Fireweed is a stubborn perennial weed that can quickly take over gardens, lawns, pastures, and fields if left uncontrolled. With its tall pinkish-purple blooms on spike-like racemes, fireweed may look innocuous but it’s an aggressive spreader that’s difficult to eradicate.
While herbicides often provide the most effective control, fireweed can also be managed through manual removal, mowing, or mulching before it goes to seed. Eliminating this invasive plant takes patience, persistence, and using a combination of methods
What is Fireweed?
Also called rosebay willowherb, fireweed is a cool season perennial native to northern regions of Europe, Asia, and North America. It thrives in disturbed soils and spreads rapidly from seeds and an extensive underground system of rhizomes.
Fireweed grows upright to over 3 feet tall with elongated lance-shaped leaves. Starting from the bottom up, showy pinkish purple flowers bloom in late spring through summer on tall spikes. By fall fireweed goes to seed producing thousands of tiny parachute-like seeds easily dispersed by wind.
Left uncontrolled, dense stands of fireweed will dominate an area crowding out grasses, wildflowers, and crops. It’s especially problematic in pastures, hay fields, orchards, forests, and gardens.
Why Fireweed is Hard to Control
What makes fireweed so difficult to manage are the following characteristics:
- Root fragments left behind readily generate new plants
- Seeds can remain viable in soil for many years
- Each plant can disperse over 80,000 windborne seeds
- Grows vigorously in poor, disturbed soils
- Adapts to mowing by regrowing rapidly from the base
Successfully controlling fireweed requires preventing seed production and root/shoot regrowth using integrated management methods.
Manual Removal Techniques
Manual weed control techniques like hand pulling, hoeing, mowing, and mulching can suppress fireweed spread but rarely achieve full eradication.
Hand Pulling
Grasping fireweed stems near the base and gently pulling to remove as much of the root system as possible can eliminate young plants. Take care to remove all root fragments which can resprout if left behind.
Pulling by hand works best when soil is moist and should be done before flowering and seed set. Wear sturdy gloves and long sleeves when hand pulling to prevent skin irritation from fireweed’s hairy stems and leaves.
Hoeing
Using a sharp hoe to slice fireweed stems 1-2 inches below ground severs roots to starve the plant. Frequent disturbance by hoeing also exposes remaining root fragments to dry out.
Persistently monitor and remove regrowth from any missed root sections by repeating hoeing as new shoots appear. Avoid overly deep or aggressive cultivation which can spread roots.
Mowing
Frequent mowing to a low height can prevent seed production. Mow fireweed after flower bud stage and repeat every 2-3 weeks through fall to continually cut back growth. This suppresses but won’t kill established plants.
Collect and dispose of clippings after mowing to remove cuttings that may root if left on the ground. Make sure mower blades are sharp for clean cutting rather than tearing stems.
Mulching
Mulching is an effective way to smother young fireweed plants and restrict regrowth of existing weeds. Apply 4-6 inches of organic mulch materials like wood chips, shredded bark, compost, or yard waste.
Overlap the diameter of plant stems by several inches to thoroughly block light from reaching emerging growth underneath. Replenish mulch as needed since fireweed may continue to push through. Avoid using plastic sheeting as this won’t suppress underground root or shoot growth.
Herbicide Use for Fireweed Control
While labor intensive, the manual and mulching methods above can help suppress light infestations. However, for heavy fireweed invasion, herbicide application is usually the most effective option for complete control.
Several broadleaf weed killers can be used for selective fireweed management in lawns and pastures:
- 2,4-D amine formulations (many brand names)
- Dicamba products like Banvel, Oracle
- Triclopyr plus fluroxypyr like Confront
- MCPA plus fluroxypyr plus dicamba formulations
For best results:
- Treat younger, actively growing plants before flowering.
- Thoroughly wet all leaves and stems but avoid runoff.
- 2,4-D and dicamba don’t kill roots so re-treatment is needed on regrowth.
- Triclopyr and MCPA combinations give longer lasting control.
- When using any chemical control, carefully follow label directions for correct dosage, timing, and required safety precautions.
In areas where herbicide use is undesirable, non-selective glyphosate products like Roundup can be carefully spot sprayed onto individual plants or wiped onto leaves avoiding contact with wanted vegetation.
Ongoing Prevention is Vital
Eliminating fireweed takes persistence over multiple seasons. After removal, focus on stewarding the landscape to prevent reinfestation:
- Maintain healthy plant, lawn, and pasture areas to outcompete weeds.
- Avoid excess soil disturbance that favors fireweed germination.
- Quickly treat patchy areas before fireweed takes hold.
- Monitor regularly and remove young plants before they spread.
With dedication to control and prevention methods, fireweed can be successfully managed for the long term. Don’t allow this stubborn perennial weed to ever gain a foothold in your landscape again.
Key Takeaways
- Fireweed is an aggressive perennial weed easily spread by seeds and underground rhizomes.
- Manual removal provides suppression but herbicide treatment is typically needed for full control.
- Prevention after elimination is key to keep fireweed from returning.
- Use integrated management methods and persistence to fully eradicate from your landscape.
Controlling invasive fireweed takes commitment, but with diligence and patience you can reclaim your yard, fields, and garden areas for good!
What does it look like?
Fireweed is an annual or biennial herb 10–60 cm tall. It is erect with many branches. Flowering is mostly from spring to autumn but times vary for different parts of NSW. All stages of the plant from seedlings to flowering may be present at any time of year in some locations. Flushes of seedlings appear after rain in warm weather.
- bright green
- fleshy and narrow
- 2–7 cm long and 3–10 mm wide
- smooth, toothed or lobed on the edges
- stalkless and clasped around the stem
- alternate along the stems.
- small, yellow and daisy-like with up to 15 petals
- 1–2 cm in diameter
- in clusters at the ends of branches
- emerging from a small cup of modified leaves called bracts (usually 21 bracts)
- more abundant on some plants than others and up to 200 per plant.
- small and light
- 1–3 mm long
- cylindrical in shape
- downy on the surface
- attached to fine, white feathery hairs that aid in dispersal by wind.
- fibrous
- 10–20 cm deep
- branched from a central taproot.
Variable groundsel (Senecio pinnatifolius) is sometimes confused with fireweed. It’s a native Australian plant, not considered a weed. Often it grows in places where fireweed is unlikely to be, such as bushland and undisturbed sites.
How does this weed affect you?
Fireweed invades pastures and disturbed areas. It:
- reduces productivity
- is poisonous to livestock and can cause death
- is difficult to control.
Fireweed contains chemicals called pyrrolizidine alkaloids. Livestock that eat it get liver damage. The damage is irreversible and gets worse the more fireweed an animal eats. Hay, silage or grain contaminated with fireweed plants or seeds can poison livestock. Identifying fireweed poisoning is difficult. If you think you have affected animals contact your vet.
Cattle are usually reluctant to eat fireweed. Young, hungry or new stock not familiar with fireweed are more likely to eat it. Cattle can lose weight, or their growth slows. Some develop brain damage, which can show as confusion and poor coordination. Sudden death can happen in fat cattle that have eaten fireweed in the last 3 to 6 months.
Sheep and goats are more inclined to eat fireweed than cattle. They are also up to 20 times more tolerant of its toxins. Merinos tend to eat less fireweed, other sheep breeds can eat it to excess. Sheep that eat fireweed over two or more years may become unwell or die suddenly. Sheep and goats rarely show signs of brain damage.
Fireweed can poison alpacas too, but less is known about the effects on them.
Horses have more problems with fireweed poisoning. Unpigmented skin can become sensitive to sunlight, redden and peel away. Brain damage is common. Symptoms can include: dullness, aimless wandering, an uncoordinated gait, pressing up against fences, gates or trees and possible blindness.
How to safely dispose of Fireweed
FAQ
What is the best way to kill fireweed?
Options for effective control include:
Chemical options such as Bromicide 200 (WHP 8 weeks), Minder, Grazon Extra or Hot Shot for Fireweed plants at various stages of plant growth. Consult with local Norco Agronomist or sales team member to find the most suitable chemical fit.
Should I remove fireweed?
Control willowherb/fireweed in your garden. Willowherb, or fireweed, Chamerion angustifolium, is a pretty plant that looks at home in a wild garden, but will take over any domestic garden, spreading by seed and tough underground roots. Left unchecked, it will invade the space of other plants and restrict their growth.
Is fireweed poisonous to touch?
Fireweed is safe: No evidence of toxicity in humans, just mild stomach discomfort if ingested. Rare allergies possible: Watch for skin or respiratory reactions in kids. Education is key: Teach kids plant safety and spread accurate Fireweed information.
Is fireweed an invasive plant?
Fireweed, Senecio madagascariensis, is an toxic, invasive plant that occurs in Australia, South America, Africa and Hawaii.
What is fireweed & how do I get rid of it?
Fireweed is a cool-season plant that grows in the top thatch layer of your grass, as opposed to growing in the soil, which makes it more difficult to control. Pre-emergent herbicides that seep into the soil to eliminate soil rooted weeds are not an effective solution.
What happens if livestock eats fireweed?
is difficult to control. Fireweed contains chemicals called pyrrolizidine alkaloids. Livestock that eat it get liver damage. The damage is irreversible and gets worse the more fireweed an animal eats. Hay, silage or grain contaminated with fireweed plants or seeds can poison livestock.
How do I keep fireweed from taking over my land?
By implementing a combination of control methods and staying vigilant, you can keep this pesky weed from taking over your land. It is important to note that direct contact with fireweed can cause symptoms like skin irritation and redness. If you come into contact with fireweed, wash the affected area thoroughly and avoid rubbing or scratching it.
Is Fireweed A weed?
Although some varieties of Fireweed produce beautiful, vivid flowers, it is an un-welcomed addition to residential lawns. Fireweed is more difficult to control than broadleaf and grassy weeds. The roots of the Fireweed plant do not stretch down into the soil. Instead, the plant grows exclusively in the thatch layer.
How do you control fireweed in Sydney?
Pasture improvement to control fireweed is proven to work best north of Sydney where there’s more rain in summer). South of Sydney it rains more in winter and pastures are slower to establish. Selective herbicides may be needed to control fireweed until pastures mature.
What makes fireweed so difficult to manage?
What makes fireweed so difficult to manage are the following characteristics: Controlling fireweed requires stopping seed production and root/shoot regrowth using a combination of methods. Manual weed control methods like hand pulling, hoeing, and mowing provide fireweed suppression but rarely full eradication.