Ferns can quickly become a significant problem in a garden or landscape, often aggressively outcompeting desired plants. Many species possess a remarkable resilience that allows them to colonize areas rapidly. Effective removal requires a targeted approach that addresses the plant’s unique biology, as general weeding often proves unsuccessful. This guide explores the most effective methods for eliminating unwanted ferns, from manual labor to chemical application.
Understanding Fern Growth Patterns
Ferns are challenging to eliminate because of their specialized reproductive and growth structures. Most species spread aggressively through underground stems known as rhizomes, which can extend horizontally through the soil. If even a small fragment of a rhizome is left behind after removal, it contains enough stored energy to sprout new fronds and re-establish the plant.
The plant’s primary method of reproduction is spores. These microscopic, dust-like particles are produced on the underside of mature fronds and are easily dispersed by wind, allowing ferns to colonize new areas. This dual strategy of rhizome expansion and wind-borne spore dispersal makes ferns difficult to eradicate. Successful removal must address both the established underground network and the potential for new growth from spores.
Manual and Cultural Removal Methods
The most direct way to eliminate ferns without chemicals is through physical removal, which requires meticulous attention to the underground structures. When digging, use a garden fork or shovel to carefully lift the entire clump, ensuring that every piece of the rhizome system is extracted. Simply pulling the fronds above ground leaves the energy-storing rhizomes intact, leading to immediate regrowth.
For widespread infestations, smothering (occultation) is an effective long-term strategy that starves the plants of light. The area should be covered with thick black plastic, multiple layers of cardboard, or heavy mulch, which completely blocks the sunlight needed for photosynthesis. This method works slowly over several months, forcing the underground rhizomes to deplete their energy reserves until they die.
Modifying the environment can make an area less hospitable to fern growth, a form of cultural control. Ferns typically thrive in shaded, moist environments, so reducing irrigation deters their establishment. Maintaining a dense ground cover of desirable, more competitive plants can also prevent airborne spores from settling in bare soil. Repeatedly cutting the fronds back throughout the growing season will deplete the rhizomes’ energy, weakening the plant.
Chemical Control Options
Chemical control is often necessary for large, deeply established fern colonies that resist manual removal. Contact herbicides that only burn the leaves are generally ineffective and result in rapid re-sprouting from the rhizomes. The most successful approach involves using a systemic herbicide, such as one containing glyphosate, which is absorbed by the foliage and translocated down to the rhizomes.
Targeted application is crucial for the chemical to reach the entire plant, especially the aggressive underground stems. One effective technique is to cut the fronds down to a short stump and immediately apply the concentrated herbicide directly to the fresh cut. Applying the chemical to new, tender regrowth, rather than older, waxy fronds, increases the rate of absorption and translocation to the rhizomes.
The most effective time for application is when the fern is actively growing, typically in mid-to-late summer. During this time, the plant is transporting nutrients down to its root system for winter storage. Applying the herbicide during this phase ensures the chemical is carried along the plant’s natural transport pathways to the rhizomes. Always follow label directions for personal safety, including wearing gloves and eye protection, and prevent the non-selective chemical from drifting onto desirable plants.