Invasive Plants – Page 3

Whether you are tackling a large infestation of the Butterfly Bush, or simply trying to remove a mature specimen from your yard, I will show you exactly how to do it in this guide. I've removed my fair share of large, invasive shrubs over the years and know how to do it so they never return! The Butterfly Bush is an exotic invasive native to China, that has become invasive in various parts of the United States, Canada, Europe, and in Australia and New Zealand[1][2]. Popular in suburban landscaping, it attracts numerous butterflies to it's many flowers and nectar. Should this plant escape (which often happens), it displaces native vegetation and reduces available forage for insects and birds[2][3][4]. A Butterfly Bush that sprouted up along a walking path In order to kill a mature Butterfly Bush, either you must cut down and remove all roots from the ground, then dry the branches and roots before disposal. Or you can apply a herbicide to the plant itself, or cut it down and paint the freshly cut stump with a glyphosate or triclopyr herbicide. For smaller plants, one can just pull & dig out the root. But the strategy you choose for controlling the Butterfly Bush will depend on the level of infestation. So I'm going to break up this article into sections first discussing how it spreads and re-sprouts, and depending on if you are trying to control a vast swath of 'volunteer' plants, a single mature specimen, or just a few seedlings. All of these take different strategies. So, please use the buttons to navigate to different sections depending on the specific information you need. How the Butterfly Bush spreads How to identify the Butterfly Bush Removing mature Butterfly Bush Removing large infestations Removing young plants or seedlings How the Butterfly Bush spreads Self-seeding The Butterfly Bush primarily spreads by self seeding, with the seeds being carried by wind and/or birds. In disturbed areas or barren, recently cleared ground the seed will readily germinate in Spring, and the plant will rapidly grow[2][3]. In areas prone to flooding[5], this is a particular concern as the seed can travel via water (similar to Purple Loosestrife)[4]. Seed head of Butterfly Bush As I document in another article covering the reasons not to plant the butterfly bush, one or the primary reasons this plant can take hold is because it is truly deer resistant. You see, it isn't just Butterfly Bush seeds that will germinate - native plant seeds lying dormant will also grow. But, deer being one of the most common and prolific herbivores will eat native plants but not Butterfly Bush plants, allowing them to grow larger and faster. Thus, they displace native vegetation. Resprouting from buried roots Any root from a Butterfly Bush that is left in the ground, and alive, will resprout new shoots[3]. Effectively creating a new plant. So, unless you are going to dig out the roots, you will need to plan on using herbicides to kill the plant in place, or paint the freshly cut stump. Regrowth from cut stumps Not only will Butterfly Bush spread by seed, but if you simply cut the plant back the stump and do nothing else, new sprouts will emerge from the sprout[3][4]. Additionally, roots can sprout from cut stems, making a new plant[4]. Thus, simply cutting down the plant a single time will not kill it. What this information also means is that you cannot compost freshly cut vegetation, as it may just sprout new roots in your compost pile! Also, don't place them on random piles of trimmings, as again they can make new roots, thus forming a new Butterfly Bush. So, you will need to be prepared to keep cutting new growth week after week until the stored energy in the root system is exhausted, or just employ the cut-stump method. Now, I can tell you from personal experience that you need to paint the stump within a five or 10 minutes of cutting down the bush for the kill to be effective. I've personally done this to dozens and dozens of Bush Honeysuckle shrubs. And in all of that experience, the only ones that would resprout were stumps that I couldn't get to quickly. The bottom line is the sooner you paint the freshly cut stump, the more effective the herbicide will be in killing the root system. RELATED - Find our complete list of invasives, and native alternatives here. Back to top Invasiveness An established Butterfly Bush produce copious amounts of seed. This seed spreads locally as well as via birds to some extent. And while many people will clearly state "it isn't invasive in my yard", I can tell you with first hand knowledge that it will spread to other locations. The picture below is in a semi-wild area about 5 miles from where I live. There is a perfectly healthy and fully established bush shown in the photo (Autumn 2022). Butterfly Bush that has invaded a wild area near where I live. I have had Butterfly Bush plants germinate in my own flower beds even though I've never grown it. Two of my neighbors do have this plant though, and I assume the seed was deposited by a passing bird. In addition to this, this woody shrub grows rapidly and will crowed out native vegetation. Like Forsythia, it can sprout roots from buried stems, which aids in it's expansion. And it has been noted that even if the plant is buried under 18" of sand from a flood, the buried stems will sprout roots and continue the shrubs life[2]. And this will give it an advantage as it will essentially be starting from robust rootstock over any other vegetation. Back to top Identification The overall plant size will typically be 5-15' tall by half as wide. Young first year plants will generally be stingle-stalked and 12" or less. For young plants, rely on leaf identification. Stalk The woody stalk has rough bark when mature that peels. Young growth is green with white hairs. The frequent branching or stalks are usually arching or drooping. Leaves Leaves are oppositely arranged, lanceolate or lanceolate-ovate in shape, up to 10" long by 2" wide with serrated margins. They are medium green in color on top, and light-green to gray underneath with prominent veins. Flower Conical clusters of flowers 3-18" long terminate at the branching. Individual flowers have four-petals and are tubular. In general petals are purple, but pink, white, and yellow varieties exist. Growing conditions Butterfly Bush grows best in full sun and medium-moist soil that drains well. They can tolerate part-sun and are somewhat drought tolerant once established. But will succumb to root rot in constant moist soil or soil that does not drain well. In general though, this plant is invasive for a reason, and overall is quite adaptable in regards to growing conditions that it can tolerate. Back to top Removing a few mature plants If you just have one or several mature plants, you can completely kill them by cutting them down, drying the branches, and digging out the entire root system (See here for detailed guide on removing shrubs). It helps to loosen the soil surrounding the roots using a garden fork or pitchfork, as that will make it easier to dislodge the roots in a single piece. If the plant is in an area that will be regularly mowed, then root removal may not be necessary. And physical removal of an entire Butterfly Bush (including all of the roots) is effective, as long as all roots are removed. If roots are not completely removed, or left in ground, new shoots will regrow. Furthermore, care must be taken to ensure that above ground vegetation is killed or burned, as new growth can occur if disposed of in plastic garbage bags[6], or if left in contact with the ground[2]. Alternatively, you can use poison to aid in the killing and removal of the plant. Spraying the leaves thoroughly with glyphosate or triclopyr is effective at killing mature plants six weeks after application. However, at 10 weeks you should inspect the plant again, and reapply if needed. If you cut down a butterfly bush, make sure you paint the stump with herbicide very soon after cutting it (within 10 minutes) in order to kill the root system. If you do not, then it is likely that the stump and roots will develop new shoots[7]. Removing a large patch of Butterfly Bush Large patches of Butterfly Bush can be effectively controlled spraying of herbicide mixed to the maximum concentration for leaf application, or for cut-stump painting. Of particular effectiveness is Roundup Ultramax or Aquamaster (for infestations near water). If leaves are accurately sprayed within accordance to the directions, you can expect nearly all Butterfly Bush plants to succumb to the herbicide and die within 10 weeks[7]. The USDA conducted research into the effectiveness of four different herbicide mixes. They found two varieties of glyphosate (Roundup Ultramax, and Aquamaster) to be the most effective for spraying on leaves of mature, flowering plants approximately 6' tall (2m), while a mixture of triclopyr (sold as Garlon) to be slightly less effective. Painting Butterfly Bush stumps with herbicide If you are not just interested in removing the Butterlfy Bush (for clearing an area), then you need to apply herbicide to the freshly cut stump in order to kill the root system, lest the roots and trunk resprout new shoots[3][4]. Controlling young plants / seedlings To control smaller and younger plants, a single application of herbicide applied at maximum concentration should suffice if applied during the growing season. Like for larger plants, the USDA research found that Roundup Ultramax (glyphosate), Aquamaster, and Garlon (triclopyr) to all be the most effective herbicides for controlling the Butterfly Bush[7]. Conclusion The Butterfly Bush, despite it's beauty and ability to attract butterflies[8] has caused widespread environmental damage by displacing native plants[2]. Removing it from the landscape is a noble task, as each one left in the wild will sprout many more, compounding the damage. As much as I don't like using herbicides to kill things, I often find myself resorting to them to prevent re-sprouting of the stumps or roots. Or, if the infestation is so great that I personally wouldn't be able to pull them all. And with large shrubs, the root system is quite difficult to control unless you will regularly be mowing it. Learn more about invasive plants here