Gorse is a hardy evergreen shrub originally native to Western Europe, where it has long been of agricultural, ecological, and cultural importance, particularly within the British Isles. Today it has been introduced to and can be found growing freely in North America (particularly Oregon and California), South America, Australia, New Zealand, Hawaii, Sri Lanka, and the Falkland Islands. It is well-adapted to a large range of growing conditions, including very rocky soils, drought conditions, or highly disturbed ground. It prefers areas with high sun exposure and can often be found growing on coastal bluffs and cliffs, though it occurs in inland regions as well.
Gorse overtaking the cliffside at Nelscott Beach
Closeup of flowers and spines
Physical Description
From a distance, gorse is visually similar to Scotch broom, with a similar scraggly, branching growth habit and bright yellow blooms. Closer up, however, gorse is easily distinguishable from the sharp, dense spines that cover the plant in place of its leaves. Gorse may reach up to ten feet tall, but often takes on a lower-growing form when found on wind-exposed bluffs. Its yellow flowers are most abundant from March to May, but some flowers may be present throughout most of the year.
Why is Gorse a Problem?
Gorse, being extremely hardy and fast-growing, easily overtakes most areas it is introduced to, pushing out native plants along the way. It is also highly flammable. These two factors combined pose serious concerns for communities where gorse becomes heavily established. In fact, the initial introduction of gorse to the West Coast eventually led to the near-complete destruction of the town of Bandon in 1936. The town’s founder, in homage to his birthplace, named the seaside community after his hometown of Bandon, Ireland, and brought with him a plant known as Irish hedge- aka gorse. Between 1852 and 1936 “Irish hedge” spread unchecked, until one day sparks from a forest fire several miles from town were blown into a gorse patch. Flammable oils in the plant greatly accelerated the fire, destroying most of the town’s buildings and killing ten of its residents. However, as fire is an intrinsic part of gorse ecology, the plant’s population soon recovered and persists in large numbers to this day.
Due to both the immense safety risk posed by uncontrolled gorse and the threat posed to sensitive coastal species such as the Oregon silverspot butterfly, hoary elfin butterfly, snowy plover, and pink sand verbena, Lincoln SWCD has undertaken a new gorse control program within Lincoln County. Please contact the District if you believe you have gorse occurring on your property!
Controlling Fennel
Gorse may be manually controlled by hand-pulling, use of a weed wrench, or digging. So long as the tap root is fully removed, the plant will not resprout. Be sure to monitor the surrounding area for at least several years afterwards, as seeds that have previously dropped from the plant can remain viable for decades.
In locations where the terrain, soil type, or scale of infestation makes manual removal impractical or impossible, gorse can be controlled with a foliar or cut-stump application of herbicide. Triclopyr has been found the most effective in treating gorse, but several other herbicides are also effective. Consult the Pacific Northwest Pest Management Handbook for more information. All chemical treatment should always be carried out according to label directions.
Other forms of gorse control may include long-term shading out by way of conifer planting, or grazing by livestock such as goats.
More information on gorse and its control can be found here:
Lesser celandine is a short life-cycled perennial in the buttercup family, native to Europe, North Africa, and parts of the Middle East. Today, it has become widely established in eastern North America and the Pacific Northwest, as well as Japan and New Zealand. It has a low, dense, spreading growth habit and a very early growing season. Lesser celandine can be rather easy to identify, as the small, bright yellow flowers are among the first to appear on the landscape- in Lincoln County, blooming usually begins around mid-March and lasts until early to mid-April. Flowers are simple in shape, glossy, with 7 to 12 petals. The leaves are heart-shaped and glossy, dark green on the top surface and paler green underneath, and first emerge in late winter. By the end of May, foliage dies back and the plant enters a six-month dormancy phase. Lesser celandine can spread by seeds, but primarily spreads vegetatively through root tubers and above-ground stolons. It prefers growing in seasonally wet- but not waterlogged- locations.
Why is Lesser Celandine a Problem?
The early growth period of lesser celandine enables it to pre-emptively outgrow neighboring native species, spreading its root systems and crowding out other nearby plants before they have even come out of dormancy. This especially hinders the growth of ephemeral spring-flowering native wildflowers such as trillium and fawn lily, which can easily lose their short, single-season growth period to lesser celandine encroachment.
Lesser celandine’s ability to propagate from broken-off root tubers makes infestations very easy to spread via soil disturbance. Digging or tilling soil with lesser celandine tubers present will create many more individual plants, and tools or machinery with tuber-containing soil stuck to them can accidentally transport the plant to new locations. Erosion and flood events may also spread lesser celandine without human or animal interference; as such, low-lying, flood-prone areas are often more susceptible to lesser celandine infestation.
Controlling Lesser Celandine
If caught early, lesser celandine may be eradicated by hand-digging the entire plant, then bagging and disposing of it in landfill garbage. Do not attempt to shake dirt loose from removed plants- even a single small tuber can begin a new infestation if dislodged. If the infestation is larger than a few singular plants, manual control will likely not be possible and attempts at such can worsen the infestation. Solarization or mulching have not shown to be effective due to the plant’s ability to undergo long dormancy periods- infestations usually return as soon as open surfaces can be found.
Larger infestations of lesser celandine can be controlled and- if treated consistently- eradicated by foliar applications of herbicides such as glyphosate and imazapyr. Any herbicides used should only be applied in accordance with label directions.
While chemical control of lesser celandine is the most effective eradication method, application can still be tricky due to the timing of the plant’s life cycle. As foliage first emerges during winter and dies back by the end of spring, finding a window of time in which weather is suitable for foliar herbicide applications can be difficult in the Pacific Northwest’s rainy climate. The short growth window also makes it difficult to plan for effective treatment within the same year as an infestation is first noticed. As lesser celandine is a new introduction to Lincoln County, and distribution within the county is currently limited, this species is a high priority for Early Detection Rapid Response treatment. Lincoln SWCD’s licensed herbicide applicators are available to assist in treatment of this invasive plant.
If you believe you have discovered an infestation of lesser celandine, report it to Lincoln SWCD by emailing LSWCD or by phone at (541) 265-2631.
Fennel is a large, aromatic perennial herb in the carrot family, which originates from the shores of the Mediterranean Sea but is now found on all continents but Antarctica- it is especially prevalent in coastal areas. Much of this global dispersion is a result of its longstanding cultivation for culinary purposes. Fennel prefers to grow in dry, rocky, disturbed soils, and is often found on seaside bluffs or on road edges.
Mature fennel plant in South Beach, Oregon
Closeup of fennel flowers
Closeup of fennel leaf fronds
Physical Description
Fennel can easily be spotted during the late summer and early fall by its umbels of yellow flowers, growing atop hollow, greyish-green, segmented stems which can reach up to seven feet tall. The leaves are thin, threadlike, and finely branching; somewhat resembling dill. The yellow flower umbels and threadlike leaf fronds allow fennel to easily be distinguished from species such as cow parsnip, poison and water hemlock, and Queen Anne’s lace, which have white flower umbels and flat leaves. Additionally, fennel leaves have a strong licorice-like scent when crushed, unlike other plants found locally.
Why is Fennel a Problem?
With its hardy growing capabilities and prolific seed production, fennel can easily escape cultivation and disperse into the natural landscape. It can also regrow from root crown fragments, opening the possibility for introduction from fill dirt. Fennel is a prolific weed throughout most of coastal California, and in some places may be the most dominant plant species on the landscape. It is suspected that fennel produces chemicals that inhibit plants of other species from easily growing alongside it. Left uncontrolled, fennel may take over entire meadows and hillsides, edging out sensitive native flora and the fauna that depend on them.
As changing climates bring warmer and drier weather to the Oregon Coast, growing conditions for fennel are becoming more and more favorable. Recent years have seen a northward migration of the plant up from California, though populations have not yet reached the sizes and densities often seen further south. In order to get ahead of this looming issue, fennel has recently been designated as a high-priority species in our Early Detection, Rapid Response (EDRR) program. Please contact info@lincolnswcd.org for help in identification and determining if your property is eligible for this program.
Controlling Fennel
Mowing or slashing fennel before it flowers can help control infestations by preventing seed production and depleting the plant’s energy, but will not eliminate infestations as the plant will almost always regrow. Digging out the root crown will prevent regrowth, but this may be difficult or impossible due to fennel often growing in rocky soil or cracks between pavement.
Chemical control is generally considered the most effective measure for controlling fennel infestations, with foliar applications of triclopyr and/or glyphosate showing best results. Chemical applications are best done before the plant has flowered, and should always be carried out according to label directions.
More information on fennel and its control can be found here:
Purple Loosestrifeis an herbaceous perennial which grows natively in temperate regions of Europe, Asia, northern Africa, and eastern Australia. As of the present day, it has been introduced to southern Africa, North America, and South America. Introduction in North America began on the East Coast in the early 1800s, as an ornamental garden plant or as forage for European honeybees, which are highly attracted to the plant. The earliest recorded occurrence in Oregon was in 1952, in Polk County. It has now spread through most of the state, with distribution concentrated in the Willamette Valley, and occurrences still relatively sparse on the Coast.
Purple loosestrife prefers wet environments, and is typically found in wetlands, roadside ditches, retention ponds, or on river edges.
Physical Description
During the blooming season (June to September), purple loosestrife visually stands out in the landscape due to its tall flower spikes. Individual flowers are small and are usually purple, but may be pink or in rare cases, white. The stems are square and leaves are lance-shaped and oppositely arranged. Though purple loosestrife can resemble the native fireweed, the preferred habitats of each plant are usually quite different, with purple loosestrife preferring wet areas, and fireweed more often being found in dry habitats.
Close inspection of the flower spikes can help differentiate the two species. Additionally, fireweed leaves are alternately arranged, not oppositely like purple loosestrife’s.
Why is Purple Loosestrife a Problem?
With each plant producing up to 2.7 million tiny seeds annually, small infestations can rapidly become massive. These dust-like seeds mainly spread via wind or by water in the wet habitats they usually colonize. While distribution within Lincoln County is currently limited, regions where the plant has been present for longer have seen it completely overtake entire marshes, pushing out sensitive native plant and animal species. As a high-priority species in our Early Detection, Rapid Response (EDRR) program, Lincoln SWCD may be able to offer free chemical treatment for purple loosestrife. Please contact info@lincolnswcd.org or call (541) 265-2631 for help in identification and determining if your property is eligible for this program.
Controlling Purple Loosestrife
Digging up purple loosestrife is one of the more effective means of control, and can still be a feasible means of eradication in Lincoln County where infestations have not yet become a landscape-scale problem. However, care must be taken to ensure all root fragments are removed from the soil to prevent resprouting. If digging up all loosestrife plants is not possible within the year, deadheading the flower spikes before they go to seed will help curb the spread of infestations. Take care to bag any removed material and dispose of in landfill garbage.
Purple loosestrife can also effectively be controlled by herbicide application at almost any time of year. In particular, glyphosate, imazapyr, or triclopyr have been found to be most effective in controlling purple loosestrife. Care must be taken when exercising these methods due to the plant’s tendency to occur in sensitive aquatic habitats. Treatment occurring in or adjacent to wetlands, river or creek channels, or any other sensitive aquatic environments should be carried out by an applicator with an Aquatic Pesticide Applicator license. All herbicide treatments must be in accordance with label directions regardless of location.
More information on purple loosestrife and its control can be found here:
Teasel is a highly invasive plant native to Eurasia and North Africa, currently listed as a Class B noxious weed in the state of Oregon. As a biennial plant, it usually completes its life cycle in two years, and grows in a rosette form when dormant or not yet mature. Mature plants may reach 7 to 10 feet tall and are easily identified by their egg-shaped flower heads, which are up to 4 inches long, spiky, cupped by long bracts, and can dry out and persist on the plants long after the blooms have died. Blooms form in belts around the flower heads and are purple or dark pink in color. The leaves of mature plants have distinctive bumpy or prickly surfaces, oppositely-arranged and fully clasp the stem (which is also prickly).
Dry inflorescences
Fuller’s teasel inflorescence
Foliage
Why is Teasel a Problem?
Teasel, with its hundreds or thousands of individual flowers allowing each plant to produce multiple thousands of seeds, can easily form dense single-species stands where conditions are favorable, blocking out most native flora. Large, dense infestations are often seen along roadsides or waterways, indicating that transportation of seeds via flowing water, debris stuck to vehicles, and roadside mowing are likely significant dispersal methods for the plant. Infestations near waterways in particular pose a major threat to many sensitive riparian species.
Controlling Teasel
Deadheading (cutting flower heads of) teasel is one of the most effective ways of containing an existing infestation. Care should be taken to bag any cut flower heads, as the seeds held within will still readily germinate after being separated from the plant. Dispose of bagged flower heads by burning or at a landfill- do not compost. The plants are relatively short-lived, and dedicated control of seed production may eliminate or significantly reduce infestations.
Mowing is not usually an effective method of controlling teasel and will in fact worsen the infestation if flower heads are present. However, if flower heads from the previous growing season have been removed, springtime mowing when plants are just beginning to produce new flower heads can be effective. Teasel is also relatively easy to pull by hand.
When used according to label instructions, foliar applications of triclopyr or glyphosate may effectively control teasel infestations. Both chemicals are best used in early spring, before the plant has started to transition from the rosette phase to the vertical growth phase, so as to avoid allowing flower heads to develop. The next-best season for chemical application would be late fall, when the plant is drawing energy into the taproot.
Regardless of the chemical applied and season of application, it is important to understand the selected chemical and if it is allowed for use in the selected area, especially when near waterways and in areas where drips, spills and over use could contaminate surface and groundwater.
More information on teasel and its control can be found here:
Also known as artillery plant, weasel-snout, yellow Lamium, or aluminum plant, this European native wildflower was introduced to the US as an ornamental garden plant. It is a perennial groundcover plant and may exhibit upright or trailing growth habits depending on the landscape. It is an ODA B-listed noxious weed, and its sale has been banned in both Oregon and Washington.
Physical Description
The most common variety of invasive yellow archangel displays hairy, oppositely arranged, ovate (egg-shaped) leaves with scalloped margins and silvery variegation. Some varieties lack variegation and instead have uniformly green leaves. The yellow flowers are arranged in halos around the stem, giving rise to the common name "Yellow Archangel".
Why is Yellow Archangel a Problem?
Capable of growing in full shade or full sun, with patches able to grow outwards at a rate of 1 meter per year, this invasive ornamental readily outcompetes many other native groundcover plants and thrives in disturbed areas such as logging or construction sites. Yellow archangel can easily regrow from root and stem cuttings, meaning that complete eradication through mechanical removal (hand pulling, digging, mowing) is very difficult, or nearly impossible in the case of large infestations. Mowing or weed whacking in particular can actually worsen infestations, as many small plant fragments can then be easily dispersed and self-propagated into new plants.
Controlling Yellow Archangel
Yellow archangel overtaking a clearing in the Suislaw National Forest
Chemical control (i.e., herbicide spraying) is an effective mechanism for controlling yellow archangel populations, especially when combined with carefully applied manual control methods. While hand pulling may be effective for controlling small populations, provided great care is taken to ensure no root, stem, or leaf matter is left behind, sheet mulching is a better approach for denser patches. Repeated cycles of manual and/or chemical control may be needed each year to prevent a resurgence of an infestation.
More information on the yellow archangel and its control can be found on the page below:
Slender false brome is a state-listed B invasive species, native to North Africa and Eurasia. It is a perennial bunchgrass most commonly found in dry woodlands, but may also grow in open areas. The tall, tufted grass may grow up to 3 feet high and displays a nodding growth habit in both its blades and flowers. The blades are broad and flat with fine hairs on the edges and both sides of the blades, and may range from dark green to bright yellow-green in color. Stem sheaths are densely hairy, and inflorescences (seed heads) bear relatively large seeds, which are directly attached to the stem. Because this species may be difficult to distinguish from other grasses, we recommend emailing our noxious weeds program staff for positive identification.
Slender false brome
Close-up of hairy stem sheaths
Inflorescence (seed head)
Why is Slender False Brome a Problem?
Being highly shade and drought-tolerant, slender false brome can quickly outcompete native plants and establish itself as the dominant species in forest understories. It acts as excellent cover for rodents, often leading to increased populations, which in combination with the suffocating nature of established false brome thickets can severely restrict the recruitment of young native trees and shrubs, as any seedlings which manage to establish themselves in the dense grass will often be eaten by the increased rodent population. Slender false brome may also be toxic to livestock, especially sheep.
Controlling Slender False Brome
Small patches of slender false brome can effectively be controlled by hand-pulling before patches become established. This is best done in April and May, when the grass has not yet gone to seed and early spring rains moisten the soil, allowing for the weak root system to easily be dislodged. Hand-pulled patches should be monitored in the following years for signs of resprouting.
Larger patches, however, are most effectively treated through chemical means. Early summer through mid-fall is the best time for herbicide treatment, and mowing false brome patches each year in June before seeds are produced can reduce the overall amount of herbicide needed by preventing the grass from re-germinating after treatment. For advice or assistance in controlling slender false brome infestations, or to report an infestation, please contact the Lincoln Soil and Water Conservation District by calling (541) 265-2631 or by emailing Lincoln Soil and Water.
An in-depth summary of slender false brome control methods can be found in this document:
Policeman's helmet, also known as Himalayan balsam or jewelweed, is a state-listed B invasive species native to the Himalayan region of Asia. Policeman's helmet and its relatives are known for their showy flowers and ballistic seed dispersal method. It bears light pink to purple flowers and can grow up to 8 ft tall. The stems are vertically ribbed, reddish-green in color, and have red swollen nodes with small glands at the leaf base.
Policeman's helmet is becoming increasingly common in Lincoln County, with the most expansive infestations occurring along the Alsea River. Lincoln County is home to a native relative of the policeman's helmet named Touch-me-not balsam (Impatiens noli-tangeri) that is much smaller and has yellow to orange-colored flowers.
Policeman’s helmet infestation
Flowering infestation
Policeman’s helmet leaves
The glands for which Impatiens glandulifera is named
Purple flowering form
White-pink flowering form
Why Is Policeman’s Helmet a Problem?
Policemen's helmets invade early successional forests near and along riparian corridors. It has the capacity to produce as many as 2,500 seeds per plant and launch them as far as 20 feet. In appropriate conditions, a policeman's helmet will grow in dense thickets that out-compete many native species. The dense growth and sheer number of flowers that a policeman's helmet produces limit pollinator exposure for native plants as well as forage opportunities for wildlife. Policeman's helmet infestations have the potential to drastically alter habitat structure.
Controlling Policeman's Helmet
Policemen's helmet infestations are readily controlled by repeated pulling or grazing. Any of these manual control methods should occur prior to flowering to prevent the dispersal of seeds. Because stem pieces can produce new roots from their nodes, plants that have been pulled should be bagged or left to dry on pavement or a tarp before disposal.
If control methods are implemented after seed maturation, the slightest touch will cause an explosion of seeds. If the flowers go to seed, it is best to avoid control until the following spring. Since the seeds remain viable for a relatively short period (approximately 1 to 2 years), implementing control practices over 2 to 3 Springs should drastically reduce an infestation.
If persistent control methods seem to be ineffective after several years, there is most likely an infestation upstream of your property. If you find yourself in this situation, share Policeman's helmet control information with your neighbors and contact the Lincoln Soil and Water Conservation District (LSWCD).
Yellow flag iris is an aquatic invasive plant found in Lincoln County that readily impairs wetlands, rivers, and streams. These aquatic habitats are critical to numerous sensitive fish and wildlife species, which makes control of yellow flag iris particularly challenging. Yellow flag iris is classified as a State Listed B noxious weed and is considered an Early Detection Rapid Response (EDRR) species, and should be reported by emailing Lincoln Soil and Water Conservation District (LSWCD) and the Oregon Invasives Hotline. In Lincoln County, its relatively sparse presence makes it a priority species for early detection and control so as to prevent more serious infestations. The ISCP is currently inventorying infestations of yellow flag iris within rivers, streams, and wetlands throughout Lincoln County. If you know of an infestation, email our Program Manager or call (541) 265-2631.
Physical Description
Growing up to 6 feet tall, yellow flag iris is the largest iris species found in Lincoln County, towering over any other varietals and natives. It is a perennial native to Europe that was introduced as a garden plant, and a water treatment species (accumulates heavy metals) in the United States. It spreads by dislodged fragments of its underground rhizome (see photo below) or by its corky seeds, which can float. During the late spring months, its yellow flowers are a good identifier. A good place to see this species in Lincoln County is at Brian Booth State Park, formerly known as Ona Beach State Park.
Why is Yellow Flag Iris a Problem?
Yellow flag iris is a very large and aggressive species that grows quite successfully in standing water such as wetlands and streams. Its dense growth habit rapidly out-competes and excludes the native vegetation that wetland wildlife are dependent upon for food and shelter, such as sedges and rushes, while the iris itself does not provide meaningful food or shelter. In small and swift-moving streams, yellow flag iris can clog waterways and alter flow patterns, leading to flooding.
Controlling Yellow Flag Iris
Yellow flag iris is very difficult to control due to its expansive root system, which deeply penetrates the soil substrate. Removing all portions of the roots and rhizomes is necessary for manual control. But without caution, digging can lead to the spread of rhizome fragments. Herbicide application to control yellow flag iris should be conducted by a licensed applicator due to treatment occurring in and around water. If you have a yellow flag iris infestation on your property, you can help prevent its spread through the local watershed by clipping, bagging, and properly disposing of any flowers before they go to seed. Do this with caution, as the sap from this plant has the potential to cause temporary skin irritation.
Clematis vitalba is a European perennial vine introduced to the United States as an ornamental. ODA classifies clematis as a Class B noxious weed due to the significant threat it poses to native vegetation.
Clematis is able to envelop entire trees, which increases the likelihood of toppling during storms, and constricts stands of native shrubs. In Lincoln County, clematis is an Early Detection Rapid Response (EDRR) species and should be reported by emailing the Lincoln Soil and Water Conservation District (LSWCD) and the Oregon Invasives Hotline to prevent widespread establishment.
The main method of clematis introduction is wind dispersal of its seeds. Clematis aggressively climbs any vertical object, from fences, buildings, bridges, or telephone poles to trees and shrubs to increase the distance it disperses its seeds.
Why is Clematis vitalba a Problem?
Clematis vitalba during the growing season (left) and as seeds during dormancy (right)
Clematis is a plant species that rapidly establishes and readily degrades habitats into a monoculture. Clematis is able to create dense mats along the forest floor and engulf trees. It prevents the natural regeneration of annual plants and has the ability to decompose shrub stands via smothering. The extra weight clematis vines place on trees can cause them to topple over.
Controlling Clematis
The method of eradication is dependent upon the size of the infestation. Recommended control methods range from digging up roots and cutting vines to chemical control. Many considerations are site-specific. General methods of control are outlined in the link at the bottom of the page.
If you believe you have discovered an infestation of Clematis vitalba, report it to Lincoln SWCD by emailing LSWCD or by phone at (541) 265-2631.
