Donaldson, S. and Hanson Mazet, W. 2013, A Northern Nevada Homeowner’s Guide to Identifying and Managing Poverty Sumpweed, Extension | University of Nevada, Reno, FS-13-15

Other common names

Povertyweed, bozzleweed, death-weed, salt sage, small-flowered marsh elder

Scientific name

Iva axillaris

Family

Asteraceae

Description

Poverty sumpweed grows to 2 feet tall in large colonies in disturbed sites. The leaves have a strong odor most people find unpleasant. When touched, the foliage can cause contact dermatitis in sensitive people.

Growing sumpweed

Typical plant growing in a disturbed site. Photo by S. Donaldson.

Leaves

Grayish-green, lobed and covered with short, bristly hairs. Oppositely attached to the stem toward the bottom of the plant, and alternately attached above.

Sumpweed leaf

Stems

Gray-green, bristly, upright and branched.

Flowers

Produces greenish male and female flowers on the same plant during the summer. Male flowers hang or nod at the ends of branches. Female flowers are spiny and are found in the leaf axils.

Sumpweed flower

The flower clusters occur where the leaves meet the stem. Photo by W. Hanson Mazet.

Roots

Grows deep, woody creeping roots.

Sumpweed roots

Plants can sprout from dormant roots after long periods. Seedlings are uncommon. Photo by W. Hanson Mazet.

Native to

Western North America

Where it grows

Salt marshes, alkali plains, roadsides and pastures, and sites disturbed by cultivation or overgrazing

Life cycle

Perennial (lives longer than two years)

Reproduction

Reproduces by creeping roots and seed

Control methods

Poverty sumpweed can be difficult to control due to its deep, spreading root system. As with all perennials, the roots must be killed to effectively control this plant.

Mechanical

Cultivation may spread root fragments and is not recommended. Hand pulling is difficult and may cause allergic symptoms in people; wear gloves and pull regrowth frequently. Mowing is not effective, as plants regrow.

Cultural

Plant desirable vegetation to help suppress it.

Biological

No biological controls are commercially available. Livestock do not find it palatable, and it may be toxic to livestock when eaten.

Chemical

Try broadleaf-selective herbicides such as 2,4-D or 2,4-D + dicamba on actively growing plants. Dicamba can persist for several months and may damage desirable plants in the area treated. Glyphosate is not recommended.

References

Calif. Dept. of Food and Agriculture. 2012. Iva genus, cdfa.

DiTomaso, J.M. and E.A. Healy. 2007. Weeds of California and Other Western States. University of California Publication 3488.

UC Berkeley Jepson Manual. 2012. Iva axillaris, UC/JEPS.

USDA-NRCS Plants Database. 2012. PLANTS profile for Iva axillaris, USDA.

Whitson, Tom D. (editor). 2009. Weeds of the West, 10th edition. University of Wyoming, Jackson, Wyoming.

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