Hostas Require Extra Attention in Autumn—Steps You Should Take Now for Thriving Plants

Barbara Gillette is an accomplished Master Gardener, herbalist, beekeeper, and journalist with three decades of expertise in cultivating and propagating a variety of fruits, vegetables, herbs, and ornamental plants.

Hostas are typically low-maintenance plants that enhance the texture and vibrancy of shaded gardens. However, taking a few additional precautions in the fall can significantly impact their chances of surviving the winter.

As the temperatures at night begin to approach the freezing point and the trees shed their foliage, it’s the moment to get ready and safeguard your hostas against the winter elements.

Ranging from tiny dwarf types to those reaching heights of 4 feet, these cherished leafy plants begin to wither and decline.

Caring for Hostas During Autumn

Hosts flourish in USDA hardiness zones ranging from 3 to 9. The foliage emerges from a crown and withers in the winter months, while the crown and root system remain perennial, entering a dormant phase as the days shorten and temperatures fall below 40°F.

It’s essential to recognize that these plants need a chilling phase of at least 30 days, varying by variety, to produce fresh leaves in the spring.

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Pruning

During the autumn season, many gardeners choose to clear away dead leaves. As the foliage transitions to yellow and then brown, it eventually falls off the plant on its own after it has completely withered. You can typically pull off the withered leaves, or, for larger, denser plants, it’s advisable to trim the foliage back in early winter. Use gardening shears to remove any fresh leaves, ensuring that you do not harm the plant’s crown in the process.

To protect your plants during the winter, you can use spent leaves to cover the crown, but the most effective method for safeguarding against overwintering insects, pests, and diseases is to remove and dispose of the leaves.

Dividing

Hostas are typically divided during the spring season, although they can also be divided in the fall. In northern regions, it’s best to separate the plants in September, while in southern areas, October is the ideal time.

If you complete this task at least 30 days prior to the initial frost in your region, you can move the divisions to a new outdoor site. However, if you miss this window, you can place the divisions in pots to keep them indoors over the winter, and then transfer them outside after the frost in the spring.

Mulching

In the middle to late November, apply a layer of pine needles or straw over the entire plant to shield the crown and root system from the freezing and thawing conditions of winter.

Applying mulch helps to prevent soil heaving, inhibits weed growth, and helps to keep soil moisture intact. It is advisable to take away the mulch in early spring as new growth starts to appear.

Pests

Hostas are susceptible to various harmful pests that can mar the beauty of your plants, harm their roots, and potentially lead to their complete destruction.

Slugs and snails munch on leaves, creating holes and leaving behind shiny, silvery trails. Nematodes, on the other hand, consume the foliage, resulting in yellowing and brown streaks. Voles, which are rodent nuisances, enjoy the tender roots of your hosta plants.

Clearing away fallen leaves in the fall eliminates the food supply for nematodes and mollusks. Although slugs are typically more common in the spring, they can survive the winter hidden beneath decomposing leaves and wood.

Voles utilize fallen leaves as a winter refuge and an ideal spot to conceal themselves while reaching the abundant root network.

In the fall, ensure that the space surrounding your hostas is clear of fallen leaves from trees, and once the hosta leaves have been cleared, apply a layer of mulch to protect the plants. To manage voles, consider using traps or repellents.

Watering

Once the leaves of hostas have withered, they won’t need much watering; however, it’s essential to safeguard the root system during the freeze/thaw periods, and watering is an effective method to achieve this.

The need for watering varies based on your climate; in regions with mild and rainy winters, you might not need to water your plants at all.

No matter your location, ensure that you thoroughly water hostas every one to two weeks during the fall season, continuing until the first frost occurs. It’s best to water them at the soil level in the morning.

Wintering Hostas in Containers

Hostas that are grown in containers tend to go dormant slightly sooner than those cultivated in gardens. When temperatures fall below 40°F, the preferred method for overwintering potted hostas is to relocate them to an unheated garage or shed.

If an indoor space is not accessible, relocate the containers to a protected spot and shield them with plastic tarps or dried foliage.

Maintain a relatively dry environment for the plants and only water them sparingly if the temperatures stay above 50 degrees Fahrenheit for a few consecutive days.

Safeguard ornamental planters.

Place hostas in nursery containers and position them within ornamental ceramic pots. This approach allows for easier relocation to a sheltered area and helps prevent the risk of cracking and harm to costly decorative pots subjected to winter conditions.

Fall Care Guidelines for Hostas

• Stop applying fertilizer after late summer to minimize new growth that could be susceptible to winter harm.
• At the end of the season, trim away the faded leaves and shorten any fresh growth back to the base.
• Ensure that plants are clear of any fallen leaves and debris until the arrival of the first frost.
• Once the first frost occurs or is imminent, thoroughly cover the plants with a blanket of straw or pine needles.
• Maintain a regular watering schedule until frost arrives, then reduce watering to a minimum, just enough to keep the root area damp.

Should hostas be trimmed in the autumn?

Clearing away old leaves and trimming your hostas can help avert possible issues. Fresh growth can be vulnerable to harm from freezing temperatures in winter. Additionally, remnants of old foliage can provide a cozy refuge for pests such as slugs and voles.

Is it advisable to divide hostas during the autumn season?

Dividing hostas in the fall is perfectly acceptable, especially if the plants have become too large for their allocated spaces. However, the majority of gardeners prefer to separate hostas in the spring, as new growth starts to emerge.

Is it advisable to cut over hostas during the autumn season?

Cutting grass around hostas can harm the plant’s crown or the buds that are near the ground. If you don’t have to trim a large area, it’s better to use a hand tool for the job.