The foxtail fern (Asparagus densiflorus ‘Meyeri’) is a popular ornamental plant known for its dense, plume-like fronds that resemble a fox’s tail. This perennial is technically not a true fern but a member of the asparagus family. Its survival during the winter months depends entirely on the local climate and specific care provided. Gardeners in mild regions can often keep the plant outdoors year-round, while those in colder areas must take protective measures to ensure it survives the winter season. Understanding the plant’s natural limitations is the first step in determining the proper overwintering strategy.
Cold Tolerance and Hardiness Limits
The foxtail fern is winter-hardy in United States Department of Agriculture (USDA) Hardiness Zones 9 through 11, which encompass regions with mild winters. Within these zones, the plant can tolerate brief dips in temperature, remaining evergreen in frost-free environments. Its survival limit is tied to the temperature threshold of its underground structures, which are the most resilient part of the plant.
The root system, which includes thick, water-storing tubers, can marginally tolerate temperatures as low as 20 to 25°F for short periods. When temperatures fall below freezing, the plant’s delicate foliage will often suffer damage and die back to the ground. As long as the roots remain viable, the plant will regenerate new fronds in the spring. Gardeners in Zone 8 are in a marginal climate where the plant may survive with protection, but colder areas require relocation indoors.
Strategies for Outdoor Winter Protection
In marginal climates like USDA Zone 8 or the cooler parts of Zone 9, a few strategies can significantly increase the foxtail fern’s chances of surviving the winter outdoors. One proactive step involves adjusting the plant’s watering schedule in the late fall to prepare it for dormancy. Reducing or ceasing watering allows the soil to dry slightly, which prevents the roots from becoming waterlogged and vulnerable to rot during cold, wet periods.
Mulching is a highly effective method for insulating the root zone of in-ground plants. Applying a thick, six-to-eight-inch layer of organic material, such as straw or shredded bark, over the crown helps to stabilize soil temperatures and protect the roots from deep freezes. This insulating layer prevents the rapid freezing and thawing of the soil, which can physically damage the root system.
For unpredictable cold snaps, temporary physical covers can provide necessary short-term protection. When freezing temperatures or frost are forecasted, covering the entire plant with a lightweight frost cloth, burlap, or an old sheet will trap heat radiating from the soil. The cover should be removed once temperatures rise above freezing to prevent excessive moisture buildup. Furthermore, placing the plant near structures, such as a south-facing wall, capitalizes on beneficial microclimates that offer extra warmth and shelter from harsh winter winds.
Bringing Foxtail Ferns Indoors
In regions colder than USDA Zone 8, the foxtail fern must be treated as a temporary houseplant to survive the winter. Before the first expected frost, thoroughly inspect the plant for pests like mealybugs or spider mites, as they can quickly spread to other indoor plants. A strong spray of water or treatment with insecticidal soap eliminates pests before the transition indoors.
Once inside, the foxtail fern requires specific conditions. It does best in a location that receives bright, indirect light, such as an east-facing window or a spot several feet from a south-facing window. Ideal indoor temperatures should remain between 60°F and 75°F, and the plant must be kept away from cold drafts or direct heat sources like radiators.
Adjustments to the care regimen accommodate the plant’s semi-dormant state. Watering should be significantly reduced, allowing the top inch or two of soil to dry completely between waterings. Fertilization should be suspended entirely during the winter, as the plant is not actively growing. Maintaining moderate humidity is beneficial, achieved through regular misting, grouping plants, or placing the pot on a pebble tray filled with water.
Identifying and Treating Cold Damage
Cold damage on a foxtail fern is usually noticeable by a change in the foliage’s appearance. Fronds hit by frost typically turn brown, yellow, or take on a mushy, water-soaked texture. This visible dieback can make the plant look completely dead above the soil line, which is a common sight after a severe freeze.
Recovery is dependent on the survival of the underground rhizomes, the root structures that store water and energy. If the roots have not frozen solid, the plant has a strong chance of recovery, even if all the foliage is gone. It is best to wait until late winter or early spring before pruning the damaged fronds.
At that time, all the dead, discolored material should be cut back down to the ground level. This pruning directs the plant’s energy toward generating new growth from the subterranean crown rather than wasting resources on damaged stems. Patience is important, as new, bright green shoots will emerge from the base once the weather warms and the plant begins its active growing cycle again.