I have been at war with an our-of-control ground cover called Yellow Archangel. It has crowded out areas of Vinca and Japanese Pachysandra. I’ve been clearing the YA little by little, digging up roots and sifting the soil. Do you have any advice as to how I can encourage the Pachysandra to spread and grow to fill the location where it once thrived? ie should I propagate more of it or just transplant, etc.?
Thanks so much,
Thanks for contacting the Toronto Master Gardeners.
Each of these non-native groundcovers can be quite aggressive–it is interesting that they are actually in competition with one another and that the yellow archangel (Lamiastrum galeobdolon) seems to be winning the battle. Removing the Lamiastrum is labour-intensive; unlike the Pachysandra, it tends to ‘jump around’ to wherever there is bare soil. Digging up the roots as you have been and following the long runner to the next set of roots, making sure as you have that bits of root do not remain in the soil. Obviously, this is a time-consuming process.
You ask how you can encourage the Pachysandra to spread. Once you have cleared an area of Lamiastrum, add some compost/soil to the area and transplant rooted pieces of Pachysandra into it and keep it moist. [You probably are aware that the easiest way to propagate it is to simply cut off some and put cuttings into a container of water until roots form]. Once they take hold in the soil, the Pachysandra should be able to spread. But you will have to monitor the area to make sure the Lamiastrum does not reappear.
Unfortunately, there is no quick way to deal with this problem. Just continue what you have been doing.
Good luck in managing these somewhat invasive groundcovers.