Climbing Hemp Vine

Climbing Hemp blooming in a marshy littoral zone of a Central Florida lake.

This native species is Mikania scandens in the scientific literature.  Colloquially it is called climbing hempvine, climbing hempweed, hempweed, and louse-plaster.  But is often confused with an extremely invasive cousin, Mikania micrantha, also known as "Mile-a-Minute."  The invasive Mile-a-Minute looks very similar to the native but has lighter green leaves.

Follow Phillip

@majikphil

How to tell the invasive from the native? 

Climbing hempweed (Mikania scandens) looks very similar to Chinese creeper, but there are some differences. Mile-a-minute tends to grow in disturbed habitats, whereas climbing hempweed favors natural habitats. Mile-a-minute has very rapid growth compared to climbing hempweed, and has pale green or yellow-green leaves with green petioles and white flowers, whereas climbing hempweed has medium-green leaves with reddish petioles and pinkish flowers. The other similar species, Florida Keys hempvine (Mikania cordifolia), has hairy leaves and stems and larger flower heads compared to mile-a-minute and climbing hempweed.

Mile-a-minute is a major environmental and agricultural threat, Climbing Hempweed is not.  The former is listed as one of the 100 top invasive species on earth.  It produces 10s of thousands of fine, wind-blown seeds that easily disperse over vast areas.

The plants pictured here have more olive-green-colored leaves and are not growing insanely fast so they more resemble the native Climbing Hempweed.

Little Metalmark Host

The pappus-tipped seeds that are dandelion-like, are dispersed on the wind or on clothing or fur. The plant also reproduces vegetatively by rooting from the nodes on sections of stem.  The climbing herbage can become weedy and dense, sometimes covering other vegetation. It also has allelopathic effects on other plants.  That is to say that Climbing hemp is like a natural herbicide for other plants in the area, stunting or killing them outright with its presence.  

Mikania scandens contains the highly allelopathic active compound mikanolide.  Mikanolide is known to possess antibacterial properties and is studied both as an antibiotic and as a natural herbicide.

This is a host plant for the larvae of the Little Metalmark (Calephelis virginiensis), and the adult consumes the nectar.

This specimen is growing into a flooded forest on a Central Florida lake.  It is in full bloom in late October.  The plants prefer swampy habitat but can also be found in hammocks and sandhills in Florida.

Follow Phillip

@majikphil