What Is Hawkweed: Tips For Controlling Hawkweed Plants
Native plants provide food, shelter, habitat, and a host of other benefits to their natural range. Unfortunately, the existence of introduced species can force out native plants and create environmental issues. Hawkweed (Hieracium spp.) is a good example of either a native or introduced species.
There are about 28 types of hawkweed found in North America, but only half are native varieties. What is hawkweed? This relative of chicory is a fast spreading plant with introduced species that are rapidly claiming native habitat. The plant is considered a pest, and hawkweed control is paramount in some Northwest and Canadian areas.
What is Hawkweed?
There are around 13 types of hawkweed that are native to North America. These are capable of overtaking fields in a short period of time. Recognizing the plant is imperative to controlling hawkweed species that are not native.
The plant has an attractive brightly colored dandelion-like flower that rises from a short rosette of 4- to 6-inch (10-20 cm.) long flat, narrow leaves. The leaves are covered in fine hairs, the number of which varies by species. Hawkweed stems contain a milky sap and may extend 10 to 36 inches (25-91 cm.) out from the plant. The perennial weed forms stolons, which further spread the plant.
Types of Hawkweed Invaders
The most invasive of the European species are the yellow, orange and mouse ear hawkweeds (H. pilosella). Orange hawkweed (H. aurantiacum) is the most common form of the weed in western North America. The yellow variety (H. pratense) is also referred to as meadow hawkweed, but there are also yellow devil and king devil hawkweeds.
Hawkweed control relies on early detection and persistent chemical applications. In fields, the plant quickly crowds out native species, which makes controlling hawkweed important in affected areas.
How to Get Rid of Hawkweeds
Hawkweed can escape cultivation and infest fields, ditches and open areas. The plant’s stolens spread out and create daughter plants, spreading rapidly in a mat of greenery that disrupts natural plantings.
Controlling hawkweeds that are random and scattered is easily done by digging out the entire plant and roots. Hawkweed control gets trickier when it has been allowed to spread. For serious infestations, chemicals are recommended. Selective herbicides applied according to the manufacturer’s instructions in early spring, can knock out the young plants.
Controlling hawkweed with fertilizer applications in spring increases grasses and other ground covers to help choke out the weed.
New Biological Hawkweed Control
The organic gardener tries not to use any herbicides or chemicals in the landscape. In order to get some help controlling weed pests, new trials in biological warfare on problem plants are being studied. Studies in which insects eat this plant are being conducted and, once the primary predators are identified, they will be monitored to ensure their presence doesn’t have a negative effect on other plants.
This is a time consuming process but bio-control on other pest species has been very effective and safe. For now, a combination of fertilization, manual control and spot chemical application on hawkweed, provide the best method of managing this pest plant.
Note: Any recommendations pertaining to the use of chemicals are for informational purposes only. Chemical control should only be used as a last resort, as organic approaches are safer and more environmentally friendly
Hawkweed in the lawn
Q: I am having a very hard time getting rid of a weed that has popped up in my lawn this year. It's a new lawn in its second year. I have searched many sites trying to identify it and the closest thing is hawkweed. Can you recommend how to get this under control? I have used Weed and Feed on the area but it hasn't helped.
A: Hawkweed is a pretty common weed around here, it's up and growing already, and it's one that's pretty adept at invading new or thin lawns. One good identifying factor is that the stems ooze a milky liquid when you snap them.
This is a perennial weed (comes back year after year), and it spreads both by seeds and runners, which makes it double trouble. If you've only got a few, hawkweed plants are fairly shallow-rooted and easy to dig up with a screwdriver or similar weeding tool. If you've got a bunch, granular weed-and-feed products usually do a decent job of controlling them.
If that hasn't worked, I'd suggest hitting them with a liquid broadleaf weed control labeled for use in lawns. Ortho's Weed B Gon is the best known, but all garden centers, home centers and hardware stores should have at least one of these. The liquid can be directed right into the patch and it sticks better than granules. These products won't hurt the surrounding grass.
If your hawkweeds aren't dead in 10 days or so, you can hit them again. And if that doesn't do it, I'd be getting real tough with one of those flame weeding torches that some catalogs offer. Either that or give up and tell people you're starting a hawkweed garden. The orange or yellow flowers are actually pretty nice in summer.
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Hieracium aurantiacum (Orange Hawkweed)
Pick an image for a larger view. See the glossary for icon descriptions.
Compact cluster of 5 or more dandelion-like flowers on short hairy stalks at the top of the plant. Flowers are ¾ to 1 inch across, deep red-orange to orange to yellow-orange, often fading to yellow in the center. The bracts behind the flower are densely covered in glandular hairs.
Leaves and stem:
Leaves mostly surround the base of the plant, 2 to 5 inches long and to 1 inch wide, pointed or rounded at the tip, and toothless. 1 or 2 small leaves may also be alternately attached on the lower stem. The leaves and stem are both covered in long hairs.
Fruit is a dark seed with a tuft of white hair to carry it off in the wind.
Orange Hawkweed is highly invasive, the largest infestations being in the counties around Duluth, where it first arrived in Minnesota. It has since been spreading south and west, and is likely very under-reported in the state. Large mono-cultures can be seen along roadsides into Aitkin county, at least. When not in bloom it resembles Meadow Hawkweed (Hieracium caespitosum), and often is found growing with it and its cousin Glaucous King-devil (Hieracium piloselloides).
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Photos by K. Chayka taken at Wild River State Park, Chisago County. Photos courtesy Peter M. Dziuk taken in Anoka and Pine counties
Have you seen this plant in Minnesota, or have any other comments about it?
A field recently sprung up due to lack of mowing off cty 8 south of MN 27 about 6 blocks west side of road.
Near the National Monument. I thought the bloom was very interesting and dramatic in color shading.
Yes, Sharon, that is the case with many invasive species. Non-native plants are brought here and cultivated because of some value to humans, often their aesthetics. Then they escape into the wild and proliferate uncontrolled due to lack of natural predators. In some spots of NE MN the masses of orange hawkweed seemingly go on forever. Pretty maybe, but devastating to the natural order of things. :-(
In a field just outside of town. I have been photographing it every day. It's lovely.
Donna, I will just say that beauty is in the eye of the beholder. I can't see something like orange hawkweed as anything but an evil weed when I see it take over entire fields. :( We spotted a few plants in one of our favorite natural areas today. How long before it takes over, I can't say, but I do know that it will spread, and rapidly.
Just found a new small patch of these guys in Shakopee. Yanking them out for sure.
I have had, for years a few plants in my yard, I suppose they were controlled by mowing. I am trying to convert the edge of my yard to native prairie and now I have a lot of it. Still not as big of problem as the bluegrass but still a problem. Sounds like I need some Round Up. Gary
Photographed it, thinking it was Indian Paintbrush. Fall 2010.
Field of it at the Eli Wirtanen Historic Finnish Farmstead. I took lots of pictures because there were also a lot of butterflies in that field. Then I go to your site for an ID of the flowers. Kind of disappointed now :(
Found lots and lots of Orange Hawkweed in NE Minnesota this June, 2011, all along the Superior shore line and inland.
Large stand along Highway 1 east of Effie photographed in late June.
This is a horrible weed that has created a mat covering the lawn area of my property in Lake County. Mowing has actually encouraged its spread and it has crowded out the wild strawberries that once thrived there. A tip given to me by Michael Lynch the Invasive Species Coordinator of Cook County was to use fertilizer since this plant likes the thinner poor soils of North East Minnesota. I have also seen it growing on a friend's property in Columbus (Anoka Co).
This stuff just popped up in our front lawn in SW Mpls. I'd not seen it before and came to look it up. It is pretty, but it won't be for long now that I know its status. Thanks for the tips for eradication.
Started noticing these plants all over my father's lake property the last few years but we did not know what they were until I came to your website today. Love the colors I even tried transplanting this in my garden at home but thank goodness it died! Did not realize they were an invasive noxious weed!
Saw this today along the road in Rum River State Forest (South unit). Only a couple of plants, took some seeds. Would have pulled them had I known. Destroying seeds.
We have a small area of our large, rather wild yard (about an acre) that has several hawkweed plants. They are attractive, and do not seem to be spreading, so I was surprised to see that they are invasive.
The grass hay fields are completely orange this year!
This came in my yard in 2013. Only have a few this year. We now l have another yellow type.
We have been trying to establish a natural prairie area on several areas of our property and just discovered the orange hawkweed growing in a small area. We thought it was beautiful and were excited that some wildflowers were establishing themselves. So disappointed!
We have some growing in our mowed "lawn" area on our land just north of Solway. Killing some of the other species out. How do we get rid of it.
These are growing in open woods on our property located on a small island on Lake Vermilion.
It's next to the bathrooms and campsites and Crescent Lake on the north shore!
found it along our dirt road blooming today 6/20/16 in front of our lilacs about a dozen plants.
Found this in my garden. Thought it was pretty until I found it here. I will be getting rid of it right away!
I saw this east of grand rapids. this year I see it in bemidji. but doesn't it have some use?
The non-native, invasive hawkweeds have no use, at least none that haven't been filled by native species for thousands of years. The invasive hawkweeds degrade natural habitats and decrease biodiversity. That's not beneficial to any of our native insects or other wildlife.
We just moved onto our property last fall and noticed these beautiful noxious weed early this summer. I just love the colors but I am disappointed that I can't even find a way to use these beauties as a beneficial holistic plant. I just pray that they don't take over our entire yard!
This wildflower is rife in our area, west of Sandstone. Seems more prolific this year, especially, as are the oxeye daisies.
Was really excited to see these beautiful flowers in areas around my pond, but just discovered it's an invasive weed. How disappointing. Also saw an abundance of them along our MS150 bike route last weekend traveling south from Duluth.
I was getting ready to transplant these little beauties from the lake side of the house to an area set aside for wild flowers, but thanks to you I'm going out to start the mower. Thanks!
Found on Rock Lake shoreline in Becker County, MN on 6/23/16.
Found a little bunch of these flowers . Maybe 30 of them in the group
I have a field approximately 350' x 150' filling up with the orange flowers. Any suggestions on how to get rid of it without breaking the bank?
Found today in the backyard
I found 10 plants blooming in my backyard this evening. Is it easy to eliminate?
LN, pull them out now. Never let them go to seed.
We have both the orange hawk weed and the yellow. Is it to late to apply chemical since the plants have already flowered?
Jerry, do whatever you have to to prevent these plants from going to seed!
I've had acres of these little beauties thinking they were Indian Paintbrush. At times they will appear as an orange carpet raised above the lawn undulating with a slight breeze, which is a cool sight to see. But, I now realize (thanks to your webpage) that they are an invasive species, and will "stem" their propagation next year. This year I had about a half acre of these wild beauties.
I seen this in long prairie mn. It is actually a large patch behind my grandparents house. Is this plant native or non native? I am having trouble telling it has oval leave like basil herb plants at the base. It's tall one stem with multiple flower bud heads at top and fuzzy stem. It look like the invasive kind of plant.
They were all along the side of highway 35 just south of Sandstone.
Saw several individual plants of orange hawkweed, Oct. 16 2017 while visiting the area. All were sighted upslope of the trail. Given its agressiveness, there are probably lots more.
The beautiful orange and yellow color caught my eye in the middle of my yard. Looked them up on Google. Soo sad to learn what they truly are.
Found in my large yard in Orock Township. Took pictures of it to see if it was evasive or not. Now I'll have to eradicate this plant like a couple other ones I've found over the years.
First found a couple of plants along the north side, shaded foundation of our newly constructed home. Thinking how beautiful they are I kept begging my husband not to weed whack them, along with the little wild ferns. He would do so anyway, lol. I checked and every year the flowers cone back. Fast forward sixteen years later and I am pretty sure I have found quite a few more plants spread throughout the backyard. Also, what we call Creeping Charlie has totally taken over the back and side yard. I see that you are suggesting to pull it out by hand and then fertilize? That is a lot of pulling! I briefly spoke to a gentleman in passing. He said something about planting buckwheat, or something like it to kill off the Creeping Charlie. Is there anything to that notion?
Finally able to mow our lawn in over 2 weeks. While mowing today I came across the 6вЂ™ patch of orange flowers and took pictures to identify later. As they were in the middle of the acre I mow, I mowed them over, along with my creeping charlie thatвЂ™s tucked in 20вЂ™ patches around the yard now. If I donвЂ™t mind them being in the yard, and I keep mowing them down, I assume I can just leave them be? We have free range chickens and we donвЂ™t use chemicals on the lawn.
Teresa, they can still flower and set seed after being mowed over so they will likely still spread.
Dense population on property edge where neighbor scraped the vegetation off in a misguided effort to control poison ivy. Seems as if they are edging the poison ivy out.
Found the first of it in our field in 2016 SE of Brainerd. Found it while walking our fields with a NRSC agent. He didn't seem to know what it was and definitely did not know it was noxious and that it spread so quickly. If he had told me to get rid of it back then I probably would not have it everywhere now. We are going to use a herbicide to kill it, hopefully once and for all, but probably going to be more of a maintenance issue now. Seven acres of hay fields and a yard full of it.
These popped up in around some grassy shrubs in our yard. I thought they were pretty, but seeing how fast they've multipled, I was nervous they were a noxious weed. Glad I looked into it. They are being pulled up immediately!
Large cluster of this plant didnвЂ™t realize they were invasive.
Appeared for first time today in an area that was logged off in 2012. Very pretty. Are they pollinator friendly?
On the ten Acres of Larry KlinerвЂ™s вЂњWoodland AcresвЂќ They are through out our woods both the yellow and orange variety.
We have this growing in the ditches along County Road 43 in Benton County. It is creeping up driveways and making its way into lawns. Spreads very quickly and aggressively.
Just found a couple plants yesterday on property I bought NW of Milaca. I thought they were pretty, until I found out what they are! I will be pulling them.
Found some growing near one of the pump houses (maintained by the city) during a walk.
Just noticed them in my grove of black walnuts as I was mowing. Stopped and took some pictures, they certainly are pretty. First time I've even seen them. Initially felt a bit sad that I then mowed them down. Probably will hit the area with Round Up when I see them return, and hope the grass spreads back into the treated area.
Started growing in my yard, they spread fast! When I found out what it was, round-up did the trick!
I found a large section of grass taken over by these. I thought they were another flower. after it rained I pulled them all out by the roots. now I am on the lookout and dig them right away. we are in Maplewood - Ramsey County. thank you for this great information. Mary
Saw some in a pasture 8 miles west of city of Isanti, south of CR5 about 1/2 mile, east side of Zuni Street NW.
MASTER GARDENERS: Hawkweed a very hawkish weed indeed
Have you noticed a yellow or orange bloom on a tall stem that looks like a dandelion on stilts? Many I talk to have noticed this plant in places where they did not appear before. In the woods, along trails, in forage fields, in yards, and especially in ditches and un-maintained properties. I understand why many find the golden or orange fields attractive. You might find yourself humming “Fields of Gold” by Sting.
Called narrow leaf hawkweed or northern hawkweed, its scientific name is Hieracium canadense, but don’t blame the Canadians for this one it grows all over the world. In Minnesota, it is found everywhere except the southwest part of the state. The Minnesota Department of Natural Resources lists orange hawkweed (Hieracium aurantiacum) as an invasive terrestrial plant. In all, there are more than 50 varieties of the plant.
One of the reasons that hawkweed is so successful at invading new territory is that it spreads by seeds, by runners and by root buds. There is also evidence that it is allopathic, that it chemically suppresses adjacent plants. It is interesting to see how quickly the plant invades new territory.
In Wisconsin, it is listed as a plant that reduces the quality of forage crops while in British Columbia it has become recognized as a serious invasive. In Washington state, hawkweed must be removed from all property. What is ironic is that you can go on Amazon and find more than 20 sources of seed, some describing it as a “spectacular ground cover.” Go figure!
Control of hawkweed can be a tricky business. To get rid of a few plants that have invaded your lawn or garden, digging it up and making sure you get all the root is the most effective method. I have tried mowing it in a road ditch and find that it does not slow it at all. In fact the plant simply shoots up a short bloom stem and goes to seed as well as reproducing more rapidly vegetatively. Seeds are easily transported on the wind and by birds. It colonizes especially well on disturbed sites such as openings created when utility work is done in roadside ditches.
An alternative method of control where it has invaded grassy areas is to fertilize heavily to encourage the grass to grow densely and crowd out the weeds. I have tried flame weeding to no avail. What is left is chemical control with a selective herbicide. In Washington state, their DNR recommends Dicamba with repeat applications. They note that 2,4-D does not provide effective control and glyphosate kills grasses as well and opens the door to re-infestation. Minnesota still recommends that the “most effective control is with Clopyralid or 2,4-D in the rosette stage. A surfactant should be added to the mix to ensure adherence of herbicide to the hairy leaf. These products are dangerous chemicals. Use safety precautions to avoid exposure to yourself, others, pets, wildlife, the surrounding environment or call a certified professional.
The responsibility to deal with invasive and noxious weeds in a safe manner lies with the landowner in Minnesota. The Department of Natural Resources has online guides to help with identification as well as a printed Trail Ambassador’s Guide. For more information, visit www.mndnr.gov/invasives, putting Hieracium aurantiacum in the search box.
Learn to identify the plants you see around you. Many have an interesting history and are very beneficial while some like hawkweed belong on a “wanted” poster.
Weed class: B
Year Listed: 2014
Native to: varies by species and hybrid
Is this Weed Toxic?:
This plant is also on the Washington State quarantine list. It is prohibited to transport, buy, sell, offer for sale, or distribute plants or plant parts of quarantined species into or within the state of Washington or to sell, offer for sale, or distribute seed packets of seed, flower seed blends, or wildflower mixes of quarantined species into or within the state of Washington. Please see WAC 16-752 for more information on the quarantine list. For questions about the quarantine list, contact the Washington State Department of Agriculture's Plant Services Program at (360) 902-1874 or email [email protected]
Why Is It a Noxious Weed?
These nonnative hawkweed species and hybrids are invasive, spread readily, and have negative impacts to rangeland and other habitats, especially in mid to upper elevations and in areas with low fertility soils.
How would I identify it?
Perennial, herbaceous plants that exude a milky sap when broken, have various types of hairs, and flowerheads of yellow flowers. Nonnative hawkweed species can be difficult to tell apart, especially if they hybridize. Nonnative yellow flowered hawkweeds are grouped into two Class B noxious weed listings by subgenus Pilosella and subgenus Hieracium. Nonnative hawkweeds in the wall (Hieracium) subgenus include: European (Hieracium sabaudum), smooth (H. laevigatum), common (H. lachenalii), polar (H. atratum), spotted (H. maculatum), and wall (H. murorum).
Flowerheads are composed of all yellow ray flowers (dandelion-like). Bracts at base of flowerheads have various types of hairs. Flowerheads are generally in clusters.
Plants in this subgenus typically have basal leaves and stem leaves. Leaf edges are toothed or lobed.
In general, species in this subgenus do not have stolons.
Fruit Seed Description
Seeds are small, with ribs or grooves and have bristles on one end.
May Be Confused With
Nonnative yellow flowered hawkweeds in the subgenus Pilosella (meadow). In general, in the subgenus Pilosella (meadow), species have stolons, have no or few stem leaves and leaf edges are smooth or minutely toothed. While in the Hieracium (wall) subgenus, species generally do not have stolons, have stem leaves, and leaf edges are toothed or lobed. This listing excludes the native yellow flowered hawkweed species in this subgenus: narrow-leaved hawkweed (Hieracium umbellatum). Overall, native hawkweed species are excluded from the state noxious weed list, this includes: long-beaked hawkweed (Hieracium longiberbe), slender hawkweed (H. triste), white-flowered hawkweed (Hieracium albiflorum) and woollyweed (Hieracium scouleri).
Where does it grow?
Typically found in fields, meadows, pastures, forest clearings and disturbed areas such as roadsides and abandoned farmland. Please click here to view a county level distribution map of nonnative hawkweed species and hybrids of the wall subgenus in Washington.
How Does it Reproduce?
Plants in the wall subgenus primarily reproduce by seed.
How Do I Control It?
General Control Strategy
A long-term management strategy is needed to control invasive hawkweeds that promotes the establishment and growth of grasses and desirable plants. Make sure to monitor the area where the plants were removed for respouting roots and seedlings.
Mechanically controlling hawkweed species can be difficult to do in pastures and rangelands. Mowing plants to get rid of flowerheads only stimulates vegetative growth. If there are only a few plants, hand digging is a feasible option, but all of the roots must be removed. Once plants are dug up, put them into a city yard waste container or throw them in the trash. Do not put pulled plants in home compost piles as they might not get hot enough to kill them, and many species can vegetatively spread.
Adding fertilizer and managing soil fertility has been used to effectively control hawkweed species in some areas, especially where populations are small or new.
Control of non-native hawkweeds infestations have relied extensively on selective herbicides, which can be effective, but reinvasion can occur unless other plants can fill the gaps left by the hawkweed removal. Please refer to the PNW Weed Management Handbook, or contact your county noxious weed coordinator.
Don’t be fooled by their dainty flowers and vibrant colours invasive plants are anything but innocent! According to the Invasive Species Council of British Columbia, these aggressive plants can “permanently alter ecosystems, reduce property values, impact natural resource sectors of the economy, and in the worst case, cause the extinction of native species.”
Far away from natural predators and pathogens, these alien plants, which have made their way one way or another from their native area to BC, tend to multiply rapidly and wreak havoc on BC’s vulnerable landscape. To protect the local flora and fauna, it’s crucial to identify the “invaders” and effectively eliminate them.
Here are BC’s most “unwanted” plants to seek out and eradicate.
Giant Hogweed (Heracleum mantegazzianum)
Adorned with white flowers and huge jagged-edged leaves, the Giant Hogweed shoots up to a towering height of five metres (16 ft.) This plant dominates the Lower Mainland, eastern parts of Vancouver Island, the Gulf Islands, and parts of the Kootenays.
The sap of the Giant Hogweed is extremely dangerous when touched. Rashes and blistering can persist for up to 10 years(!) after contact, while contact with eyes results in temporary or permanent blindness.
To remove the hogweed, a professional is highly recommended. If you must do it yourself, wear eye protection and waterproof gloves and gear at all times when removing flower heads and cutting root crowns. Do not touch your skin with the gloves and clean or dispose of them afterward.
Common Tansy (Tanacetum vulgare)
With 20-200 flower heads, the Common Tansy boasts vibrant yellow petals and stems as high as 1.8 metres (6 ft.). It is widely distributed across the province, but is particularly prominent on the southeast coast of Vancouver Island, Squamish/Pemberton, Gulf Islands, Sunshine Coast, Bulkley-Nechako, Central and East Kootenay, Columbia-Shuswap, North Okanagan Regional Districts, Greater Vancouver, and the Fraser Valley.
Considered noxious by the Weed Control Act, infestations of the common tansy can be toxic for farm animals. They can also displace native plants.
Be warned: Occasional mowing will only trigger an increase in plant growth. You must use both herbicide and mowing to effectively eradicate the Common Tansy.
Spotted and Diffuse Knapweed (Centaurea biebersteinii and Centaurea diffusa)
Labelled noxious under the BC Weed Control Act, Spotted and Diffuse Knapweeds negatively transform the landscapes of the Omineca, Peace River, Kootenay, Okanagan, Thompson and Cariboo regions.
Spotted Knapweed possesses purple or white flowers with black tipped flower head bracts, while the diffuse knapweed have white, rose-purple or lavender blossoms in clusters.
Knapweeds intensify erosion and runoff, and displace native plants. When dead, its materials increase the chance of wild fires.
Eliminate the plant by hand pulling, cutting or mowing. Remove all roots to prevent regrowth and revisit the spot every so often to avert further growth.
Yellow and Orange Hawkweeds (Hieracium spp.)
Rapidly spreading throughout the eastern and western BC, invasive Hawkweeds are threatening the forest regions of the Northern Rockies, the Peace River Regional Districts and the eastern regions of the Rocky Mountains.
While the majority of Hawkweeds have bright-yellow blossoms, the only Hawkweed identified as noxious by the Weed Control Act is vibrantly orange. The Orange Hawkweed dominates the East Kootenay, Central Kootenay, Thompson-Nicola, Bulkley Nechako, Cariboo Regional Districts and Columbia-Shuswap.
Menaces to both the forest and livestock industry, Hawkweeds displace native plants, reduce forage, and invade undisturbed natural areas.
To get rid of small infestations, dig out the flower and its roots, but ensure that none of the plant parts scatter as they can easily regrow from these fragments.
Japanese Knotweed (Fallopia japonica)
Capable of growing through house foundations and cement, the Japanese Knotweed possesses stout reddish-brown stems, rough heart-shaped leaves and seasonal greenish-white flowers. Its favourite hangouts include roadsides, waste sites, wooded areas and waterways in the lower Fraser Valley region.
A born survivor, this plant can grow up to 3 metres (10 ft.) in a year and can worm its way into new territories simply with root fragments. It clogs waterways and deteriorates native plant communities.
To eradicate the Japanese Knotweed, you must remove existing stems, cover the area with plastic tarps during the fall and, finally, dig up rhizomes to prevent further growth. Since it will not compost properly, this knotweed must be bagged and buried deep in a landfill.
Scotch Broom (Cytisus scoparius)
Reaching as high as 3 metres (10ft.), the Scotch Broom can be recognized by its ridged green or brownish green stems, and vivid yellow flowers. It flourishes in sandy soils, haunting the terrains of Vancouver Island, Queen Charlotte Islands, the southern interior and the Lower Mainland.
The Scotch Broom releases toxic substances into its surroundings, restraining the growth of native plants and causing seasonal allergies. It establishes menacing colonies and hinders the activities of large animals. The worst part? Each pod contains 3 to 12 seeds, seeds that can survive over 30 years!
Eliminate the Scotch Broom by removing it before the flowering stage. Hand-pull the smaller ones and keep your eyes on the area every so often. For deep-rooted plants, remove with large tools, such as a shovel or gas-powered or hand saw.
Yellow Flag Iris (Iris pseudacorus)
From 40 to 150 cm tall, the Yellow Flag-iris is distinguished by bold yellow flowers and long erect leaves. This species is generally located along riverbanks, marshes, and lakes in southern parts of BC.
The Yellow Flag-iris does not only reduce water flow, but also displaces native plants, consequently damaging the wildlife habitat. What’s more, the rhizomes are poisonous when ingested by cattle.
The most effective technique to eradicate this species is hand-pulling or cutting for a number of years until it is completely removed. Since its leaves and rhizomes lead to skin irritation, it’s vital that you wear gloves and protective clothing. Do not compost always throw it away as garbage.