The return of a hanging fern each year depends entirely on its specific type and your local winter climate. Most lush, dramatic hanging ferns purchased for patios are tropical varieties, such as Boston and Macho ferns. These plants cannot survive freezing temperatures and will not naturally return if left outdoors. They are grown for their attractive foliage during the warm season but require intervention to persist through cold months.
Understanding Fern Hardiness and Climate Zones
Ferns are categorized into two groups based on cold tolerance: hardy and tropical. Hardy ferns, such as the Ostrich or Christmas fern, are perennial plants whose underground rhizomes withstand ground freezing and reliably re-emerge in spring. Tropical ferns are tender plants originating from warm, humid climates. They suffer irreparable damage or death when temperatures drop below approximately 50°F.
A fern’s ability to survive outdoors is determined by the local USDA Hardiness Zone. If your region experiences frost or prolonged periods below freezing, tropical varieties must be treated as seasonal annuals or moved indoors. For example, a Boston fern (Nephrolepis exaltata) only survives year-round in the warmest zones, typically Zone 9 or higher, where frost is rare.
Strategies for Indoor Overwintering
To ensure your tropical hanging fern returns, bring it inside before the first frost, ideally when nighttime temperatures consistently fall below 50°F. Before relocation, thoroughly inspect the plant for pests like spider mites or aphids. Hose down the fronds to wash away any hitchhiking insects, and lightly prune back any straggly or damaged fronds to make the plant more manageable.
Once inside, the fern should be placed in a bright area that receives indirect light, such as a window facing east or west. Direct, intense sunlight can scorch the delicate fronds, while a location that is too dark will cause excessive leaf drop. The ideal indoor temperature range is cool but consistent, generally between 60°F and 75°F, avoiding placement near cold drafts or hot air vents.
Managing humidity is a challenge during winter, as indoor heating systems dry the air significantly. Increase localized humidity by grouping plants together or by placing the pot on a saucer filled with pebbles and water, ensuring the pot bottom does not sit in the water. Since the fern’s growth slows during this semi-dormant period, reduce watering to only when the top inch of soil feels dry. Fertilization should be suspended entirely.
Reviving Dormant Ferns for Spring Growth
The transition from a cooler indoor winter environment back to active growth requires a specific process to avoid shocking the plant. In late winter or early spring, you may notice significant browning or dieback of the fronds, which is a normal response to indoor wintering stress. The plant benefits from a hard prune at this point, cutting back all the old, brown foliage down to just a few inches above the soil line.
This drastic pruning encourages the plant to produce new, fresh fronds when conditions improve. After pruning, the fern can be repotted into a slightly larger container. Alternatively, refresh its soil by gently scraping away the top layer and replacing it with new, moist potting mix. Begin increasing water frequency and resume monthly feeding with a diluted, all-purpose fertilizer to encourage new growth.
Before permanently moving the fern outdoors, it must be hardened off to acclimate it to the sun and wind. Start by placing the fern in a shady, protected spot outdoors for a few hours each day. Gradually increase the duration and exposure over one to two weeks. This slow introduction prevents leaf burn and ensures the plant is ready to thrive for the entire warm season.