Twenty two different knapweed species (Centaurea sp) are well established in North America. Most are introduced opportunists that have aggressively invaded natural areas, pastures, open woodlands, rights-of-way, and disturbed areas. Brown (C. jacea), black (C. nigra) and meadow knapweed (C. ×moncktonii) are long-lived perennial plants that are problematic in the United States and southern Canada.Read More
Invasive plants often establish and flourish on steep, rough terrain that is difficult to access. This makes early detection and management difficult and hazardous work. Nigel Davis, a commercial applicator in Helena, Montana, understands the challenges involved with treating invasive plants in natural areas with ground-based equipment. This makes early detection and management difficult and hazardous work. Nigel Davis, a commercial applicator in Helena, Montana, understands the challenges involved with treating invasive plants in natural areas with ground-based equipment.Read More
Absinth wormwood (Artemisia absinthium L.) is a perennial broadleaf plant introduced as an ornamental into North America from Europe in 1841. The plant escaped cultivation and is now widely distributed in the U.S. and Canada. This article describes the biology, ecology, identification, and management of absinth wormwood in natural areas.Read More
Japanese chaff flower (Achyranthes japonica) is a highly invasive, non-native, perennial plant in the Amaranth family. This article discusses distribution and management of this non-native plant.Read More
Guy B. Kyser, Vanelle Peterson, Steve B. Orloff, Steven D. Wright, Joseph M. DiTomaso (2011). Invasive Plant Science and Management: July-September, Vol. 4, No. 3, pp. 341-348. http://wssajournals.org/doi/abs/10.1614/IPSM-D-11-00002.1Read More
A summary of research presented as a poster–Integrated Management of Yellow Starthistle with Burning, Aminopyralid (Milestone), and Revegetation–at the Western Society of Weed Science Annual Meeting, Reno, NV 2012 by Guy B. Kyser, Arthur W. Hazebrook, and Joe DiTomaso.Read More
Fall rain and cooler temperatures provide good conditions for extending the herbicide application season. The following species and many others can be effectively controlled in the fall. Follow the links for control recommendations for each species.Read More
This TechNote summarizes research on: 1) Integrating herbicides with other methods for managing yellow starthistle and 2) Controlling coast fiddleneck (Amsinckia menziesii)and yellow starthistle. Also included are practical management tips on herbicide rate and time of application to optimize yellow starthistle control.
Herbicides play an important role in integrated management of yellow starthistle and can be used alone or in combination with other techniques such as timely mowing, grazing, burning, or use of biological control insects.
The USDA Plants database lists more than 20 Rubus species (and associated hybrids) that were introduced to North America. Himalayan blackberry (Rubus armeniacus) and cutleaf blackberry (Rubus laciniatus) are the two most widespread of the invasive blackberry species.Read More
Fall is an excellent time to control invasive weeds with Milestone. Late summer and fall rains in many areas of the Central Plains and the West will provide land managers with a good opportunity to extend their application season.Read More
Undesirable or invasive woody vegetation threatens the biology and ecology of prairie grasslands and native woodlands. Removing invading woody species can be accomplished year-long, with fall, winter and early spring herbicide applications, extending your vegetation management efforts.
Plants in the carrot (Apiaceae) family share the characteristic of an umbel-shaped flower head. The family includes hundreds of plants, some that are valuable vegetables and herbs, and a few that are masters in chemical warfare. Accurate identification is important for management and avoiding accidental poisoning. This article reviews distribution, identification and management of three invasive, toxic plants in the carrot family: poison hemlock (Conium maculatum), wild parsnip (Pastinaca sativa), and giant hogweed (Heracleum mantegazzianum).Read More
The carrot (Apiaceae) family comprises 434 genera and about 3,700 species and is characterized by a flat-topped flower cluster, called an umbel. Water hemlock (Cicuta), one of several toxic members of this family, is considered to be the most toxic plant in North America. There are four species of water hemlock in North America, all highly poisonous and native to North America: spotted (C. maculata), western (C. douglasii), bulblet-bearing (C. bulbifera), and Mackenzie’s (C. virosa).Read More
Managing incompatible woody vegetation along utility and transportation rights-of-way (ROW) requires careful planning, consistent budgets, and judicious allocation of time and resources. When budgets or resources are inadequate, planned vegetation maintenance may be postponed to the following growing season or beyond. While delaying maintenance for even one year allows woody vegetation to increase in density and height, the actual increase in time and material to control the vegetation after one or more years of delayed treatment has not been determined.Read More
Spotted knapweed (Centaurea stoebe) is a tap-rooted perennial forb that spreads by seed. Seedlings and mature plants over-winter in a rosette stage and resume growth in early April. Spotted knapweed blooms from mid to late July through mid September.Read More