Is dog fennel edible

Managing Dogfennel Weeds: Learn About Controlling Dogfennel Plants

Weeds are a part of life for gardeners and homeowners everywhere, but that doesn’t mean we have to like them. Fuzzy and noxious, dogfennel is a weed to be reckoned with. If you’ve got this pest plant hanging around your garden or poking up through your lawn, you’ve got plenty of options for control. Dogfennel is an especially troublesome perennial weed that can be very challenging to control, that’s why we’ve put together this short article on managing it in home landscapes and lawns.

What is Dogfennel?

Dogfennel weeds (Eupatorium capillifolium) are common sights in the southeastern United States, frequently overrunning pastures, popping up through thin turf and sprouting in otherwise manicured landscapes. These tall weeds are easy to identify by their thick, furry stems and lace-like foliage. As they grow to heights of six feet or more, the stems may toughen into a woody base.

Dogfennal weeds are easy to confuse with similar-looking weeds like mayweed chamomile (Anthemis cotula), pineapple weed (Matricaria matricarioides) and horseweed (Conyza canadensis). When you crush the leaves of dogfennel, though, you’re left with no doubt – true dogfennel leaves emit a distinctive odor that has been described as both sour and musty.

Dogfennel Weed Control

Controlling dogfennel plants can be challenging, especially when they’re heavily established. If you can mow the plants while they’re small and keep them short, you may be able to exhaust them before they reproduce. Bear in mind that some dogfennel plants will try to reproduce at around six inches, so you’ll have to mow them close to the ground.

If you’re considering dogfennel removal in established landscape, digging their matted root system may be your best bet. A careful and dedicated digging can get most of the plants and remove their potential for reproduction, but you may have to keep at your efforts for several years as the seeds sprout and die. Since dogfennel can reproduce via rootstock, you’ll need to keep a weather eye to the invaded area, as well as the disposal of any subsequent uprooted plant materials.

When push comes to shove, a number of herbicides have been shown effective at controlling dogfennel while the plants are still under 20 inches tall. Herbicides containing chemicals such as triclopyr, metsulfuron, 2,4-D, atrazine, fluroxypyr and simazine have provided excellent control of dogfennel in a wide range of turfgrasses.

Nochaway Ag Update

When it comes to pasture and hayfield management, weeds are pests year round. With the broad spectrum of weeds here in the Southeast and the climate to sustain them, it is a struggle staying ahead of them. Over the last few years, I have gotten calls in the spring through early summer about controlling weeds in pastures and more often than not, those weeds include dogfennel and thistles. These are two of the most common weed problems for producers in Georgia.

First we will start with the thistle complex as it is often overlooked during the best time for control. Starting in mid-January through mid-March, producers should scout for the presence of thistles in the rosette stage of growth. This is the stage of growth where the plant is low to the ground and grows outward from its taproot as a mass of leaves just above the soil surface. It is easy to drive by a hayfield or pasture and not even suspect the presence of thistles. The thistle complex consists of several different species but they are all treated as one complex.

Timing is the most critical element in the management of several of our weeds and thistle is no exception. When in the rosette stage, chemical control of thistle is much better than if the plants are bolting, or growing taller from the center. Also it is even harder to kill a thistle once it has begun to flower. It benefits the producer to attack thistles during the rosette stage as it is susceptible to a broader range of cost effective herbicides.

Dogfennel is also a weed that has substantial economic importance to area producers. Dogfennel can spread from its root stock causing increasingly larger groups that shade the desired forage and reducing yields. It is particularly troublesome in overgrazed pastures or areas where pH has drifted below desired levels for most grasses. Although dormant during the winter months, growth resumes and seed germinates as early as April and can grow to sizes that shade desirable forages in a few short months.

Although they are easier to scout than thistles, dogfennel requires the same timely approach for adequate control. When less than 20 inches tall, dogfennels are much easier to control and producers have a broader range of herbicides from which to choose. After they exceed 20 inches in height, some of the more cost effective herbicides become less effective and a more costly herbicide may need to be used for adequate control.

For help in developing a management strategy for these and other pests in your pasture or hayfield, contact your local extension agent. Be sure to discuss control options, the timing of herbicide applications, drift concerns, and grazing restrictions. Always refer to the Pest Management Handbook for recommended pesticides.

Controlling Dogfennel In Pastures

We are starting to look at late summer pastures weeds. Yesterday, we looked at dogfennel (Eupatorium capillifolium) and mint in a Bahia pasture that is two years old. Dogfennel is normally considered to be unsightly, but research has shone that yield loss can occur in bahiagrass if dogfennel is not controlled before mid-summer. Cows don’t normally eat dogfennel, but will when forage is low in qyaility. Dogfennel has a toxin which can make cattle dehydrated.

Dogfennel bolting in Bahia pasture

Control

The biggest thing with controlling dogfennel is timing or really height. It can grow from overwintering rosettes. Seeds will also germinate and sprout at 65 degree soil temperature. Though a lot about it’s biology is known, treating based on heigh is more recommended.

Treatment

2,4-D and dicamba do good on dogfennel, but we obviously cannot use from most of April through the fall. In Florida, dogfennel growth will start sooner. For us, germination will occur in late April, after we put out our Weedmaster application. During the summer months, Pasturegard (fluroxypyr + triclopyr) is another option for us. The rate depends on height. When dogfennel is < 36″ tall, use 1 pt / A. When dogfennel are > 36″ tall, use 1.5 pt / A. This rate is effective on large dogfennel, even 5 ft tall.

More of this information can be found at Dogfennel: Biology and Control

Everyone has seen those lacy fern-like spikes with the tiny daisy-like flowers in the summer. This time of year what’s left of the flowers turns white and they can be quite attractive if they are not invading our flowerbeds.

This weed is dog fennel or wild chamomile (Eupatorium capillifolium) and it can have many uses aside from its looks. Many think it adds to a perennial garden. If you’ve ever pulled any, you noticed a strong odor. Some like the smell and others don’t.

Mosquitoes generally don’t like it. Native Americans used this perennial to repel them and some folks still use it today. I haven’t noticed much benefit, but likely additional preparation might be helpful. Juice from the entire plant can be extracted and applied topically to treat bites of reptiles and insects.

Dog fennel can grow six or seven feet tall and can take over an area if not kept clipped. Its leaves are hairless, but stems are quite pubescent.

It grows best on moist fertile soils and invades quickly. This upright aster relative tolerates dry conditions and does well on sandy soils. It also tolerates a wide pH range.

Regular mowing generally keeps dog fennel from becoming a problem in our lawns. It generally self-pollinates, but wind spreads pollen and seeds meaning plants could pop up anywhere. Dog fennel is not difficult to control chemically. Numerous herbicides will kill it.

One reason I chose to write about dog fennel is because there is much confusion surrounding it. Some foragers and herbalists speak in glowing terms. It is also useful for lost hunters to recognize, because the dried down from flowers and foliage makes great tinder. Being able to start a fire could save lost hunters, hikers and fishermen.

Other folks, especially livestock farmers consider this plant poisonous and a nuisance. Toxicity problems are not common since dog fennel has poor palatability. Even deer don’t usually eat it unless there is no other food left.

The major culprit is an alkaloid called pyrrolizidine. As a general rule, alkaloids are bitter-tasting compounds. This one in significant quantities can seriously damage the liver. Leaves also contain low levels of tremitol, which causes dehydration when ingested by cattle.

I do not recommend eating this herb. It is not a substitute for domestic fennel. The two species aren’t even related. Fennel is in the carrot family.

Some use the foliage in small quantities as a spice and many sources list it as edible. Some call it wild chamomile, but I wouldn’t recommend brewing any tea from it if you value your liver. Common names of plants can be dangerous.

I consider dog fennel useful only when used externally. Oils in the foliage can soothe sunburn and other skin irritations. Numerous sources document its insecticide potential. To many it also has aesthetic value.

The green lacy stems are attractive in flower arrangements as filler material. In fall the dried flowers make a nice accent also. Dried stems resemble florist Caspia but don’t last as long before shedding.

Above is a young dog fennel plant in fall. Normally young seedlings like this are more prolific in the spring.

Older plant in the fall having shed most of its white petals and seeds

Another mature dog fennel plant showing a bit more white chaff

Ted Manzer teaches agriculture at Northeastern High School.

Dogfennel (Eupatorium capillifolium): Biology and Control1

B. A. Sellers, Pratap Devkota, and J. A. Ferrell2

Dogfennel (Eupatorium capillifolium) is an aggressive native perennial found throughout much of the Southeast. Dogfennel is particularly troublesome in unimproved or overgrazed pastures where it adds to the decline of forage yield and quality. Although dogfennel is generally considered to be only unsightly, research has shown that significant bahiagrass yield loss will be observed when dogfennel infestations are not removed prior to July 1. Cattle do not normally feed on dogfennel, but they may eat it when more suitable forages are lacking. However, the leaves contain low levels of the toxin tremitol, which causes dehydration when ingested by cattle. Dogfennel is currently the number one most commonly occurring pasture weed in Florida.

Biology

Dogfennel growth frequently occurs from overwintering rosettes, but seeds will also sprout and grow when soil temperatures reach 65°F. The growth will generally consist of a single, non-branching shoot that can exceed 8 feet in height. The leaves are very thin (Figure 1) and emit a strong odor when crushed. Near Gainesville, Florida, the life cycle will resemble the information found in Table 1, and these growth patterns will occur earlier in South Florida.

Figure 1.

Dogfennel (Eupatorium capillifolium) showing finely dissected leaves.

Credit:

Jason Ferrell, UF/IFAS

Table 1.

Life cycle of dogfennel near Gainesville, FL.

Dormancy:

January–March

Bolting:

April–June

Flowering:

September–October

Fruiting:

November

Seed dispersal:

November–December

Seeds are surrounded with hairs (similar to dandelion), allowing effective dispersal by wind. Therefore, bare areas in pastures are ideal environments for windblown seed to become established.

In addition to growth from seed, dogfennel can spread from underground rootstocks. These rootstocks arise from the main taproot and grow laterally in all directions. This process will result in the production of distinct plant colonies in only three years.

Figure 2.

Dogfennel colony resulting from lateral spread from rootstocks.

Credit:

Jason Ferrell, UF/IFAS

Herbicide Timing and Selection

Although we have a fairly thorough understanding of dogfennel biology, there is no specific month when an herbicide application for dogfennel control is recommended. Rather, it is much more important to select an herbicide program based on dogfennel height (Table 2). Smaller plants are much easier to control than larger ones. In fact, dogfennel less than 20 inches in height is readily controlled with 2 qt/A 2,4-D amine or 1.5 qt/A WeedMaster (dicamba + 2,4-D amine, others). Control with these herbicides tends to decline as dogfennel plants grow above 20 inches. However, it is not uncommon to reach levels of 80%–85% control with these herbicides when plants are between 20 and 36 inches tall. Above 36 inches, the level of control is dramatically reduced and a more rigorous herbicide program is recommended.

There are several options for controlling large dogfennel (Table 2). When choosing an herbicide program, we need to consider the weed spectrum within a given pasture as well as the forage grass present. If dogfennel is the primary target weed in the pasture, Pasturegard HL at 1.5 pt/A is an extremely effective option regardless of the plant’s size at the time of application. However, if other weeds such as tropical soda apple are present, we recommend applying GrazonNext HL at 1.5 pt/A in combination with 1) Pasturegard HL at 0.5 pt/A, 2) 2,4-D amine at 3 pt/A, or 3) 2,4-D + dicamba at 2 pt/A. All of these herbicide combinations can be safely applied with minimal injury to forages in Florida. The only exception is that products containing 2,4-D should not be applied to limpograss (Hemarthria) between May 1 and November 1, as severe injury may occur. For more information concerning weed management in limpograss, please refer to the EDIS publication Weed Management in Limpograss (http://edis.ifas.ufl.edu/ag344).

In addition to dogfennel height, there are environmental factors to consider. The driest time of year, especially in South Florida, is April and May when most dogfennel is relatively small. Even though small dogfennel is typically the easiest to control, herbicide effectiveness can be severely impacted by drought conditions as plants tend to “harden-off” to limit water loss. In most cases, as long as the plant is not wilting during the day, the herbicides listed in Table 2 will provide effective control. However, it is important that application rates are not reduced. We have seen 2,4-D amine and 2,4-D amine + dicamba fail to effectively control dogfennel under dry soil conditions on several occasions.

Dogfennel Infestation and Forage Production

There is no doubt that weed infestations have a detrimental impact on bahiagrass production. Until recently, however, the extent of the impact was not known. In an experiment conducted in 2007 and 2008, season-long production of bahiagrass was measured in response to the timing of dogfennel removal at increasing dogfennel densities.

The data indicate that a pasture with > 50% infestation will yield 42%–74% less bahiagrass than a dogfennel-free pasture, if dogfennel removal is performed in May. Waiting until August to remove dogfennel from pastures with > 50% infestation resulted in a more than 75% loss in bahiagrass yield. As such, we recommend that dogfennel be controlled as early as possible if more than half the pasture is infested.

Experimental pastures with < 25% dogfennel cover had relatively consistent bahiagrass yields as the growing season progressed. Even though the bahiagrass yield was lower than the plots without dogfennel, it appears that bahiagrass is somewhat tolerant of light dogfennel infestations. The same does not hold true for higher levels of dogfennel infestations. Bahiagrass yield declined as the growing season progressed in both 50% dogfennel cover plots as well as > 75% dogfennel cover plots.

From this research we concluded that when pastures are infested with < 25% dogfennel cover, herbicide applications may be delayed for almost a whole growing season, especially if dogfennel plants have become so large that more expensive herbicide mixes are needed for optimum control. Conversely, at dogfennel cover > 50%, dogfennel should be controlled as early as possible to prevent substantial yield loss and potential stand reductions.

Dogfennel is an important pest that is more destructive to bahiagrass pastures than may be realized. We believe it is important to focus on this weed and remove it as infestations increase beyond 25% groundcover. Unfortunately, providing a “one size fits all” recommendation for dogfennel control is difficult, if not impossible. Each pasture is going to require some thought with regard to herbicide selection and application timing based on both the environment and dogfennel density. We recommend you review the information in this article, along with the following EDIS articles:

If you need assistance with your particular situation, please contact your local UF/IFAS Extension agent.

Tables

Table 2.

Herbicide options for dogfennel control in pastures. Herbicide costs are estimated and may vary upon the amount purchased; cost of application is not included in the herbicide cost.

Active

ingredients

Trade

names

Rate

Cost/A

2,4-D amine

Many

1.5–2 qt/A

Apply to dogfennel less than 36 inches tall; apply higher rates as dogfennel approaches 36 inches.

2,4-D amine

+ dicamba

WeedMaster,

others

1.5–2 qt/A

Apply to dogfennel less than 36 inches tall; apply higher rates as dogfennel approaches 36 inches in height.

fluroxypyr +

triclopyr

Pasturegard HL

1–1.5 pt/A

$14–21

Apply 1 pt/A when plants are less than 36 inches tall; apply 1.5 pt/A to plants > 36 inches. Applications of 1.5 pt/A are very effective on large dogfennel exceeding 5 ft in height.

aminopyralid + 2,4-D amine

GrazonNext HL

1.5 pt/A

Apply alone to dogfennel less than 30 inches tall when pastures are also infested with tropical soda apple; when plants are > 30 inches tall, tank-mix GrazonNext with 3 pt/A 2,4-D amine, 2 pt/A 2,4-D + dicamba, or 0.5 pt/A Pasturegard HL.

Footnotes

This document is SS-AGR-224, one of a series of the Agronomy Department, UF/IFAS Extension. Original publication date July 2004. Revised May 2013. Reviewed February 2019. Visit the EDIS website at https://edis.ifas.ufl.edu for the currently supported version of this publication.

B. A. Sellers, associate professor, Agronomy Department, UF/IFAS Range Cattle Research and Education Center; Pratap Devkota, associate professor, UF/IFAS West Florida Research and Education Center, Jay, FL; and J. A. Ferrell, associate professor, Agronomy Department; UF/IFAS Extension, Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication do not signify our approval to the exclusion of other products of suitable composition. All chemicals should be used in accordance with directions on the manufacturer’s label.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county’s UF/IFAS Extension office.
U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.

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