Trumpetcreeper: One Tough Plant

Glenn Nice, Weed Diagnostician, Department of Botany & Plant Pathology, Purdue University

Trumpetcreeper (Campsis radicans) is a native perennial vine that is often found climbing fences, electric wire poles and, on occasion, running along the ground when there is nothing to climb. Its common name is appropriate because its most distinguishing characteristic is its bright orange trumpet-like flower. The accompanying picture shows Japanese beetles enjoying a smorgasbord of trumpetcreeper flower. Trumpetcreeper vines can reach a length of up to 40 feet, and leaves are oppositely arranged on the stems, with oppositely arranged leaflets in a pinnately compound leaf. Each leaf can have seven to 15 leaflets and each trumpetcreeper flower can produce a long pod¹.

Like several other problematic perennials, Canada thistle to name one, trumpetcreeper produces a deep root system that can produce new above ground stems.  Although trumpetcreeper can reproduce by seed, it is believed that root stock is the dominate mechanism of proliferation. Root stock cut 0.8 inches long can produce shoots eight weeks after planting². Stems continued to emerge when root stock was buried nine inches deep; however, planting depth from three to nine inches did not have any effect on total above ground biomass². To add to the fast spread of trumpetcreeper, it can also root where the stems touch soil. This would add to the ability to fragment into new plants.

For the most part, in Indiana trumpetcreeper is a weed that sits on the fence or the fringes of our row crops. Occasionally it can invade no-till fields, reducing soybean yield and becoming a nuisance at harvest time. It has been reported that 0.5 plants/m² can reduce soybean yield 18%³.

Many of the herbicides labeled for conventional soybean will provide suppression by burning or injuring the above ground portions of the plant when it is small. To control the plant you have to control the underground portions of trumpetcreeper by using a herbicide that will translocate. In one study the application of glyphosate at 1 lb ae/A (ae stands for “acid equivalent”) followed by a second application of 0.75 lb ae/A reduced biomass 89%⁴. The use of a split application was reported to reduce biomass to acceptable amounts, 0.16, 0.14, and 0.06 oz dry weight/yard² in three years, respectively⁴.  Triclopyr plus 2,4-D (Crossbow®) can also be used to suppress/control trumpetcreeper in non-crop, fencerows and grass pastures. The use of 1.5% v/v mixture or a 6 qt/A broadcast rate or 4 qt/A on permanent pastures can provide approximately 60 to 79% control.

References:
1) Trumpetcreeper or cow-itch: Campsis radicans.  Accessed 3/13/06.  Virginia Tech Weed Identification Guide. (http://www.ppws.vt.edu/scott/weed_id/cmira.htm).

2) Edwards, J.T. and L.R. Oliver.  2004.  Emergence and growth of trumpetcreeper (Campus radicans) as affected by rootstock size and planting depth.  Weed Technology 18:816-819.

3) Edwards, J.T. and L.R. Oliver.  2001.  Interference and control of trumpetcreeper (Campsis radicans) in soybean.  Proceedings of the Southern Weed Science Society 54:130-131.

4) Reddy, K.N.  2005.  Deep tillage and glyphosate-reduced redvine (Brunnichia ovata) and trumpetcreeper (Campsis radicans) populations in glyphosate-resistant soybean.  Weed Technology 19:713-718.

Click image to enlarge

Japanese beetles feeding on trumpet creeper