Plant identification - large lobate leaves and prickles on stem - Ask Extension
While cleaning wild grape and other vines from in and under a large neglected spruce in my yard, I found this growing close to the trunk in deep shade...
Knowledgebase
Plant identification - large lobate leaves and prickles on stem #638242
Asked May 20, 2020, 7:02 AM EDT
While cleaning wild grape and other vines from in and under a large neglected spruce in my yard, I found this growing close to the trunk in deep shade. It stood approximately 2 meters before I cut it. One secondary stem growing from the same base, roughly 1.5 meters. No side branches. Location makes access difficult, so the root is still in the ground. What is it? Is this an invasive I should be doing something (other than cutting it back) about?
Montgomery County Maryland
Expert Response
This appears to be an invasive weed tree named Prickly Castor-Oil Aralia (Kalopanax septemlobus). It has been found in a few counties in MD, including Montgomery: https://www.marylandbiodiversity.com/view/16062.
http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b951
You should be able to control it by physical removal, but if need be because of difficulty working around the spruce, you can paint the cut trunk ends with an herbicide labeled for such use (such as brush killers). As this tree is known to re-sprout from cut-backs, you could opt instead to spray its new foliage with systemic herbicide. If you wish to avoid herbicides, repeated cutting back of all growth will eventually starve-out its root system. Birds purportedly spread its seeds around, so if birds that have found the parent tree as a food source continue to perch in the tree, it's possible more seedlings will appear in the future.
If the area underneath the spruce isn't mulched, or mulch needs renewing, maintaining a good layer should help minimize successful weed seed germination. A layer about 3" deep should suffice for this without harming the spruce or other plantings in the area (keep the mulch off of the trunks and plant bases, however).
Miri
http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b951
You should be able to control it by physical removal, but if need be because of difficulty working around the spruce, you can paint the cut trunk ends with an herbicide labeled for such use (such as brush killers). As this tree is known to re-sprout from cut-backs, you could opt instead to spray its new foliage with systemic herbicide. If you wish to avoid herbicides, repeated cutting back of all growth will eventually starve-out its root system. Birds purportedly spread its seeds around, so if birds that have found the parent tree as a food source continue to perch in the tree, it's possible more seedlings will appear in the future.
If the area underneath the spruce isn't mulched, or mulch needs renewing, maintaining a good layer should help minimize successful weed seed germination. A layer about 3" deep should suffice for this without harming the spruce or other plantings in the area (keep the mulch off of the trunks and plant bases, however).
Miri
