Why grasses work in pots
Grasses give containers height, movement and fine texture. In the classic combination, a grass serves as the “thriller” (the tall focal plant), with flowers as fillers and trailing plants as spillers. Many grasses also handle sun and drying wind better than flowering annuals. If you are still deciding, see do ornamental grasses do well in pots?
Choosing a container
- Size: choose a pot at least as wide as the grass’s nursery container plus a few inches, and larger for tall or fast-growing types. A bigger pot holds moisture longer and gives roots more room.
- Drainage: drainage holes are essential. Standing water around the roots can cause rot.
- Material: terracotta dries quickly; glazed ceramic and plastic hold moisture longer. Thin or small pots heat up and dry out faster.
- Weight: large containers are hard to move once planted, so position them first.
Best grasses for sunny containers
- Dwarf fountain grass (Pennisetum ‘Hameln’): a compact, arching grass for sun. See small ornamental grasses.
- Purple fountain grass (Pennisetum setaceum ‘Rubrum’): often grown as an annual in colder areas as it is not hardy there.
- Blue fescue and blue oat grass: neat blue mounds for sun and good drainage.
- Feather reed grass or compact Miscanthus: for large pots that can handle taller plants. More options are in good tall grasses for pots.
Shade container options
For shade, look at sedges (Carex), Hakone grass and mondo grass. Variegated or chartreuse forms brighten dim corners. Shade containers usually need less frequent watering than sunny ones, but check the soil rather than watering on a fixed schedule. More ideas appear in good ornamental grasses that grow in shade.
Planting and potting mix
Use a quality potting mix, not garden soil, which can compact and drain poorly in a pot. Plant at the same depth as in the nursery container. Mulch lightly with fine bark or gravel to reduce evaporation. If you want a mixed planter, combine plants with similar light and water needs.
Watering and feeding
Containers dry out faster than beds, especially in summer wind and sun. Water when the top inch or two of mix feels dry, and water until it drains from the bottom. Grasses generally do not need heavy feeding. A light application of slow-release fertilizer in spring is usually enough (see should you fertilize ornamental grasses?).
Winter care
Roots in pots are more exposed to freezing temperatures than those in the ground, so plants rated for a given zone may be less reliable in a pot. In cold climates, options include moving containers to a sheltered, unheated spot, grouping pots against a wall, or choosing grasses hardy two zones colder than your own. Keep the mix from becoming waterlogged over winter. More detail is in overwintering ornamental grasses in the ground and in pots. Cut deciduous grasses back in late winter or early spring.
Dividing and repotting
When the center of a clump thins or the roots fill the pot, divide in spring, or move up to a larger container. Discard the dead center and replant healthy outer sections.