Hostas are a very forgiving plant but hostas in pots do need some care over the winter. Hostas need a six-week period of temperatures below 40 degrees for their winter sleep. But since during this time the potted hostas can be exposed to several freezes and thaws, they need extra care to prevent damage to their roots.
Here are some tips on getting your hostas in pots to survive the cold winters.
As a general rule, your growing zone and the species of hosta you have are factors to consider. Hostas with plantaginea and lancifolia lineage are more sensitive to the cold.
A little bit about microclimates. In every garden, there are warm and cold spots, spaces where the wind flows through and areas that are more protected from the wind.
Years ago, I learned a valuable lesson about this. I had three large mature Guacamole hostas like the one above in big beautiful red plastic pots that I confidently left outdoors for the winter several years in a row.
Well, one year I moved the three pots (for whatever reason) next to the shed for the winter. Well, winter water drained right off the shred and down into those pots for the entire winter season rotting the roots. Lesson learned.
Hostas in Smaller Containers
Blue Mouse Ear Hosta in Hypertufa Container
Here's some options for making sure they make it through the winter months.
- Move the small pots to an unheated garage, shed or greenhouse for winter protection.
- Here in Zone 6, our younger hostas are overwintered in an unheated greenhouse. We check them weekly before the first frost hits to be sure the soil doesn't completely dry out. Once the hard freeze hits, the hostas are left on their own until it begins to warm up in March.
- If you have a lot of small pots, you can bury the entire group in the ground, or huddle them together out of direct sun and cover with leaves. If you do bury your pots, make sure you uncover them before the leaves unfurl in the spring. If a late frost threatens, recover them to prevent late frost bite.
- Another option is to place the pots on their sides once the freeze hits. This will protect them from excessive rainfall which can rot the roots.
Hostas in Large Containers
The Shining Hosta
Large potted hostas will normally overwinter well. The above large The Shining hosta is planted in a plastic red pot. Here is Zone 6, it survives the winter without being taken into an unheated shed, garage or greenhouse. To help ensure it survives the winter:
- Adding a two to three-inch layer of mulch will help. Be careful, though, not to smother the roots with too much mulch. The roots need some airflow. Leaves and straw are two of the best mulches to use as they're lighter and provide air pockets.
- If you have a prized hosta that you don’t want to take chances with, you can always bury it half way or fully in the ground for the winter, and repot in the spring.
And remember, snow is a great insulator!
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