The orange daylily, Hemerocallis fulva, is a familiar sight along roadsides and in older landscapes, recognized by its vibrant, tawny-colored blooms. Despite its common usage as a hardy ornamental, this perennial species is considered an invasive plant in many regions outside of its native range in Asia. Its aggressive growth habit allows it to escape cultivation easily, forming dense patches that displace native vegetation. This guide provides effective strategies for eradicating the ditch lily from your property.
Understanding Why Ditch Lilies Resist Removal
The tenacious nature of the ditch lily stems from its specialized underground structure, which stores massive amounts of energy. Unlike many plants that rely heavily on seeds, Hemerocallis fulva spreads primarily through vegetative means. It develops thick, fleshy, tuberous roots and rhizomes that form a dense, interwoven mat just beneath the soil surface.
These tubers act as storage organs, allowing the plant to rapidly regenerate even after the foliage has been cut or damaged. If a small fragment of a rhizome or tuber is left behind, it contains enough stored energy to sprout a new plant. Therefore, any attempt at eradication must be thorough, targeting the entire subterranean network to be successful.
Manual and Cultural Eradication Methods
For smaller infestations or where chemical use is a concern, physical removal is the most direct approach to eliminate ditch lilies. Successful control demands the complete extraction of the entire root and tuber system from the soil. Use a sturdy garden fork or spade to loosen the soil widely around the clump, aiming to lift the entire root mass intact.
Carefully shake the excavated clump to remove excess soil and expose all the fleshy tubers and connecting rhizomes. Even small pieces of root material can re-sprout, so meticulous attention is required to ensure no fragments remain in the soil. Sifting through the disturbed soil by hand is often necessary to locate detached pieces.
Once physical removal is complete, cultural controls like smothering can be implemented, especially over larger areas. Begin by cutting the existing foliage down to ground level and removing the debris. Next, cover the entire area with an opaque material like thick black plastic sheeting, cardboard, or heavy mulch.
This technique, known as occultation or smothering, deprives any remaining root fragments of the sunlight necessary for photosynthesis. For effective control, the area should remain covered for at least a full growing season (six to twelve months). Alternatively, clear plastic sheeting can be used during the hottest months to solarize the soil, generating extreme heat that cooks the remaining root fragments.
Proper disposal of the removed plant material is important to prevent further spread. The fleshy roots and tubers should never be added to a home compost pile, as they will likely survive the composting process and contaminate the finished material. All excavated plant parts should be placed into durable, sealed plastic bags. These bags should be left in a sunny location for several weeks to dry out or solarize before being sent to a landfill or municipal waste facility.
Targeted Herbicide Application Strategies
Chemical control provides an effective option for large, established ditch lily infestations where manual digging is impractical. The most successful approach involves using a systemic, non-selective herbicide, such as one containing glyphosate. Systemic herbicides are absorbed by the leaves and then translocated throughout the entire plant, including the roots and tubers, to achieve complete kill.
When applying a foliar spray, it is beneficial to use a product formulated with a surfactant or to add a non-ionic surfactant to the mix. The waxy, strap-like leaves of the ditch lily naturally repel water, and a surfactant helps the herbicide droplets adhere to the foliage for better absorption. Spray coverage should be thorough, aiming to coat the leaves without causing excessive runoff.
For areas with established ornamental plants nearby, the “cut-and-paint” method offers a more precise application. This involves cutting the foliage close to the ground and immediately applying a concentrated glyphosate solution directly to the freshly cut surfaces of the stems. This method minimizes the risk of spray drift or contact with desirable plants.
The timing of the herbicide application influences its effectiveness against the ditch lily’s root system. The most advantageous period is in the late summer or early fall (late August through October). During this time, the plant is preparing for dormancy and actively moving carbohydrates and nutrients from its leaves down to its underground storage organs.
By applying a systemic herbicide during this downward flow of resources, the chemical is efficiently pulled deep into the tubers and rhizomes, maximizing the destruction of the root network. Always wear appropriate personal protective equipment, such as gloves and eye protection, and carefully follow all instructions and warnings listed on the herbicide label. Repeat applications may be necessary the following spring if new growth emerges.