How to winterize hostas

If you're wondering how to winterize hostas, then you'll be glad to know that there aren't many steps required. While hostas aren't one of the best winter flowers to plant, they are a favorite of spring and summer gardens.

Hostas are fully hardy, so in most parts of the country, don't need any additional steps to help them survive the winter. Whether grown in the ground or as part of container garden ideas they can be left outside.

However, just as when winterizing dahlias, overwintering begonias, and winterizing hydrangeas, there are some things you can do to help your hostas get a head start in spring.

How to winterize hostas

Hostas are highly durable and are one of the best shade plants. Hostas are able to thrive in zones 3 through 8 which makes them perfect for a wide range of gardens. As herbaceous perennials hostas will die back in the fall and then re-appear the following spring. 

There are no specific steps that are needed to help your hostas survive the winter period – they can cope with frosts down to -40ºF. However, the below advice will help you to ensure that your hostas get the best start in life once spring arrives.

1. Ensure good drainage

'Hostas are more likely to die from a wet winter than a cold one,' explains experts from RHS Chelsea Gold Medal-winning hosta nursery Sienna Hostas. 

Therefore, when winterizing hostas, it is important to ensure the plant has good drainage. There are many ways to achieve this including increasing the number of plants in your flower beds, adding a bark chip mulch and incorporating organic matter like homemade compost or well-rotted manure.

2. Clear away old leaves

Hostas lose their leaves in winter, so it is good practice to clean these away before they start to decay. If left they can harbor bacteria and fungus which can damage your plant come the spring.

'Slugs and their eggs also overwinter in the shelter of the dead leaves, so by clearing them you should help reduce any slug issues in spring,' advises experts from Sienna Hostas. 'Remove the leaves also makes it easier for birds to eat any slugs or eggs that have been laid in, or around, your plants.'

3. Install slug protection

Hostas are very vulnerable to slugs and snails. Thankfully, there are lots of slug control methods that can help – one is installing a copper band around the base of the plants or adding copper coins to the surface of the soil. Doing this in winter will help to protect the vulnerable new stems and leaves from being decimated in spring. You can then apply nematodes to the soil in the spring which will further protect your hostas.

4. Apply a thin mulch

There are no downsides to applying a thin mulch to the bases of your plants in advance of winter – and the same applies to hostas. 'Because it gets really cold where I am, I tend to apply a mulch of wood bark to help insulate my plants through the coldest periods of winter,' suggests expert Alex Tinsman from How To Houseplant. 

While hostas don't need this treatment in order to make it through the winter, adding a thin mulch will help to protect the roots from extreme frosts and will provide some additional nutrients into the soil as the mulch decays. 

5. Cover if frost in spring

You do not need to cover hostas in advance of winter. Hostas can tolerate temperatures down to -40ºF. However, it is worth covering hostas if spring frosts are threatened. Once the new leaves have emerged, the plants become increasingly vulnerable as they are no longer in the dormant period. Cover hostas with fleece or cloches once the temperatures start to go down to the 20s. 

6. Protect young hostas

If you have very young hostas in pots – possibly cuttings taken in fall or those grown from seeds – then it is a good idea to protect them as they are more vulernable. 'Over a mild winter it is very unlikely that any plants would die, although if it is particularly harsh you can be left with some casualties,' says experts from Sienna Hostas.

'One of the easiest ways to protect young hostas is to put them in an unheated shed or garage in late Autumn. Hostas need temperatures of below 41°F to enter their winter dormancy which is vital to ensure vigor the following season. Alternatively, put your pots on their sides, this stops them from filling with water and freezing.'

7. Wait until spring to plant new hostas

If you are hoping to grow hostas this year, then it is best to hold off planting them until winter has passed. If planted in mid-winter your new plants will fail to thrive. Instead, spring and fall are good times to plant hostas.

Do you need to cover hostas for frost?

You only need to cover hostas for frost if it occurs once the hostas are no longer dormant. You will be able to tell if the hostas aren't dormant as they will have started to grow their new leaves. These new leaves will be extremely vulnerable to frosts so will benefit from covering. You can use frost fleece or plastic cloches – like these from Amazon – but be sure to remember to remove them once the threat of frost has passed.

Do you cut back hostas for winter?

There is no right or wrong answer to the question, should you cut back hostas in the fall? Hosta leaves die back at the end of fall and therefore, you don't need to cut back hostas for winter. However, dead or dying leaves can be cut off if desired from an aesthetic point of view - however, it will make little difference to the well-being of the plant.