Boston ferns (Nephrolepis exaltata) are popular ornamental plants, chosen for their lush, arching green fronds. Many people wonder about their longevity and whether these attractive plants will return year after year. Understanding the perennial nature of Boston ferns involves looking at general plant classifications and their specific environmental needs.
Understanding Perennial Plants
A perennial plant is one that lives for more than two years, distinguishing it from annuals, which complete their entire life cycle in a single growing season. Perennials often return from their rootstock after a period of dormancy, such as during cold winters.
Some perennials are classified as “tender perennials,” meaning they can live for multiple years but are not hardy enough to withstand cold winter temperatures in certain climates. These plants thrive as perennials in their native, warmer habitats but may require special care or be treated as annuals in cooler regions.
Boston Ferns and Climate Adaptability
Boston ferns are tender perennials, capable of living for many years. Their ability to return annually depends significantly on the climate. These ferns are native to tropical and subtropical regions, including parts of South America, Mexico, Florida, and the West Indies, where they naturally thrive in humid, forested environments.
They are winter hardy outdoors in USDA hardiness zones 9 through 12. In colder regions outside of these zones, where temperatures drop below freezing, Boston ferns typically do not survive the winter outdoors and are instead grown as annuals or as houseplants.
Winter Care for Boston Ferns
For those in colder climates, bringing Boston ferns indoors is necessary to ensure their survival through winter. This transfer should occur before the first frost, as these plants are sensitive to freezing temperatures. Before moving them inside, it is helpful to trim away any dead or browning fronds and rinse the plant to remove potential pests.
Once indoors, Boston ferns require specific conditions to thrive or remain dormant. They prefer bright, indirect light, with an east or north-facing window being ideal. Temperatures should ideally remain between 65°F and 75°F during the day, not dropping below 55°F at night. Humidity is especially important, as dry indoor air can cause frond tips to brown; using a humidifier, pebble tray, or regular misting can help maintain the necessary 50-80% humidity. During winter, reduce watering frequency, allowing the soil to become slightly dry between waterings, and suspend fertilization as the plant’s growth slows.
General Care for Thriving Boston Ferns
Beyond winterizing, consistent general care promotes a healthy Boston fern throughout the year. They thrive in bright, indirect light and should be protected from harsh, direct sunlight, which can scorch their delicate fronds. An east-facing window or a spot with partial shade outdoors is generally suitable.
Boston ferns require consistently moist, but not waterlogged, soil. Overwatering can lead to root rot, while allowing the soil to dry out excessively causes fronds to droop and turn brown. A well-draining, moisture-retentive potting mix, such as one with peat and vermiculite, is beneficial. High humidity levels are also crucial for their overall health; regular misting or placing the plant on a pebble tray filled with water can help meet this need. Fertilize the plant every four to six weeks during the active growing season, typically spring through fall, using a balanced liquid houseplant fertilizer at half strength.