Home » bplant.org Blog

bplant.org Blog

A Control Section for Invasive Plants

April 15th, 2021 by Alex Zorach

Up until now, our plant articles have been purely descriptive, focusing on ecological aspects like habitat, faunal associations, life cycle, genetic relationships to other plants, and also on identification. However, the ultimate purpose of our site is to preserve, protect, and restore biodiversity through education and information.

Invasive plants represent a major threat to biodiversity because of their potential to disrupt ecosystems, outcompeting native plants and often supporting fewer native insects. But attempts to control invasive plants are often limited by knowledge. Attempts to remove a species without understanding its ecology, at best can waste resources and be ineffective, and at worst can actively damage the environment in multiple ways. But a well-informed effort can often achieve large results with minimal effort.

Japanese honeysuckle (Lonicera japonica) smothering trees in edge habitat. This plant is often hard to completely remove, but minimal effort can reduce its extent and prevent it from going to seed.

To address these concerns, we have added a control section to the articles for plants invasive in North America. We hope this section can help people and organizations use their limited resources effectively, maximizing their benefit and minimizing effort and cost, and of course, avoiding unintentional harm.

How can control attempts fail or backfire

Here are some of the more common ways that invasive plant control can go wrong:
  • Removal of annual or biennial plants after seed has been produced and dispersed. In this case, uprooting, cutting/mowing, or spraying herbicide on plants may have no benefit at all, and in some cases may actively facilitate the spread of the plant's seeds.

  • Lack of follow-up. Most invasive species are resilient and will resprout or re-establish after a control attempt. For example, garlic mustard (Alliaria petiolata) usually requires at least two years of removing all flowering plants in order to see a major reduction of its numbers, and at least 5 years of follow-up to fully remove it from an area, due to its persistence in the seed bank. A one-time effort or even repeated efforts with insufficient follow-up may have little benefit in the long-run.

  • Unintentionally spreading invasive plants. Such spread can occur by transporting seed, stem, or roots to a new location while removing a plant from a site. This problem can occur when removing plants that have already produced seed, and also with removing roots or rhizomes of plants such as Japanese knotweed (Polygonum cuspidatum) or creeping thistle (Cirsium arvense) that are able to reproduce vegetatively through underground rhizomes or root fragments. Non-target invasive plants can also be spread if you remove soil containing seed or roots and move it to a new area.

  • Herbicide use without follow-up to remove resistant plants. Failing to return to identify and remove resistant plants can contribute to the evolution of herbicide resistance. If any resistant plants survive, subsequent attempts to control the plant by the same method will be less successful. Once plants adapt to an herbicide, their resistance can spread to other populations, which is why most plants that are common agricultural weeds have already evolved herbicide resistance.

  • Killing non-target plants. This problem is most common when herbicide is applied to an area where an invasive plant is growing together with native plants, but can occur with other control methods too, such as if uprooting, clipping, or mowing an invasive plant kills or damages native plants growing together with it. In many cases, killing non-target plants can worsen the infestation of an invasive plant by removing native plants that were competing with it.

  • Disturbance allowing the establishment of new invasive plants or re-establishment of the original target plant. This problem frequently occurs with soil disturbance from tilling soil or uprooting plants, it and can also result from the blanket killing of vegetation by herbicide, mowing, or other methods.

  • Control where control is not necessary or beneficial. Just because a particular plant is invasive in North America doesn't mean it makes sense to control it in all cases. Some plants are only invasive in some parts of the country, like how European holly (Ilex aquifolium) is invasive in the Pacific Northwest, but not in the eastern U.S. Other plants, such as white clover (Trifolium repens), are introduced and widespread, but mostly survive in areas around humans and rarely pose a problem to wild ecosystems. Even with plants that are locally invasive, there may be little benefit and/or high costs to controlling it on certain sites, such as on isolated sites with few or no native plants.
Prickly lettuce (Lactuca serriola) is often favored by ill-conceived control attempts of other species. It is resistant to most herbicides, but has high light needs, and thus herbicide application in an area tends to favor its establishment or survival by preferentially killing competing vegetation. This individual is growing in an area between railroad tracks and a parking lot, where herbicide is frequently sprayed. Prickly lettuce is best pulled by hand early in its life-cycle, or cut to the ground right as it begins to bloom.

Our control sections take all of these things into account in recommending which approaches to use in which circumstances, and we explicitly warn the reader about the most common dangers in trying to remove a particular species by a particular method.

Resources are limited and efficiency matters.

Invasive plant control is a difficult and often resource-intensive effort, requiring time and exertion, tools, and other supplies. In most cases it is not realistic to completely remove an invasive species from a location, and even when it is possible to remove some specific species, land managers must often pick and choose their battles, making a complex cost-benefit analysis to decide which species are worth the effort.

Using resources more efficiently means you can successfully carry out more of these battles, making sure your efforts have the maximum effect for protecting and restoring native plant populations.

Timing is critical in invasive plant control. Here a large monoculture of garlic mustard (Alliaria petiolata) has already begun forming seeds. It is easier to control this plant earlier in the season before seeds have formed, as pulled plants can be left in place to die; now extra work must be done to remove the seeds and care must be taken to avoid spreading them to new habitats. Later, once seed is dispersed, it will not be possible to control this generation of plants at all.


By better understanding the life-cycle, growth habit and physical structure of each species, as well as its unique adaptations to its environment and limitations, you can avoid unnecessary work. You can also better choose which plants to tackle along with where and when to do it. We hope our new control section will provide exactly this information.

Take a Peek

Here is a sampling of our published articles on invasive or introduced plants, where we have added a control section:
Expect our resources on invasive plants and control methods to expand over time.

Help us to help others do more with less.

You can help guide our work by contacting us and requesting plants you would like us to prioritize, and by giving us any additional information or control tips.

Also, please consider donating to support our work. This site is currently exclusively donor-funded and as our amount of donations are still minimal, it is essentially a mostly-volunteer effort at this point. You can visit our support FAQ and finances pages if you have more questions.

As we explained above, invasive plant control is costly and often information-limited, so by donating to this project you can help to reduce the total costs of invasive plant control in society, allowing others to more efficiently utilize their existing budgets, while magnifying the positive effect that those efforts have on protecting and restoring biodiversity. At this point even small recurring donations such as $10/month make a big difference, and such a cost is small relative to the amount that many organizations and land owners already spend on invasive plant control.

Progress Bars & State Ecoregion Legends

March 11th, 2021 by Alex Zorach

We are excited to announce some new features: we have added progress bars to several pages, and also added legends and ecoregion lists to state ecoregion pages. We also added a column to tables listing articles, showing which plant and ecoregion articles are complete, on search pages and subregion listings.

At a glance, you can now see which pages are complete before visiting them. These changes will also help us to prioritize our work. These changes show up several places on our site.

Search Pages: Plant Lists

When you use the search bar at the top of our site to search for plants by common or scientific name, the results are displayed in a table, and the listings include a mix of articles in various stages of completion.

There are two new columns in the table. The first has a ✓ mark for articles whose text is complete and published. The final column notes the presence and resolution of the range map, which may be absent, auto-generated as explained in this blog post, or researched to be accurate to a certain level of ecoregions (usually 2 or 3, but we are hoping to get to 4 in time.)

Underneath the results, there is a yellow legend explaining what the symbols mean.
A screenshot of search results for quercus, with progress bars in the results and also in a section at the bottomThis screenshot shows two different types of progress bars on search results: one for the range map for each species, and bars denoting the completion of the set of plant pages returned in the search.

At the end of the page is a Progress section, showing the total progress for the subset of articles returned in the search. A similar section also appears now on pages with lists of subregions, which you can see below.

State Ecoregion Lists and Map Legends

We've had ecoregion maps for all lower 48 US states for over a year, but until this update, there was no list on the page for each state of which regions were found in which state. We recently added these listings along with a map legend.

As with the search page, in the legend we added a column notating which articles are completed, and which still need images. Similarly, there is also a "Progress" section below the legend, both on the pages for each state, and the pages for any ecoregion that has subregions (such as the level 1, 2, and 3 ecoregions.)
Screenshot of new map legend and subregion list above, and progress bar section belowThis screenshot shows the new map legends and subregion list, as well as the progress bar section, in this case for the state of Connecticut.

We hope that these new features will make our site more useful, as well as helping you to track our progress. If you want to help our work progress more quickly, there are also numerous ways to get involved. We are always looking for open-licensed (CC BY or CC BY-SA) images for ecoregions that lack them, as well as for plant pages and ID guides. You can also donate to help fund our work. We also welcome corrections and suggestions on our articles or range maps, including data to help us complete or refine those maps.

If you stay tuned, we have more closely-related features under development too. In the near future we hope to allow you to request completion of specific articles and be notified when they are published. In the meanwhile, take a peek at what we just added! You can start by searching for your favorite plants, or browsing our pages for US states.

Our 2020 Achievements

February 9th, 2021 by Alex Zorach

Like for much of the world, 2020 was a rough year for us, with me falling sick with COVID and becoming a "long-hauler", but in spite of the setbacks and lost work associated with this illness, we still achieved a remarkable amount on bplant.org over the past year.

New Plant & Ecoregion Articles

We now have 59 published plant articles, and 25,142 stub articles. These stubs represent imported data on even more of North America's plants, now covering most native and introduced species as well as many naturally-occurring hybrids. Many these unpublished articles, which are viewable through the site's search function, have substantial amounts of material on them already: 5612 have range maps, 208 have images, and 352 have some text but are not yet complete.

We also made great progress on ecoregions. Moving west and south from the northeast, we have completed all articles on Michigan, Indiana, Kentucky, Tennessee, and South Carolina.

Here is an interactive map of Michigan as a sample:



We also completed much of Illinois, Alabama, and Georgia, and began work on Wisconsin and Mississippi.

Many of these articles, however, still lack photographs. Our blog post about helping us find ecoregion photos explains what we are looking for. If you have or can take or locate any photos that we could use for regions presently lacking photos, please get in touch!

Many More Plant Photos

We added 418 plant photos. Here is a brief gallery highlighting a few of them. Can you identify any of these plants before clicking on the images?


Many of these images were added specifically for use in our plant ID / compraison guides, which leads into our next accomplishment.

More ID / Comparison Guides

We completed and published 23 new plant ID / comparison guides, and began 19 more in-progress. Here are the ones we completed in 2020, as well as 3 more that we began in 2020 and have since completed:
As you can see, we have mostly been focusing on woody plants, but have begun making a few guides about some of the more common herbaceous plants as well.

Interlinking with Databases

One of the most exciting achievements of 2020 was our interlinking of our plant pages with their entries in other plant databases, which you can read about in our previous blog post if you missed it. Since publishing that post, we have added 5 more databases, bringing us to a total of 10, and we have more underway.

You can find our list of such interlinked databases on our websites page, which is updated as we add new ones.

New Homepage

We redesigned our homepage in order to better highlight newly-published and recently-updated plant pages, ecoregion articles, and ID/Comparison guides, as explained in this blog post.

Numerous Small Tweaks

We also made a whole series of small tweaks, some visible and some behind-the-scenes. These improvements include bug fixes, optimizations to make our pages quick to load even when being viewed by many people at once, as well as navigational and user-interface tweaks, and improvements in the pulling of images and descriptions when sharing our pages on social media.
Photo © Leila Dasher, CC BY 4.0, Source.

More Donors & Financial Support

We are also pleased that, in spite of dedicating very little energy to fundraising, we received over four times the amount of donations in 2020 as in 2019. You can find updated information on our Finances page, which is linked to in the footer of our site. Thank you so much to all our early donors!

If you are not already supporting us, please consider donating! You can also find the link in the footer of our site, along with a FAQ that we hope will address any concerns you might have.

We are still a long way from paying a living wage to support my full-time work on this site, which leaves the site's future uncertain. Donating is the most effective way to ensure that bplant.org continues to be developed and maintained, and remains ad-free and freely accessible to all.

What's In Store For The Future?

Besides continuing publishing plant and ecoregion articles, new ID/comparison guides, and interlinking with more databases, we also have some exciting new projects in the works. We are planning on eventually launching user accounts, which will allow users to save or bookmark plants, and also to request the prioritization of incomplete or missing articles. We also are planning the generation of plant lists for a particular ecoregion, which, combined with our ecoregion locator, will allow anyone to type in an address or location, and pin a point on a map, and then access a list of plants native to the region.

There is a lot to look forward to!