“Sticky Bob” refers to Commelina diffusa, also known as spreading dayflower or climbing dayflower. This herbaceous plant is widely distributed across tropical and subtropical regions. Known for its vigorous growth, it frequently appears in gardens and cultivated areas, often considered a weed. However, it also has characteristics that make it ecologically interesting.
Recognizing Sticky Bob
Identifying Commelina diffusa requires observing its physical characteristics. It features creeping stems that often ascend, branching and rooting readily at nodes. Stems can extend over one meter, varying from smooth to sparsely bristly. Leaves are lance-shaped to ovate, 3 to 12 cm long and 0.8 to 3 cm wide, though North American populations may have smaller leaves. Red-striped leaf sheaths clasp the stem base.
Flowers are typically bright blue, sometimes lavender. Each flower has three petals: two larger upper petals and one smaller lower petal. They are short-lived, often opening only in the morning. A unique, folded, leaf-like bract (spathe) encloses the flower stalks, usually 1 to 4 cm. Small, dry capsules contain typically five dark brown, ovoid seeds. A fibrous root system anchors the plant.
Understanding Sticky Bob’s Growth Habits
Commelina diffusa thrives in moist, well-drained soils. It adapts to full sun to partial shade, often found in swamps, marshes, and riverbanks. It prefers moderate temperatures and humidity, growing year-round in suitable climates without dormancy.
It exhibits rapid growth, especially in warmer seasons, quickly establishing lush foliage. Its aggressive spread stems from two primary mechanisms: seed dispersal and vegetative propagation. Stem fragments readily root at nodes, forming dense mats that displace other vegetation. A single plant can produce up to 1,600 seeds, contributing to its widespread presence.
Effective Management Strategies
Managing Commelina diffusa requires persistent effort due to its resilient growth habits. Manual removal is effective for small infestations, but requires uprooting the entire plant, including all roots and stolons. Leftover stem fragments easily regenerate, especially in moist soil, making complete removal challenging.
Cultural practices suppress its growth. Applying a thick layer of organic mulch (2 to 4 inches deep) blocks sunlight and hinders new plant establishment from seeds. Improving soil drainage also makes the environment less favorable for this moisture-loving plant. Encouraging competitive, desirable plants, like sweet potatoes or peas, helps outcompete Commelina diffusa for resources and light.
Chemical control can be considered for larger infestations, though Commelina diffusa is difficult to control chemically. Glyphosate can be effective on very small seedlings, but mature plants often show tolerance, requiring higher doses or multiple applications. Other effective herbicides include 2,4-D, bentazone, or mixtures with paraquat and diuron. Always ensure responsible and safe application, following product instructions carefully.
Preventive measures limit its spread. Regularly inspecting garden tools and equipment for plant fragments prevents accidental dispersal. Avoiding contaminated soil or compost also prevents its introduction. Early detection and prompt removal of new plants before they establish roots or produce seeds significantly reduces future management challenges.
Ecological Role and Potential Uses
While often viewed as a weed, Commelina diffusa plays ecological roles and has historical uses. Its sprawling growth serves as groundcover, aiding erosion control, particularly on slopes. It also provides habitat for invertebrates and contributes to soil coverage.
Historically, Commelina diffusa has been used in traditional practices. Its leaves are rich in Vitamin C; early Australian settlers consumed it to prevent scurvy. In traditional Asian medicine, it has been used for fever-reducing (febrifugal) and diuretic properties. It has also been applied to wounds, treated inflamed eyes, and served as a digestive aid.
While some parts are edible as a cooked vegetable, proper identification is essential. A blue dye can also be extracted from its petals for painting.