Growing Hostas: Wintering Over

Part of successfully growing hostas is arranging for them to have a period of rest and regeneration at the end of each growing season. Wintering-over hostas isn't a difficult process, but it is an important one.

Hostas get their cue to enter a dormant state in the fall, but it's the change in the length of daylight rather than change in temperature that gives them the signal. Whether your area is warm or cool, your hostas will start to die back in the autumn. This is crucial for the plants, which cannot do without a dormant period.

Gradually cut back on watering and stop fertilizing all together when the plant starts to die back in the fall. It's a good idea to trim away dead leaves, which lessens the possibility of bacterial problems.

If your hostas are planted in the ground, wintering over is a simple matter of making sure all dead leaves have been trimmed away, then adding a couple of inches of mulch to cover.

If you're growing hostas in pots rather than in the ground, wintering over is a bit more complicated. The right kind of soil is important; soil that holds too much moisture can create root rot during the dormant period, but potted hostas do need some moisture to get them through the winter. Keep watering lightly as the plant dies back.

There are several ways that potted hosteas can be wintered over. One solution is to trim back all dead growth, then put the pots into a hole or trench large enough to bring the top of the container to ground level or a few inches above ground level. Cover the top of the pots with a commercially-available insulating blanket, then top with a piece of plywood to keep out excess moisture and small scavengers like mice and voles.

If that's not feasible, try digging a shallow trench that will permit you to tip the pots on their sides (important to prevent excess water from pooling, seeping into the soil, and eventually rotting the roots). Cover with an insulating blanket or pine brush, but don't use black plastic (like garbage bags), which would trap too much warmth and could cause early thawing.

You can also winter-over potted hostas by keeping them in a cool, dry, dark place (like a basement, garage, or crawl space). Cover the tops of the pots with weighted-down plywood for mouseproofing, but make sure you can remove the cover because about half way through the winter you need to check for moisture. If the soil feels very dry, add some water so the roots stay moist.

In the spring, move plants outside or uncover before the spring thaw is complete but be prepared to recover plants if the weather reverts to freezing.

Hostas are the number one perennials in US gardens, and no wonder - they're adaptable, easy-to-grow plants that need little care but provide a beautiful display. To learn more about growing hostas, visit the Growing Hostas website.