Herbicide Application Timing Critical to Control Exotic Hawkweeds

Herbicide Application Timing Critical to Control Exotic Hawkweeds

This article summarizes field studies established on meadow hawkweed at two sites near Santa, Idaho by Dr. Tim Prather, University of Idaho. Selective herbicides such as Milestone® specialty herbicide have shown to control hawkweeds and release grasses and desirable native forbs. Strategically timed herbicide applications can improve hawkweed control and promote establishment and maintenance of grass cover.


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Identification and Management of Absinth Wormwood

Identification and Management of Absinth Wormwood

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.

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Managing Invasive Nightshades (Horsenettles) in Natural Areas and Pastures

Managing Invasive Nightshades (Horsenettles) in Natural Areas and Pastures

Silverleaf nightshade (Solanum elaeagnifolium) and Carolina horsenettle (Solanum carolinense), also known as horse nettle or bull nettle, are deep-rooted, herbaceous, perennial plants in the nightshade family. Article discusses distribution and management of the two invasive nightshades

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Have Burs Will Travel

Have Burs Will Travel

Cocklebur or Burdock—What’s the Difference? Common cocklebur (Xanthium strumarium L.) and common burdock (Arctium minus) are members of the sunflower family. This article describes how the two weeds differ in their life cycle, growth form, flower type, and seed heads.

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Managing Autumn Olive in Natural Areas

Autumn olive is an invasive woody shrub or small tree that grows to about 20 feet in height. The plant is commonly found invading open and early-successional woodlands, abandoned agricultural fields, and edges of streams and rivers.

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Autumn Olive and Russian Olive—What’s the Difference?

Autumn Olive and Russian Olive—What’s the Difference?

Autumn olive (Elaeagnus umbellata) and Russian olive (Elaeagnus angustifolia) are invasive, deciduous, woody shrubs or small trees that were introduced for landscaping, soil stabilization, and wildlife food/cover. Both plants became invasive in riparian areas, open forests, lake shores, and abandoned fields.

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Identification & Management of Purple Loosestrife

Identification & Management of Purple Loosestrife

Purple loosestrife (Lythrum salicaria L.) is a perennial, rhizomatous forb that invades riparian areas and other waterways throughout most of the U.S. and southern Canada  The invasive plant threatens biodiversity of wetlands. Successful management requires integrating various management methods.

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Native and Exotic Thistles: Who's Jekyll, Who's Hyde?

Native and Exotic Thistles: Who's Jekyll, Who's Hyde?

There are five common exotic thistles (exluding Centaurea spp., both the starthistles and knapweeds) in the western U.S. that are problematic to some degree across a variety of habitats.

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Spotted Knapweed Management with Herbicides

Spotted Knapweed Management with Herbicides

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.

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Canada Thistle Management with Herbicides

Canada Thistle Management with Herbicides
Canada thistle (Cirsium arvense) is a perennial plant with extensive spreading roots that rapidly forms dense colonies. Vegetative shoots arise from adventitious buds located on Canada thistle roots. Canada thistle also spreads by seed; each shoot can produce more than 1,000 seeds. Plants grow from 1 to 4 feet tall and have spiny, lance-shaped leaves. Purple, lavender, or sometimes white flower heads typically appear from June to October. Read More

Saltcedar and Russian Olive Management

Saltcedar and Russian Olive Management

Saltcedar (Tamarix ramosissima, T. pentandra, T. chinensis, and T. parviflora) and Russian olive (Elaeagnus angustifolia L.) are rapid growing, non-native deciduous trees that were introduced into the United States for erosion control (saltcedar), windbreaks (Russian olive) or as ornamental plantings.

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Dormant Season Management Recommendations for Russian Olive

Dormant Season Management Recommendations for Russian Olive

Russian olive (Elaeagnus angustifolia) is a rapid-growing, deciduous, woody shrub or small tree that is invasive in riparian areas, lake shores and natural areas. The invasive plant can cause serious ecological changes to riparian habitats with impacts to wildlife and watershed values, agriculture, and recreation. There are several management options for Russian olive depending on tree size, density, and environmental constraints. The following information summarizes herbicide options for Russian olive management that can be used any time of the year including winter and early spring when trees are dormant. 

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Proper Herbicide Application Timing Maximizes Invasive Plant Control

Proper Herbicide Application Timing Maximizes Invasive Plant Control

Spring and early summer can be excellent times to control actively growing invasive plants with herbicides. Applying herbicides to the target plant at the optimum growth stage is important to maximize control. The following guidelines provide information on the best application timing and rate to control key invasive plants.

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Biennial Thistle Management

Biennial Thistle Management

Several biennial thistles are problematic in North America including bull thistle (Cirsium vulgare), musk thistle (Carduus nutans), plumeless thistle (Carduus acanthoides), and Scotch thistle (Onopordum acanthium). 

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