Pruning Victorian box
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.
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.
Thanks for the information. It’s just what I’m looking for, something to keep my Victorian box bushy. Cheers!
Hello,
I was wondering if I could get some advise on my Victorian Box. We have a 40foot Victorian Box in our yard and it looks pretty sad right now. It has very few leaves left with little green and only a few fruits this year. I called an arborist and they told me to remove the whole tree as the species has recently been infected by unknown diseases. Has anyone heard of that???
I would really do what I can to save this tree.
A couple of years ago I noticed several of the Victorian box (Pittosporum undulatum) growing near my property were declining in health. One across the road from my home looked worse and worse. This year it died. Now several of mine are afflicted and I have thick hedges of this plant that have been so wonderful for so many years, so trouble-free, evergreen, easy to grow and reasonably drought-resistant once established in the coastal zone in which I live. This is a real tragedy. Most of my hedges began as volunteers yet ended up as incredibly ornamental parts of my landscape. The wonderful fragrance of the flowers in early spring wafts on the air, particularly in the evening. I will miss that forever once it’s gone. But problems happen. I may replace these hedges with California pepper trees and let them grow like a big thick screen since I have the space. I love California pepper trees and they bring birds.
Sadly, I now realize that it is the glassy-winged sharpshooter (Homalodisca vitripennis) that is attacking Victorian box. This insect is a vector for a bacterial disease Vilella fastidiosa. At first when this insect invaded USA from Mexico it attacked our oleanders. Once beautiful, they are now largely decimated, dead and dying. Grapes also were afflicted, thus harming many vineyards. Now the pest has multiplied to such an extent that it has gone on to other plants. In fact, a wide number of ornamentals and stone fruits are being damaged and even killed by this pest and its attendant bacteria. I understand there are some insecticides that can kill this pest, but as you know I am an organic gardener and do not believe in the use of chemical insecticides. Like drugs, they all have side effects and I firmly believe that cancer in humans is one of them.
My own solution is to find another plant to replace Victorian box. I have already begun thinking and looking around to decide what to use, as mentioned above. In your case I would suggest replacing with a subtropical flowering tree, but first make sure it is not being attacked by the glassy-winged sharpshooter. If I were in your shoes I would consider Cape Chestnut (Calodendrum capense). This is an incredibly beautiful tree once established but make sure the glassy winged sharpshooter is not afflicting it. You might ask the horticulturists at the San Diego Zoo since they have at least one magnificent specimen of this tree. Another possibility is weeping bottle brush (Callistemon viminalis). I am pretty sure that pest won’t like this tree. I know of a big one in La Jolla in a front lawn and have seen many mature ones in Laguna Beach. Victorian box is a bit messy with seed pods and so you have put up with that happily for many years. With these new suggestions, sure you will get some fallen flowers with these trees, but who cares in exchange for the loveliness of the flowers? Also mocking birds love weeping bottle brush. I adore hearing the musical songs of mocking birds and even don’t mind when they sing at night. It puts me to sleep.
I live in Laguna Beach and the Pittosporum Undulatums are being systematically wiped-out. The leaves first turn yellow, then branches go bear, and then tree dies. Usually this is a long process and tree is removed before it is completely dead since becomes so ugly. I have 15 on my property and finally found an arborist that is familiar with problem. Basically, they don’t know what is causing it,other than likely a root disease. UC Riverside and State agriculture Department are looking into it but since it is not a cash crop, not much effort being expended to find cure. I bought a chain saw.
About two years ago I began noticing that Victorian box (Pittosporum undulatum) has been sickening and dying in Del Mar California and other coastal communities in Southern California. My opinion is that it is being struck down by the glassy winged sharp shooter because of the characteristics of what I have been seeing happening to this plant for the last two years. I may be wrong, however, and have no proof of my claim. There may be some other problem. However, I don’t think it’s root rot because my pittosporums are dying in places where they are not being well-watered. In the irrigated portions of my garden—though irrigation is not great and only once a week—they have not yet begun to die. When they do die I will cut them down and plant something else. Thanks so much for writing and sharing your experience.