Alien Alert

Garlic Mustard

We’ve had an insurgence of alien plants invade our creek side this spring. I have to attribute this new uprising of Garlic Mustard, Alliaria petiolata, to the unseasonably warm winter we’ve had here in Illinois. I imagine, that given that Garlic mustard appears on the noxious weed list for thirty-seven of the fifty states, I am not alone in my mission contain the beast.

It is important for one to know your enemy. Alien identification is critical to eradication!  Gardeners often confuse first year Garlic mustard plants with Wood Violets and the noxious weed, Creeping Charlie.

Wood Violet by Kylee Baumle

Mature garlic mustard surrounded by Creeping Charlie

Creeping Charlie

A description of the adult and yearling plant follows:





  • the adult, flowering plant has alternate, heart or triangular shaped, 1 to 3 inch wide, coarsely toothed leaves, and ranges in height from 12 to 48 inches;
  • it produces one or two stems with numerous white flowers that consist of four separate petals;
  • the petioles are longer on the leaves towards the base;
  • a distinctive onion or garlic odor is emitted from the plant when crushed. The olfactory characteristic of this plant helps to distinguish Garlic mustard from all other woodland mustard plants;
  • its taproot is white, slender and often bent in an S-shape near the top;
  • soon after flowering, 1 to 2.5 inches long seed capsules form, quickly lengthening and maturing to produce more than 100 black seeds per plant; and
  • first year plants have wrinkled kidney shaped, scalloped-edged leaves arranged in a cluster of 3 or 4 round, that form a rosette.

Triangular leaf and white flower


A complete plant profile is available on United States Department of Agriculture: Natural Resources Conservation Service  web page.

Garlic mustard has been found throughout the northeastern and Midwestern U.S. from Canada to South Carolina and west to Kansas, North Dakota, and as far as Colorado and Utah. Early settlers introduced the plant from Europe onto a new continent, North America, and specifically, the United States. Garlic mustard was brought to the New World because people believed it had medicinal properties. Some settlers even cooked with this cool-season, biennial herb.

Clearly, this alien has occupied our soils for a long time, giving rise to a particular stronghold in the shade of upland and floodplain forests, savannas, yards, and roadsides. Invasion has usually begun along the forest’s edge, with the troops progressing along streams and trails. Light, moisture, nutrients, soil, and space are monopolized by the aggressive Garlic mustard once it has taken hold in an area. Once established, Garlic mustard, a fierce competitor, releases its secret chemical weapon, glucosinolates, into the soil, preventing other, desirable, native woodland wildflowers and trees from flourishing. Aggressive spread of the plant has lead to domination of the forest floor and native herbaceous species displacement within ten years.

Native woodland flora’s survival and the wildlife that depend on them are threatened by garlic mustard invasion. Garlic mustard is spread in two ways: an advancing plant front and population expansion facilitated by animal, flowing water or inadvertent human seed  dispersion. Once dispersed, seeds remain viable for five years. In the Midwest, garlic mustard seeds germinate in early April. Vegetative plant growth begins early in the spring, and flowering from May through early June. Viable seeds are produced within days of initial flowering. Seeds begin to ripen in mid-July, and are disseminated throughout the month of August.

Description: Garlic Mustard (Alliaria petiolat...

Description: Garlic Mustard (Alliaria petiolata), seeds. The numbers on the scale are centimeters. Date: 2005-08-19 (ISO 8601) Author: Björn Appel, Username Warden Licence: GFDL, CC-BY-SA-2.5 or CC-BY-SA-2.0-DE (at your option) Related: Comment: (Photo credit: Wikipedia)

Understanding of the Garlic mustard’s life cycle is key to effective control strategies. Over time, warfare tactics may vary depending on the extent of the invasion. However, after the initial counter insurgence, eradication procedures must be applied for eight or more years to insure that garlic mustard seed bank has been depleted. Each spring, vulnerable areas such as woodlands should be monitored to ensure prompt detection of new invasions and help to prevent re-occurrence. A gardener’s arsenal against Garlic mustard includes:

  • hand pulling followed by bagging and burning or deep burial of the enemy;
  •  decapitation at a height of two to three inches above the soil’s surface before flowering. Follow-up monitoring is required to insure complete enemy elimination;
  • chemical warfare may be needed for instances of extensive infestation. Land-locked, enemy eradication can be accomplished with spring or fall application of a 1% or 2% glyphosate solution. Killzall (TM) and Aqua Master (TM) are safer chemical weapons for use near water; and
  • finally, controlled burns, may be used in the spring to kill the newly germinated seedlings. Permits and certification are usually required to conduct a burn. Contact your local fire control agency for permitting requirements prior to using this method.

Prairie restoration requires gardener’s to engage in warfare against invasive aliens such as Garlic mustard. The battle can be long and intensive, but territory reclamation is vital to the growth of the forest communities’ native plants and animals. Ethically speaking, this is a just war!

Related articles


Eberhardt, Laurie and Finger, Jonathan. “Mapping and Testing a Possible Control Method for Garlic Mustard (Alliaria petiolata).” Pierce Cedar Creek Institute,   Ecological Society of America presentation, Aug. 2007.

“Garlic Mustard (Alliaria petiolata).” Invasive Species, Wisconsin Department of Natural Resources, 3 Sept. 2004. Web. 26 Apr. 2012.

Pyle, Charlotte. “Alliaria petiolata (M. Bieb.) Cavara & Grande garlic mustard.” Plants Profile, United States Department of Agriculture: Natural Resource Conservation Services, USDA, Oct. 2002. Web. 26 Apr. 2012.

Wikipedia contributors. “Glucosinolate.” Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, 28 Mar. 2012. Web. 30 Apr. 2012.

Restoration in Progress

Prairie Smoke

Prairie Smoke (Photo credit: pchgorman)

During the past three decades, public interest in prairie restoration has grown significantly. The motivations to participate in ecological restorations vary; for me, working to restore a piece of the prairie, both as a volunteer steward and as an individual, provides a source of spiritual renewal. Not only am I spiritually, but also physically renewed in the process of reclaiming the land and building a piece of the prairie. Sweat equity is a rejuvenating tonic!

An ecologically sound and thriving prairie landscape is built using a complex and diverse plant community comprised of many different species of grasses and forbs. In fact, restoration ecologist, Roger C. Anderson has identified the four components required to recreate an ecologically sound prairie.

Four ingredients necessary for ecological restoration
to be successful include: (1) a vision of what the ecosystem
being restored should be like when the restoration is finished,
(2) an understanding of the ecological processes needed to
restore and maintain the ecosystem, (3) knowledge of the
specific restoration skills and management practices that
are needed, and (4) public support for goals of ecological
restoration and confidence in the principles that form the
scientific basis for restoration. Research can contribute to all
of these components (Roger C. Anderson).

With these four elements in mind, one must also consider that “…each restoration site is unique in terms of its original ecological attributes, kinds, extent, duration and  intensity of human disturbance, and management activities, each restoration solution must be unique” ( Stephen Glass). After thorough ecological assessment of the site, the first physical restoration step requires the removal of invasive plant species from the site. Stephen B. Glass, a restoration ecologist, believes a restoration plan that “…ignores the fundamental causes of the pest species invasion and just treats the symptoms,” will result in a continually frustrating battle between the restorer and the invasive species. He suggests that when one tackles the underlying cause for the invasive species prevalence in a habitat by treating it like a “repair job.” Look at “…what you know, what you don’t know, and what you will need to learn to solve the [restoration] problem” (Glass). Specifically, look for an “… altered hydrology, or soil disturbance, or increased soil fertility. If the underlying cause is not dealt with, then continued frustration and [re-occurrence of invasive species] will be likely” (Glass).

In a previous post, Invasives Begone, I outlined the steps for land preparation in the restoration process. Therefore, once the invasive plants have been dealt with, the seedbed prepared, the next step is to reconstruct the plant community. Native plants are given the greatest opportunity to thrive if local ecotype seeds or plugs are used to reestablish the health and biodiversity of an ecosystem. After the seeds or plugs have been planted, the rest of the first growing season is spent watering and weeding the seedbeds. The second season requires spring removal of dead plant material and weeding. The first blooms are likely to appear during growing season two or three.

Below, I have linked two videos that exemplify a restoration in progress. The prairie restoration demonstration video produced during the 2010 Chicago Lawn and Garden show does a great job of illustrating the steps of the restoration process.

How to Restore a Prairie

The second video also does a nice job of showing the annual progression of a Minnesota prairie restoration garden.

My North American Tallgrass Prairie Restoration/garden

Related articles


Anderson, Roger C. History and Progress of Ecological Restoration in Tallgrass Prairie. Pp. 217-228. Chapter 13, INHS Special Publication 30: Canaries in the Catbird Seat, Univ. of Illinois, Champaign-Urbana 2009. Print.

Glass, Stephen B. “Thoughts on Restoration Management.” WingraSprings, N. P. Web. 6 Mar. 2012.

Uncovering the Stranglehold in Winter

Oriental Bittersweet Vine

Winter’s grey reveals many of nature’s hidden invaders not easily seen during the heightened lush of spring and summer. While quite amazing in appearance, this twisted, woody structure is an invasive, deciduous vine called Oriental bittersweet, Celastrus orbiculatus.

The Oriental bittersweet vine can grow to diameter of 6 inches and 66 feet in length. The alternate leaves are round to oval in shape with margins that possess rounded teeth. In the spring, flowers consist of five sepals and petals that are arranged in clusters of 2-7 at the leaf axils. The flowers give rise to fruit which changes from green to red orange with a yellow capsule upon maturity.

Asian bittersweet (Celastrus orbiculatus) fruit

Image by AussieBotanist via Flickr

Oriental bittersweet or Asian bittersweet is found in forested areas, field and forest margins, meadows, riparian areas and in residential landscapes throughout the temperate eastern US and Canada. More exact statewide and county specific Oriental bittersweet distribution can be found on the United States Department of Agriculture: Natural Resources Conservation Service Page. In addition to its geographic distribution, the vine thrives in full sun to shade and in a wide range of soil types making it a particularly hardy invasive plant.

These vigorously growing vines climb trees, shrubs, or other support structures by winding around them, and in the process, girdle and smother them. Oriental Bittersweet produces dense shade that has a tendency to overwhelm and displace other native plant communities in an ecosystem. In the winter, another negative impact of this extremely invasive plant occurs when the added weight of the snow and ice covered vines breaks and damages trees as well as shrubs.

To eliminate infestations, prolific reproduction via seed and rhizome production must be stopped. Birds and mammals consume the fruits. These ingested seeds germinate at a higher rate than seeds that fall directly on the ground. One way to circumvent the Oriental bittersweet’s reproductive cycle is to prevent seed formation. Infestation of the Oriental bittersweet may be controlled by

  • hand pulling seedlings;
  • cut foliar or stump herbicide applications using Round Up or
  • weekly mowing.

Whatever method one chooses to manage this ecological threat, it is clear that this sinister invasive must be stopped before it crushes the life out the flora around it! So take the time to stroll through your garden this winter to see what invasives the shades of grey reveal.

Go Wild: Suburban Garden Restoration

Why not just let nature do its thing? Over time agriculture, urbanization, as well as the introduction of exotic and invasive species have impacted the land. Quite frankly, we  have man-handled mother Earth and the environment is no longer in its “natural” state, “letting it be” is not an option. The non-native plants we’ve introduced into our gardens compete with the natives depriving them of space and nutrients. These alien species have altered ecosystem in such an invasive manner that their hostile takeover has given rise to temporary or permanent changes to the biological environment.

Change is difficult for all living things. Change requires adaptation to a new way of living. When lives are interconnected to one another, change can be difficult or even impossible. All living things are connected in the food web of life. Entomologists and wildlife ecologists suggest that a change in the available food sources within an ecosystem cascades down the food chain creating an environment that no longer supports some native species. Without a healthy, diverse, native species, loss and resource endangerment will continue.

photo by Paul Geiselhart

Native Sustenance photo by Paul Geiselhart

At the hub of the food web are plants. They are vital to the continued existence of most other creatures on Earth. Plants provide most of the oxygen living things breathe as well as the food they eat. Plants transform the sun’s energy, through the process of photosynthesis, into food for the plant’s consumers. Some consumers, especially native insects, have not evolved to eat, pollinate, or reproduce using the alien plants of their altered habitat.

Birds and many other native creatures rely, indirectly or directly, on native plant species for food and shelter. The fate of the higher level wildlife in the habitat’s food web is dependent on the native insect population. Habitat destruction and species loss have a direct and undeniable correlation. As landowners and gardeners, we can make a substantial contribution toward restoring ecological balance if we design our landscapes to accommodate native plants and animals.

Heron's Catch photo by Jim Schuler

Restoring balance to the habitat requires that  we remove the invasive plant species from our site, so that as we reconstruct the plant community the native plants are afforded the greatest opportunity to thrive. Eradication of invasives can be accomplished by mowing, smothering, tilling, burning, or herbicide application. Unencumbered germination and seedling development of local ecotype seeds is required to reestablish the health and biodiversity of an ecosystem.

Local ecotype native plants not only provide a food source for animals they also use their extensive root system as a natural filter to purify one of Earth’s vanishing resources, water. Whether from a creek, rain runoff, or groundwater, water needs to be conserved and protected. Restoration efforts made by residents, businesses, and the public sector to prevent sediment and rain runoff has been shown to reduce area erosion, flooding, and improves water quality. Reduction of impervious surfaces and lawn size are two ways to minimize flooding and its negative impact on the riparian community.

Native plants restore balance to the ecosystem and add beauty to the land. Native host plants also improve the food and habitat resource base needed support native wildlife. Gardens composed of natives plants conserve water and protect the soil from erosion as well as exposure to herbicides and fertilizers. The benefits of landscaping with native plants or naturescaping are many and the disadvantages few. Most importantly, naturescaping gives suburban gardeners the opportunity to “go wild” in their effort to sustain the local ecosystems.

Recommended reading:

Tallamy, Douglas A. Bringing Nature Home: how native plants sustain wildlife in our gardens. Oregon: Timber Press, Inc. 2007, Print.

Wasowski, Sally. Gardening with Prairie Plants: how to create beautiful native landscapes. Minnesota: University of Minnesota Press. 2002, Print.

Invasives Begone

Garlic Mustard, Canary Reed Grass, and Buckthorn oh my! Reclamation of our property’s Bull Creek shoreline required a lot of DIY sweat. For the past several years, Steve and I have worked diligently to conquer these non-native dragons. With the help of weaponry such as a lawn mower, spade, saw, pruners, loppers, and RoundUp (glyphosate) we have successfully cleared and prepared small sections of our property’s 100ft. shoreline soil for land restoration.

Seedbed preparation is the most important steps in re-creating a prairie. Proper soil preparation provides a hospitable seedbed, aids planting, and reduces competitive weed growth. In our yard, the major invasive species were Garlic Mustard, Buckthorn, Amur Honeysuckle, Canary Reed Grass, Multiflora Rose, Canadian Thistle, Purple Loosestrife, Bishop’s Weed, and Ground Ivy. Several options for soil preparation exist; the route we took is as follows:

  1. Removal of the large Buckthorn shrubs occurred via the use of a mighty saw or loppers followed by painting the remaining stump with concentrated RoundUp. Disposal of the Buckthorn’s woody debris requires that the branches be dried and subsequently burned or removed via one’s yard waste hauler to prevent maleficent re-growth.
  2. Beheading the Garlic Mustard with our lawn mower repeatedly during its growing season for two to three consecutive years put an end to the beast. Mowing to ground level kills a high percentage of garlic mustard plants. The lower the mower blade cuts on the plant, the greater the plant destruction. Repeated cutting insures the prevention of secondary seed formation from the remaining root crown.
  3. Canary Reed GrassMultiflora RosePurple Loosestrife, and Ground Ivy (Creeping Charlie) were removed using a spade.
  4. Depending on the size of the Amur Honeysuckle shrub, a spade or loppers plus RoundUp were used to eradicate the invasive species. Small honeysuckles were removed using a spade; completely digging up the shrubs root ball thereby effectively killing the shrub. Large shrubs were lopped to the ground and the stumps were dabbed with RoundUp to prevent re-growth.
  5. Canadian Thistle was eradicated using RoundUp. The plant is unaffected by removal via digging or pulling given that its root system extends into the soil to a depth of three ft. and therefore can never be fully eliminated.
  6. Bishop’s Weed (Goutweed or Snow on the Mountain), a particularly aggressive beast, which propagates via seeds and spreading rhizomes was removed using RoundUp. Herbicide application was the eradication method of choice for our site given that the previous property owners had planted large patches of the plant along the upper shoreline zone to stabilize the slope. We found the most effective eradication of the plant occurred when we applied the herbicide three to four times annually.

With the invasive species gone and our kingdom reclaimed, prairie restoration could begin. The subjects of this reclaimed land would be plant species native to our northeastern Illinois area. Reintroduction of indigenous forbs, sedges, grasses, and trees begins step 2 in the prairie restoration process.

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