Bonsai Tonight

An educational website about bonsai development

Timing for fall pruning

by

Here’s a simple guide for determining when to prune deciduous trees in fall: prune when foliage shows fall color but before the leaves drop.

Porcelain berry

Porcelain berry ready for fall pruning

The timing doesn’t need to be exact, but there are a few things to keep in mind.

If the foliage is still green, the tree has yet to recapture all of the nutrients in the leaves before letting them drop. As a result, pruning early removes more resources than pruning later.

Pruning early can also encourage the tree to produce new growth before winter. This can be very stressful for bonsai as trees typically store enough resources for leafing out in spring, but not enough resources to leaf out in fall and again in spring.

Pruning too late can create similar problems. If all of the leaves have fallen, the tree may be dormant and unable to effectively deal with the wounds created by pruning.

Large wounds require more time to callus over than small wounds. As a result, it’s best to remove large branches in spring instead of fall so the tree can close its wounds as quickly as possible. (If you have to remove a large branch in fall, leave a stub that you can fully reduce in spring.)

Depending on your climate and the species in your garden, the window for fall pruning can be long or it can be brief.

Winters are mild where I live so some trees are growing strong now and will continue to grow through the end of the year.

Chinese quince, for example, can survive very cold winters. Here in the Bay Area, they don’t always lose their leaves in winter. Right now, they are growing vigorously.

Chinese quince

Chinese quince

Quince foliage

New quince foliage in October

Trident maples aren’t as hardy as quince, but they are still growing strong right now.

Trident maple

Young trident maple

Trident maple foliage

Fresh trident maple foliage in October

Often the old leaves yellow and fall away before the newest leaves change color on trident maples, so I expect the lower leaves to fall away long before the newer ones. And if the newer ones still look good in late-November, I’ll remove them to force a brief dormancy.

Another thing to watch out for is that not all trees of the same species go dormant at the same time. Most of my Korean hornbeams, for example, still look healthy, but one has started to fade and is almost ready for pruning.

Korean hornbeam

Korean hornbeam with faded foliage

Young crab apples, on the other hand, are only starting to show fall color and won’t be ready for pruning for several weeks.

Crab apples

Yellow leaves starting to appear on crab apples

I don’t always have time to prune my trees at the optimal time, so I sometimes start fall pruning on the early side. I try to avoid making cuts that will stimulate new growth in the current year, but when I do see new growth, I make note of it as a reminder to prune later the following year.

Have additional tips for fall pruning? Feel free to note them in the comments below.

Subscribe to Bonsai Tonight

New Posts Delivered Every Tuesday and Friday

We won't send you spam. Unsubscribe at any time. Powered by Kit

Reader Interactions

Comments

  1. Hi Jonas,

    When you do your fall pruning, do you defoliate the remaining leaves at the same time or does it not matter since the leaves have essentially lost their function?

    Thanks,
    Lars

    • Hi Lars – yes, I usually defoliate the tree when I do the fall pruning. I’ll occasionally make exceptions – like when the trees are still growing – but my favorite approach is to clean up the trees when I do the pruning.

  2. Jonas,

    Thanks much for the “heads up” on fall pruning. This is so helpful, as are all of your newsletters.

    Gratefully, Richard

  4. This is great information and the photos really help. We’ll be printing this blog off and discussing it at our club meeting tomorrow! (Just like we do with all of your wonderful pine blogs!) Many thanks, Jonas so much well-communicated and clear bonsai information.

  5. A timely piece but perhaps a bit too late for me, Jonas. I trimmed a young kiyohime last week thinking fall had arrived, but we’re hitting 80F days down here in the south bay and the tree has started pushing out a few new leaves. Should I just let them run their course or try to force dormancy early by keeping the tree in a cool dark place?

    • Great question Sean, I’m seeing the same in some of my trees. You can try keeping the tree in the shade until it stops growing and bring it back into the sun in a month or two if it cools down. Depending on what winter does this year, I expect some trees will simply keep growing.