it’s centered perfectly so the plant grows evenly in all directions. This is especially important if you’re using the grass as a focal point or “specimen plant” in your landscape—you want it looking symmetrical and beautiful from every angle!
