INVASIVE FACT SHEET Japanese

Description: Problem: Origin:

Japanese hops is a This species is considered Japanese hops is native dioecious, fast-growing, to be invasive and has to Japan and eastern herbaceous annual a high reproductive rate, China. It was introduced in the Cannabinaceae rapid growth rate, long to the United States as family. Its are range dispersal, and broad an ornamental garden simple, opposite, heart- photosynthetic range. plant. Unlike its close shaped and palmately Japanese hops can form relative, Humulus divided, usually into dense, almost solid, lupulus (common hops), 5 lobes. Flowers are stands that outcompete Japanese hops has little greenish and bloom mid native vegetation and has value in the to late summer. Green the potential to displace industry. hops produced by female native riverbank and flood contain oval, plain vegetation. yellowish brown . begin growth in May. The seeds are believed Growth is rapid and the to remain viable in the vines quickly climb over soil for three years and adjacent vegetation. By are dispersed by wind late summer, vines can and water along rivers be up to 35 feet in length, and streams. The stems which can blanket nearby are 8-35 feet in length vegetation. and are covered with

rough hairs that are very Picture By: J. Randall @ http://tnc- irritating to bare skin. weeds.ucdavis.edu.

Pictures By: C. Evans @ www. IPSAWG Ranking: invasive.org Distribution: Invasive Plants Japanese hops can grow MEDIUM MEDIUM HIGH are a Threat to: in sandy, loamy, clay, acid, neutral and basic • Forests and soils. While it requires Ecological Potential for Difficulty of wetlands moist soil, it can grow Impact Expansion Control in semi-shade to no • Native plants shade environments. IPSAWG Recommendation: It threatens open • Perennial gardens woodlands, fields, prairies •Do not buy, sell or plant Japanese hops in Indiana. and riparian corridors. It •Help by eradicating Japanese hops on your property. • Wildlife is widespread throughout the eastern United States and ranges from Maine This ranking illustrates the results of an assessment conducted • Lakes and rivers by the Invasive Plant Species Assessment Working Group south to Georgia and (IPSAWG), which is made up of many organizations and agencies west to Kansas and concerned about invasive plant species. IPSAWG’s goal is to assess • Human health Nebraska. In Indiana, which plant species may threaten natural areas in Indiana and most populations are in develop recommendations to reduce their use in the state. • Farmland southern Indiana riparian For more information about IPSAWG and the assessment tool used areas, though a few to rank invasive species, visit their website: northern sites have been www.invasivespecies.IN.gov Date Prepared: 05/07 reported. Control Methods: ALTERNATIVES to Japanese hops: Plants can be hand pulled flowering should damage within approximately and removed from the area the plant enough so it will three years. before seeds ripen. When not be able to flower and Always read and pulling the plants, attempt set . The seed bank follow pesticide label to remove as much of the is typically exhausted directions. rootstock as possible. Long sleeves, pants, and gloves are essential to Virgin’s Bower avoid skin irritation. It (Clematis virginiana) is likely that resprouts could occur from both the rootstock and the vines. An herbicide alternative is glyphosate (i.e. Roundup or Rodeo). Foliar application of glyphosate (mixed according to label directions) prior to Picture By: J. Randall @ http://tncweeds.ucdavis.edu. Trumpet Honeysuckle (Lonicera sempervirens) Eight Easy Ways to Combat Invasive Plants

You can help stop the spread of invasive plants by following these 8 easy guidelines: 1. Ask for only non- for invasive species, and and natural areas to assist invasive species when you remove invasives before ongoing efforts to diminish acquire plants. Request that they become a problem. If the threat of invasive Woolly Dutchman’s Pipe nurseries and garden plants can’t be removed, plants. (Aristolochia tomentosa) centers sell only non- at least prevent them from 7. Help educate your going to seed. Pictures By (Top to Bottom): D. invasive plants. community through Liebman, J. Lepore and S. Baskauf. 2. Seek information on 4. Clean your boots before personal contacts and in invasive plants. Sources and after visiting a natural such settings as garden Other Alternatives: include botanical gardens, area to prevent the spread clubs and civic groups. of invasive plant seeds. Virgina Creeper horticulturists, 8. Support public policies conservationists, and 5. Don’t release aquarium and programs to control (Parthenocissus plants into the wild. quinquefolia) government agencies. invasive plants. 3. Scout your property 6. Volunteer at local parks Crossvine (Bignonia capreolata) For More Information: : Not Recommended On this assessment and IPSAWG: American Bittersweet IPSAWG (Celastrus scandens) www.invasivespecies.IN.gov While American On identification and control techniques: Bittersweet is native The Nature Conservancy’s Wildland Weeds and non-invasive, www.tncweeds.ucdavis.edu nurseries often mislabel On native plant alternatives and sources: Oriental Bittersweet as American Bittersweet. It Indiana Native Plant and Wildflower Society is very difficult to find true www.inpaws.org American Bittersweet for This grant project made possible with United States Forest Service funds administered by sale. the IDNR, Division of Forestry.