Family: Commelinaceae

Commelina diffusa, commonly known as climbing dayflower or honohono, is a fast-growing, creeping perennial herb native to tropical regions of Africa, South and Southeast Asia, East Asia, and parts of the Pacific. It has succulent, spreading stems that root easily at the nodes, smooth green leaves, and small but striking blue flowers that usually open in the morning. The plant thrives in moist soils and partial shade and is commonly found in gardens, lawns, agricultural areas, and along roadsides. In some regions, it has been used as a groundcover, ornamental, or in traditional medicine, and it is often appreciated for its rapid growth and attractive flowers.

In Hawaiʻi, however, climbing dayflower poses significant ecological concerns. Its ability to spread vegetatively allows it to form dense mats that smother surrounding vegetation and outcompete native plants for space, light, and nutrients. This species is naturalized on Kuaihelani (Midway Atoll), Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and Hawaiʻi Island, highlighting its adaptability and invasive potential across the state. Once established, it can be difficult to manage, particularly in wet or disturbed habitats. Because of its aggressive growth and widespread naturalization, planting Commelina diffusa is discouraged, and choosing native or low-risk alternatives is strongly recommended to help protect Hawaiʻi’s unique ecosystems.

High Risk Traits:

• Invasive: Naturalized globally, displaces native plants.
  
• Harmful Weed: Environmental & agricultural pest, reduces crop yields.
  
• Fast Reproduction: Annual, prolific seeder, spreads vegetatively when cut.
  
• Easy Dispersal: Spreads via human activity, water, and possibly birds.
  
• Allelopathic: Inhibits growth of nearby plants.
  
• Disease Host: Harbors crop-damaging nematodes.
  
• Tolerant: Shade-tolerant, adapts to various soils, benefits from disturbance.
  
• Smothering Growth: Creeping habit forms dense ground carpets.
  
• Herbicide Resistance: Some biotypes resist common herbicides.

Low Risk Traits:

• Non-Toxic: Edible, safe for humans and livestock.
  
• No Physical Defense: Lacks spines, thorns, or burrs.
  
• Low Fire Risk: Herbaceous, does not increase fire hazard.
  
• Limited Dispersal: Seeds not wind-adapted; no external animal attachment.
  
• Climate Limited: Primarily a risk in warm climates, not temperate zones.