Knowledgebase
2 yr old bare oak trees #944333
Asked September 05, 2026, 3:07 PM EDT
Hennepin County Minnesota
Expert Response
This video illustrates the principles:
https://youtube.com/shorts/qZmiYjUh1Zs?si=YryoN0ZsV1TwC5Wv
Based upon what we can see the the photos, this is how to apply the principles:
The oak in image 0432 is well on its way and needs no pruning at this time.
The tree in 0433 has codominant stems. One stem should be removed.
The stem on the left is straighter and thicker than the one on the right. Remove the one on the right.
The remaining stem is also codominant. Remove both stems angling to the left from the main stem.
What's left (the main stem) may seem like a remnant, but it's best suited to grow into a well-formed tree in the long run.
Bullet galls are present on the oak in image 0432. The following video and publications explain the life history of the wasp that causes the galls (probably Disholcaspis quercusmamma) and smaller parasitic wasps that prey on the gall makers.
https://webdoc.agsci.colostate.edu/bspm/arthropodsofcolorado/Rough-bulletgall-wasp.pdf
https://www.extension.iastate.edu/newsrel/2004/may04/may0414.html
https://youtu.be/39Fdxx_J3K8?si=Jz28osJJZMlOjXs8
Based upon the information in the video and publications, if you wish to remove the galls, now is the time to do it.
Also, keep the area around the saplings grass free and covered with two to three inches of mulch. Be sure the mulch stays three inches away from the miniature trunks.
You may want to erect a barrier (fence?) to protect the saplings from animals and other winter hazards.
Given current drought conditions in the Twin Cities area, water well until the ground freezes.