Hostas are very popular plants for their leafy mounds and bright flowers. Not only are these plants shade tolerant, they are hardy in cold winters. Many varieties need no helpto survive the winter months in all but the most extreme environments. However, there are a few tricks to improve your hosta's chances of surviving the cold months.
Clean Up the Leaves
When hostas go dormant, the leaves die and the living portion of the plant exists only under the soil. Leaving the leaves in place can provide some weather protection to the roots but also provide a home for slugs and snails. A layer of mulch will work as well to protect the roots without attracting slugs and snails. Once the leaves die back, they can be raked away for disposal or composting. If any leaves remain you can trim them off with shears. The same is true of any remnants of the flower spikes. Trim everything as close to the crown as you can.
Destroy All Dead Leaves
Hostas suffer from a disease called Hosta Virus X, which is at epidemic levels around the world. Slow to show symptoms and always fatal in the end, this disease is transmitted when the sap of damaged plants comes in contact with healthy plants. Until this disease is controlled, all hosta growers are advised to destroy all portions of their plants that they remove and not to compost them. Additionally, during any trimming or dividing efforts, clean your tools and hands between plants to prevent any possibility of transferring the disease.
Freeze/Thaw Cycles Cause Heaving
In some areas, the winter months will alternate freezing and warmer temperatures, especially between nights and days. This can cause the roots of your hosta to be pushed up out of the ground in a process called heaving. Larger varieties can survive this process, but smaller varieties can die with their roots exposed.
To avoid heaving, you can cover the plant with mulch during the winter. This will stabilize the temperature of the soil around the roots no matter how the temperature of the air fluctuates. A layer of pine needles or straw will also work well and is less likely to provide a home for burrowing rodents or slugs. In the spring, just rake the protective layer away from the crown of the hosta to prevent rot from developing on the leaves as they emerge.
Don't Misplace Your Hostas
Hostas basically disappear into the ground during the winter and don't sprout leaves until later than many other plants. You don't want to accidentally dig up your hostas while you are prepping the soil and planting other spring flowers. Consider placing stakes near your hostas or some other marker to serve as a reminder. A pretty option is planting crocuses or some other early spring bloomer around your hostas. These will bring life to your garden as the season changes and remind you where you hostas are.