Abutilon theophrasti (commonly known as velvetleaf) is a summer annual weed native to Asia. For those not familiar with the species, plants are tall (to 1-2 m) and erect with green- or purple-colored stems that branch at higher leaf axils (Warwick and Black 1988). The leaves are heart-shaped and covered in soft hairs (hence the name ‘velvetleaf’) (Warwick and Black 1988). Pale yellow- to yellow-orange-colored flowers are borne singly in the axils of leaves or in small clusters on short branches in the plant canopy (Warwick and Black 1988). Seed capsules are cup-shaped, hairy and either brown- or yellow-colored (Warwick and Black 1986, Kurokawa et al. 2003). Individual seeds are kidney-shaped and grey to black in color (Warwick and Black 1986).

Figure 1. The characteristic heart-shaped leaves and kidney-shaped seeds of velvetleaf (Abutilon theophrasti)

Velvetleaf, like kenaf (Hibiscus cannabinus L.), beach hibiscus (Hibiscus tiliaceus L.), roselle (Hibiscus sabdariffa L.), and other members of the Malvaceae, has been, and still is cultivated for its stem fibers, which are used in the manufacture of rope, twine, and other materials (Dempsey, 1975). Velvetleaf was domesticated in central China, where it was grown for its soft and lustrous stem fibers (Dempsey 1975). Stem tissue has been used alone to produce twine, paper, sacking, netting, and coarse cloth, or blended with silk to make satin and brocades (Dempsey 1975, Spencer 1984). It has been suggested that velvetleaf was introduced, purposely, to colonial America to serve as a fiber source for the manufacture of cordage and other necessities (Dempsey 1975, Spencer 1984).

Although velvetleaf was actively cultivated in the 1700’s, the crop was never economically successful. In the 1800’s, there was frustration with the United States Navy’s dependence on rope produced in Eastern Europe and Russia; as a consequence, farmers were asked to make better use of the plant. Don’t forget, the Navy we recognize now wasn’t the navy we had back then; the ships were wooden and relied on sails for propulsion. And sails relied on rope, lots and lots of rope. For example, USS Constitution was a three-masted frigate with masts that ranged from 173 to 220 feet in height and could require more than 4 miles of rigging. In short: our country didn’t want our military to be dependent on foreign rope!

Whether it was brought here intentionally or not, it is safe to say that velvetleaf has become an established pest. As of January 2017, the USDA PLANTS database indicated that the species can be found in the 48 contiguous states and 9 Canadian provinces.

Now for the boring stuff.

Not all velvetleaf is created equal; it looks as though crop and weedy biotypes exist and differ in their growth and development. Describing the defining characteristics separating the crop and the weedy forms will help us understand responses to selective pressure in velvetleaf and crop-weed evolution in general.

Scientists have shown that a substantial amount of variability exists among velvetleaf accessions with respect to physical appearance, flowering phenology, and capsule color. In 2003, while working in John Cardina’s lab (Ohio State), I conducted a study to characterize the morphological and phenological variation present in velvetleaf accessions from Asia, Japan, India, Europe, Eastern Africa and North America. Velvetleaf seeds (80 accessions from 21 countries) were obtained from Dr. R.N. Andersen (USDA-ARS, retired) and the U.S. National Plant Germplasm System (NPGS) (NPGS samples used in our study were originally collected by the N.I. Vavilov Institute of Plant Industry between 1916 and 1940. Kurokawa et al. 2003). Replicate samples from each accession (a minimum of 5 to 7 plants, each derived from a different parent) were grown in a greenhouse at the Ohio Agricultural Research and Development Center (OARDC) in Wooster, OH. A total of 586 plants from 77 accessions were evaluated. Some of the attributes that were described included: stem height (mm) at 4, 7 and 10 weeks; number of days from sowing to flowering; stem height (mm) at flowering; duration of flowering (days); number of days from sowing to harvest; final height (cm) at harvest; number of nodes at harvest; number of capsules (seed pods) per plant at harvest; and capsule color.

Figure 2. and example of the differing colored capsules (yellow and black) observed in the velavetleaf accessions.

Results from our study indicate that accessions producing yellow-colored capsules differed significantly from those possessing brown-colored capsules. In general, plants with yellow seedpods were:

1) taller,

2) flowered later and for a shorter period of time,

3) and produced fewer seedpods per plant as compared to plants producing brown capsules.

Figure 3. Some of the morphological and phenological differences between velevetleaf biotypes producing yellow and brown capsules.

Our results are in agreement with Kurokawa et al. (2003) who reported that the NPGS accessions could be divided into two forms (“crop” and “weedy”) based on a comparison of their morphological and phenological characteristics. According to Kurokawa et al.(2003), crop forms (which were primarily collected from Africa, Asia and India) are:

1) possessed yellow-colored seed capsules,

2) were taller at all observation dates,

3) were minimally branched, and

4) had a longer vegetative phase than their weedy counterparts.

Figure 4. Our multivariate analyses demonstrating the collective morphological and phenological separation between the crop and weedy biotypes.

Weedy accessions (which were typical of Europe and the US) were shorter, more branched, and produced greater numbers of non-dormant seeds in brown seedpods (Kurokawa et al. 2003). The differences among the crop and weedy forms suggests that they have been subjected to different selection pressures. An upright, minimally branched form of velvetleaf would allow for the easier harvest of stem fibers (Kurokawa et al. 2003). Velvetleaf appears to be determinant with respect to growth; an increase in the duration of the vegetative phase would result in greater stem height, which is directly related to fiber yield (Kurokawa et al. 2003). A rapid transition between the vegetative and reproductive phases could be an advantage for the weedy velvetleaf, as this allows for increased reproduction potential (Baker 1974, Patterson 1985). Increased branching is associated with increased capsule production because velvetleaf flowers are produced on short branches that develop from leaf axils in the canopy of the plant (Warwick and Black 1988). Kurokawa et al. 2003) speculated that the yellow capsule color, which is a recessive trait, may have served as a tool for preventing genetic contamination from the weedy forms.

Baker, H.G. 1974. The evolution of weeds. Annual Review of Ecology and Systematics 5:1-24.

Dempsey, J.M. 1975. Fiber Crops. University of Florida Press. Gainsville Florida

Kurokawa, S., N. Shimizu, S. Uozumi, and Y. Yoshimura. 2003a. Intra-specific variation in morphological characteristics and growth habitat of newly and accidentally introduced velvetleaf (Abutilon theophrasti Medic.) into Japan. Weed Biology and Management 3:28-36.

Kurokawa, S., N. Shimizu, S. Uozumi, and Y. Yoshimura. 2003b. ISSR variation in a worldwide collection of velvetleaf (Abutilon theophrasti) and the genetic background of weedy strains mingled in grains imported into Japan. Weed Biology and Management 3:179-183.

Patterson, D.T. 1985. Comparative ecophysiology of weeds and crops: Pages. 101–130. In S. O. Duke, ed. Weed Ecophysiology. Volume. 1 Reproduction and Ecophysiology. CRC Press. Boca Raton, FL.

Spencer, N. R 1984. Velvetleaf, Abutilon theophrasti (Malvaceae), history and economic impact in the United States. Econ. Bot. 38: 407-416.

Warwick, S.I. and L.D. Black. 1986. Genecological variation in recently established populations of Abutilontheophrasti (velvetleaf). Canadian Journal of Botany 64:1631- 1643.

Warwick, S.I., and L.D. Black. 1988. The biology of Canadian weeds. 90. Abutilon theophrasti. Canadian Journal of Plant Science 68:1069-1085.

This post is an updated version of a blog contribution originally published at the UCANR WeedRIC website.