Question from Ruth:
I have a garden question. Father Clark, who is a dear friend of mine, has very old–maybe 20-year-old pittosporum. It hasn’t been pruned much. When would be a good time to cut it back hard. He has green growth on top of a lot of old wood. Thanks so much. It is going to look pretty bad for a bit until re-growth starts.
Answer from Pat:
Cutting a Victorian box tree or shrub (Pittosporum undulatum) back hard can be done at various times of year with various results. If you cut an old pittosporum back in mid summer, regrowth will be very slow. If you cut it back in fall or spring, regrowth will be more rapid and successful. Pittosporum grows a little differently from many other shrubs since each joint or node will put out numerous shoots, often as many as four or five. If you cut off the top growth down to the next joint the entire thing (with leaves removed) looks like the ribs of an umbrella that has been turned inside out by a strong wind. Between the nodes where these radiating branches occur will be a long straight branch in the middle that leads to another node and so forth. So the query is where to cut it? If you cut the central branch back to the lower node the surrounding branches will take off and grow longer, creating a shrubbier tree. Unlike most trees buds exist under the bark all up and down the tree, so even if you cut in the middle of a branch, it will sprout and produce new growth. This means theoretically that you can cut back an old pittosporum pretty hard and it will bounce back and become a shrub again. Or you can prune it more selectively and maintain it as an elegant spreading tree.
No related articles.
Thanks for the information. It’s just what I’m looking for, something to keep my Victorian box bushy. Cheers!
Hi Pat, Thank you! His is the shrub. So, I guess wait ’till spring??
Yes, wait until after Feb. 15 then it’s fine. There are several different pittosporums. If a shrub maybe you are perhaps talking about Pittosporum tobira. If so, these can be pruned into a pagoda shape in age. I have known some to grow as tall as small trees and once grown to this height, they are noble plants. I have never cut back a P. tobira hard. I think it would be better to reduce its size slowly over a number of months, so it will continually branch down further in the plant. But the rule about summer pruning remains. Cutting back hard in summer has a dwarfing effect.
Hi Pat, thank you!!! You are a wizard!!!
I am not a wizard, but I remember a lot of facts about plants and gardening.
Knowledge of that dwarfing effect came from an article on pruning that I read many years ago, in the late 1970′s
I think. I didn’t make it up, but I tested it on my own shrubberies I have found it so very true. A few years later, during the 1980′s
Chuck Kline of Sea World suggested that I cut the ten-foot-tall shrubbery of Pittosporum undulatum in my patio way down to the ground and let them re-grow. The man who
at that time owned the house across the street from me had cut down his trees so we had an ocean view that we had not had for years. Chuck pointed out that I should take advantage
of it. I wanted the pittosporums to stay shorter forever so we have cut them back close to the ground in hot weather in mid summer, and they never grew taller than three feet again.
Since that time we have repeatedly sheared them in summer and it’s been easier to keep them short that way. When we cut in spring or fall they bounce back quicker with longer sprouts. The hotter it is the less rapidly they grow back and with shorter twiggy growth.