Wavy-leaf basket grass (Oplismenus undulatifolius) is a perennial plant that is native to parts of Asia, Australia, and southern Africa; it has also been accidentally introduced in parts of the United States, where it has become invasive. In its native range, wavy-leaf basket grass is an important food source for many species of butterflies.
I. Appearance and Characteristics
Oplismenus undulatifolius, commonly known as wavy-leaf basket grass, is a species of perennial grass from the family Poaceae that is native to Eurasia, specifically Southern Europe through Southern Asia. Due to its invasive nature, it can be found in countries such as Pakistan (Punjab & Kashmir), China, Japan, Korea, India, Australia, South Africa, and has since been introduced to the Mid-Atlantic United States. There are no recognized subspecies in Catalogue of Life.
Oplismenus undulatifolius is a shallow rooted perennial with stolons that may grow to several feet in length. The leaves of overwintering plants become brown and dead, but in the spring, new growth begins at the upper nodes of the stolons. In early fall, the sticky awns readily adhere to anything that brushes against them which makes for an effective mode of dispersal.
The species is 15–50 centimeters (5.9–19.7 in) long with leaf-blades being slightly lanceolate, ovate, and are 1–7 centimeters (0.39–2.76 in) long and 4–15 millimeters (0.16–0.59 in) wide. Its inflorescence is 2–8 centimeters (0.79–3.15 in) long and is made out of 5-11 cuneate fascicles which are 0.5–1.5 centimeters (0.20–0.59 in) in length and carry 2-6 spikelets. Spikelets are lanceolate just like leaf-blades, and are 2.5–4 millimeters (0.098–0.157 in) in length.
They are also glabrous and pubescent and have glumes which have smooth viscid awns which are 7–14 millimeters (0.28–0.55 in) long. The awns of lower glumes are purple, are 5–10 millimeters (0.20–0.39 in) in length and are 3-5 veined. The lower lemma is herbaceous and have 5-9 veins while the upper one is 5 veined with an awn that is 2–5 millimeters (0.079–0.197 in). The species apex have a stout that is 1–2 millimeters (0.039–0.079 in) long. Flowers and fruits grow from July to November.
This species grows particularly well in moist, shaded environments, in a variety of soil types. In Australia it grows in shady coastal forests at Coffs Harbour.
In its native range, Oplismenus undulatifolius is a food source for many species of Lepidoptera, including Elachista kurokoi, Helcystogramma fuscomarginatum, Mycalesis francisca, Mycalesis sangaica, Mycalesis zonata, Palaeonympha opalina, Stigmella oplismeniella, Ypthima akragas, Ypthima baldus, and Ypthima esakii.
As an invasive species
Accidentally introduced into the United States in Maryland and Virginia, this species spreads quickly and is becoming extremely invasive in forested natural areas in the Mid-Atlantic region across numerous counties in Maryland and Virginia.
The species was first reported in Maryland in 1996, growing around the Liberty Reservoir area and the northern section of the Patapsco River in Howard County. The grass spread quickly into connected natural areas in Baltimore and Carroll counties. By 1999 it was identified in Montgomery County at Wheaton Regional Park. In 2006 it was identified in Prince George’s County at Little Paint Branch Park [2], the adjacent Beltsville Agricultural Research Center-East and the National Greenbelt Park. It had crossed into Virginia by 2004 where it was found growing at an 80-acre (320,000 m2) site in Shenandoah National Park, and in a 20–30-acre (81,000–121,000 m2) site at the Fraser Preserve along the Potomac River in Fairfax County.
Once a population has become established, complete eradication from a site has proven to be extremely difficult due to a long-lived perennial life cycle, a long seed germination season (April–November), and considerable seed mobility of the species.
II. How to Grow and Care
Wavy-leaf basket grass thrives in moist, well-drained soil with partial to full shade, making it suitable for understory environments. Special care points include avoiding direct sunlight, which can scorch its delicate leaves, and maintaining consistent soil moisture without waterlogging. The species is known for its easy care, resilient nature, and tolerance of low light conditions.
Sunlight
Wavy-leaf basket grass flourishes in conditions of partial sun, which permits a balance between shade and light exposure for optimal growth. With a tolerance for full shade, wavy-leaf basket grass is adaptable to less illuminated environments, but prolonged absence of adequate light may lead to reduced vigor and sparser foliation. Wavy-leaf basket grass’s leaves can adjust to light availability, typically exhibiting a more vibrant green in ideal lighting. Recommended for outdoor growth, wavy-leaf basket grass performs best when planted under the dappled light of canopy trees or in areas with morning sun and afternoon shade, avoiding locations with excessive direct sunlight that can overwhelm its delicate foliage.
Watering
Originating from the understory of tropical rainforests, wavy-leaf basket grass thrives in high humidity environments and is accustomed to the consistent moisture found there. This species exhibits a preference for evenly moist soil, maintaining a balance without being waterlogged. It requires watering every week to mimic its natural habitat’s conditions. Transitioning smoothly into care requirements, wavy-leaf basket grass is more commonly grown outdoors where it can benefit from natural rainfall patterns. As an evergreen plant, wavy-leaf basket grass’s water needs remain consistent throughout the year, ensuring its foliage stays lush and vibrant.
Fertilizing
For optimal growth, wavy-leaf basket grass requires periodic fertilization with mulch or compost. This enriches soil fertility, promoting stronger roots and lusher foliage. Apply a light layer biannually, during the growing season, to sustain nutrient levels. Excessive quantities should be avoided to prevent root burn. Variations in fertilization may be necessary, with less needed in dormant seasons. Always ensure even distribution around wavy-leaf basket grass, taking care not to disturb its shallow root system. This approach suits all gardening levels, ensuring wavy-leaf basket grass’s vitality.
Propagation
Native to shaded forest floors, wavy-leaf basket grass thrives in indirect light and moist, well-draining soil. It reproduces vegetatively through division. Gardeners can separate the densely clustered roots during active growth. Careful handling of root balls encourages successful establishment in new locations. Regular watering post-transplantation ensures the rooted divisions of wavy-leaf basket grass acclimate and proliferate, maintaining the delicate balance of moisture wavy-leaf basket grass naturally prefers.
Transplanting
For the vibrant wavy-leaf basket grass, the optimal transplanting time is between the awakening of spring and its full bloom – promoting robust growth. Choose a shady nook with moist soil. A gentle touch ensures its delicate roots settle in comfortably.
