“Bonsai” response is a term I learned from my mentor Dr. Linda Chalker-Scott. It happens when plants are under stress. In this blog post the stressor is lack of water but it could be something else.
The plant sends out new shoots from the base, trying to bonsai itself in response to the stress. I learned this while going through Dr. Linda Chalker-Scott‘s new Great Courses course “The Science of Gardening“. You can read my blog post review of the course. All I will say here is that it’s highly recommended, if you can get it on sale. The regular price is brutal so forget it, unless you have deep pockets.
As soon as finished the course, I ran into a perfect example from one of my work sites. I normally float around amongst our work crews, helping and training. But, in 2018, we needed someone to take care of a small site so I did it once a week.
In spring we installed new beds on opposite corners. We planted Berberis thunbergii, Sedums, Pennisetums, Carex, Spireas and Japanese willows (Salix integra); and everything got mulched with river rock.
All of the plants developed nicely and the river rock kept weeds in check. But then summer hit and the differences were clearly visible. On the left corner lives a home gardener who waters regularly. On the right corner lives a busy family. Both have garden hoses close by. Let’s talk about the right side.
The tips of the Japanese willow shoots were turning brown so I watered the bed every week. My boss doesn’t normally like to do this but, hey, he wasn’t there and I have research to do for my blog posts.
Then I started noticing new shoots developing lower on the main stem. This was clearly the plant’s bonsai response to water stress. The left bed specimen didn’t do this because the home gardener watered regularly
I didn’t prune off the bonsai shoots until winter 2019. We will see what happens in spring.