A volunteer asked me this past week how best to deal with or transplant a large shrub which is outgrowing its space. It took me back to a classic interview I did once with world renowned shrub expert, Peter the Shrubber. Here is a little excerpt to answer this stellar question:
Interviewer: Thanks, Peter, for being willing to chat with me in the midst of your busy schedule.
PtS: Absolutely. I always have time for one such as yourself.
Interviewer: Peter, how would you go about dealing with an unruly shrub a home owner is concerned about?
PtS: Well, first I would ask myself how did I get here in the first place. Did I put the wrong plant in the wrong place, too big for the britches so to speak? Did I offer it regular maintenance to control and guide growth or is my shrub dysfunction a function of the lack of care received?
Interviewer: This will not help me in my present circumstance, but is useful for future considerations. So, what would my options be in dealing with my current circumstance?
PtS: Well, it all depends on type of shrub, age of said shrub and growing context. The first thing I might try is pruning. Can I simply cut the plant to the ground or back to next to nothing? Some plants, like lilac, respond well to rejuvenation pruning. This requires identifying the shrub and doing a little research on how it responds to different types of pruning. Spring is the time of year for such an action.
Interviewer: What happens if that is not an option for whatever reason? What else can I do?
PtS: Right, so another option to consider is just wholesale removal and composting, unless the shrub harbors a particular compost threatening disease or something. My third option might be to transplant the shrub to another place in my landscape, and this is where it gets a little trickier.
Interviewer: How is that?
PtS: There are a few tips to increase your likelihood of transplant success. It is a common misconception you only transplant in the spring and fall. You can transplant a shrub any time of the year the ground is not frozen, if you are willing to live with the risks and take the necessary steps to reduce those risks.
Interviewer: Why do they usually recommend spring or fall then?
PtS: That is the time when the best environmental and biological factors align. The first thing I do when I am going to transplant an oversized shrub is to give it a light hair cut if necessary. This allows for two things. One, I get easier access to the shrub, and two, it reduces potential water loss through the leaves. If I take too much, I am also removing the energy stored in the shrub’s stems needed to grow new roots and shoots. Next, I use either a broad fork or spading fork, rather than a shovel, to begin exhuming the plant.
Interviewer: Oh really, what is that?
PtS: My little theory: I keep more of the root system, especially the smaller roots, intact using a fork than cutting with a shovel. I might eventually need a shovel to sever some larger roots or during the final removal, but initially I start loosening the soil around the plant, working in a circle way out at the drip line. The drip line is where the front edge of root growth is happening and where the roots have the least hold. As I loosen, I go closer and closer to the stem and center, working deeper and under. Very often, by the time I get close to the center I am able to get right under the plant and pop it out.
Interviewer: What about those larger roots?
PtS: If I rock the plant, I can see by the way the soil moves where the plant is still attached. If I cannot work it loose with the fork, bring in the shovel. I find using a fork to work a shrub loose has offered me greater success, because how much of the root system I keep intact.
Interviewer: Well, thanks Peter, for your time.
PtS: Absolutely, always happy to help my fellow Shrubbers!
I hope you found Peter the Shrubber’s advice helpful. I know I did. Phew, just thinking about it leaves me bushed.
Josh Steffen, Horticulture and Facilities Manager (and Monty Python enthusiast)