HPIPM:Venice mallow

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Rosanae
Order	Malvales
Family	Malvaceae
Genus	Hibiscus

Scientific Name

Hibiscus trionum

Common Name

Venice mallow

Venice mallow (Hibiscus trionum)

Compiled by Jeff Edwards, University of Wyoming, Goshen County Extension.

and Marjolein Schat, Montana State University from the following sources:

http://plants.usda.gov/java/profile?symbol=HITR

http://weedalert.com/weed_pages/wa_venice_mallow.htm

http://www.mda.state.mn.us/plants/badplants/mallow.htm

http://www.cottoncrc.org.au/content/Industry/Publications/Weeds/WeedIdentificationTools/Weedsbycommonnames/Narrowleafbladderketmia.aspx

Identification and Life Cycle

Venice mallow (Hibiscus trionum) is a non-native annual in the mallow family (Malvaceae). Venice mallow has several additional common names including flower-of-an-hour, bladder ketmia, modesty, rosemallow, and shoo-fly. Venice mallow has an upright growth habit and can reach 10 - 18 inches in height. The stems are erect, covered with hairs and branch from the base. The leaves are deeply cleft into 3 to 5 coarsely toothed lobes and form on long petioles. The lower stems and petioles can be a red to purple in color. Venice mallow has a fibrous root system with a weak taproot. The flowers of Venice mallow are very showy and a light sulfur-yellow color with a deep red to purple center. Venice mallow is nicknamed "flower-of-an-hour" because flowers will only last several hours before the petals drop. Seeds develop in a globe-shaped to ovoid 0.5 to 1 inch, five celled capsule surrounded and enclosed by a strongly veined and inflated calyx. Each capsule contains several heart to kidney shaped rough dark brown or gray to black seeds.

Habitats

Venice mallow tolerates drought and gravely soils. It is also noted to tolerate alkaline soils. Venice mallow can infest nurseries, orchards, gardens, roadsides cultivated fields and open waste areas.

Impacts

The plant is a common weed of irrigated and dry land cotton, sorghum, sunflowers, maize and other summer crops.

Biology and Ecology

Seedlings emerge in successive seedling flushes. They can emerge at any time throughout the year after rainfall or irrigation. The densest flushes in excess of 200 seedlings/square yard are observed during the spring – autumn period. Soil disturbance increases seedling emergence. Rapid growth occurs, with flowering starting within 30 days. Flowering occurs throughout summer and autumn (June through September), with large numbers of flowers observed a week or more after rainfall and irrigation. Flowers open for only part of a day, or at most one day and are self pollinated. Mature seed is also set rapidly, within 46 days. Seed production peaks in summer and early autumn but can continue year round on plants growing in sheltered conditions. Between 1,500 and 16,000 seeds can be produced on medium sized plants, and seed can be produced on plants that are 2 inches tall. Plants are moderately frost sensitive, although some plants may persist in sheltered situations. The seed has strong dormancy after being shed with very little fresh seed germinating. Seed persists for a long period in the soil with 65% seed survival after two years.

Biological Control

There is currently no biological control program for Venice mallow.

Mechanical and Cultural Control

Due to longevity of the seeds, it is crucial to mow or remove the plants prior to flowering and seed development. Following agronomic practices such as watering and mowing will help to prevent infestations of Venice mallow.

Chemical Control

Venice mallow is best controlled by herbicides in late spring when plants are young. When using herbicides alternate products with different modes of action to aid in resistance management. Currently there are at least 73 products registered for use on Venice mallow representing 12 of the 27 herbicide groups (defined Modes of Action).

For herbicide recommendations for specific grain rotations and weeds in Montana, please see the MSU Herbicide Chooser Tool.

Examples of herbicides that can be used to manage Venice mallow

Consult herbicide labels for additional rate, application, and safety information. Additional herbicide information can be found at http://www.greenbook.net.

Herbicide Active Ingredient trade name	Mode of Action	Product per Acre	Application Time or Growth Stage
Alfalfa
Imazamox	Inhibition of acetolacetate synthase ALS (acetohydroxyacid synthase AHAS)
*Raptor		4 - 6 ounces	Apply when the seedling alfalfa is in the second (2nd) trifoliate stage or larger and when the majority of the weeds are 1-3 inches tall. When applied to alfalfa grown for seed, apply before bud formation. Apply to established alfalfa in the fall, winter, or in the spring to dormant or semi-dormant alfalfa,or between cuttings. Any application should be made before significant alfalfa growth or regrowth (3 inches). A maximum of 0.047 lb imazamox ae/acre (6 oz Raptor/acre) per season may be applied to alfalfa.
Grass Grown for Seed
Dicamba	Action like indole acetic acid (synthetic auxins)
*Clarity		8 - 64 ounces	Apply 8 - 16 fluid ounces on seedling grass after the crop reaches the 3 - 5 leaf stage. Apply up to 64 fluid ounces on well-established perennial grass. For best performance, apply when weeds are in the 2 - 4 leaf stage. DO NOT apply Clarity after the grass seed crop begins to joint.
Wheat
Dicamba	Action like indole acetic acid (synthetic auxins)
*Banvel		2 - 4 ounces	Apply to fall seeded wheat before wheat reaches the jointing stage, apply to spring seeded wheat prior to the 6-leaf stage. Apply when weeds are in the 2-3 leaf stage.
Barley
Dicamba	Action like indole acetic acid (synthetic auxins)
*Banvel		2 - 4 ounces	Apply to fall seeded before the jointing stage and to spring seeded barley before the 4 leaf stage. Apply when weeds are in the 2-3 leaf stage

The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality.

References

For more information and images please visit IPM Bugwood. http://www.ipmimages.org/search/action.cfm?q=venice%20mallow&Start=1&results=12