Q: Do you have recommendation for removing non-native ground covers like Ivy (Hedera helix), Bishops Weed (Aegopodium podagraria) , Periwinkle (Vinca) and Lily of the Valley without using herbicide? are these groundcover considered invasive? I know these groundcovers can spread into nearby natural areas and can be aggressive in the garden, but they're in so many gardens / nurseries. Do you recommend removal vs control in some areas?
A: Hey Denise,
Excellent question, but very tough to deal with, which is likely why you are asking.
I would consider Bishops Weed and Lily of the Valley truly invasive within oak woodlands where they negatively impact the ecology. I believe those need to be removed in the long haul over the course of true ecological restoration as they slowly will consume the native woodland floor. I think in home landscapes they likely should be controlled as well as non-natives typically have a propensity to escape and cause havoc with the local ecology, it just may take hundreds of years for them to become problematic.
The good things is that they both (really all these in question) tend to grow in tight groupings. This makes them a good case for long term solarization. But it comes with some downsides, namely selectivity also possibly some insect and soil mycorrhizal impacts. In remnant woodland this can Cause possibly more issues depending the on the scale of the infestations plus the plastic and pollution has its impacts as well if not collected in time and it shreds into tiny pieces.
The application of various tools need to be balanced with benefits and drawbacks in every ecological restoration. These consideration need to be thought of up front and addressed with great care, especially considering the issues we are facing at the moment and headwinds in the future. We can not provide perfect answers for your particual property, only some consideratiosn you need to answer yourself.
Herbicides honestly can have some benefits besides the obvious massive downsides. If you're working in say a remnant woodland where you need to preserve high quality ground flora you could selectively apply herbicides, leaving the good native plants in place. The native plants can rebound providing integrated pest management improvements and reduced herbicide applications in the future. You also would likely not as heavily impact insect and soli mycorrhizal acutely, but obviously there are no direct studies I am aware of relating to control of these particular species under the aforementioned circumstances. Herbicides have their obvious down sides as well and every situation needs to be evaluated and aligned with the customer and environment in mind.
For the ivy’s, solarization, flaming, controlled burning, all in combination with hand pulling and native plant augmentation can be effective if performed in concert with each other.
Also replace these species with native plants to aid in future battles as it will take several years with any of the above-mentioned approaches.
Chief Ecological Officer