I’ve written before about reducing roots when collecting trees. Even though my collecting season is about over, some of you may just be getting started. So this isn’t a bad time at all to review some principles – and surprises.
Before I get into this topic, I do need to stress that the information here is based solely on my own experience with certain species. I collect almost exclusively deciduous trees. Add to that a few broadleaf evergreens such as Chinese privet, Yaupon and today’s subject, Live oak. These species behave similarly to all of the deciduous species I collect, and so what I’m showing you here is applicable. Or put another way, don’t do this with a pine or juniper.
So here’s the Live oak, Quercus virginiana, that I chose for lifting and potting. Not a huge tree, but the trunk is nice and there are some well-placed branches. I whacked off most of the tree – you can see where I made the chop. The bonsai comes from what’s left.
In a few minutes I had the tree out of the ground and had washed off the roots. That’s when I got a not-unexpected shock. Look at how big those roots are! Now, I’ve grown this tree along with a bunch of others from seed collected in 2010. When I went from the growing tub to the ground, I took all of the taproots off. But that didn’t stop the tree from producing very large lateral roots in the process of getting itself established. Contrary to common belief, Live oaks grow quickly when they’re young. This specimen was about eight feet tall before I chopped it back. So the roots you’re looking at are the roots this tree planned to use to grow much bigger much faster.
Can you believe I ended up with this little root? I was a bit surprised myself. But I had to get those whoppers out of there, because the tree wasn’t going to fit into a bonsai pot any time soon if I tried to leave them and gradually work them down. So I bit the bullet.
This brings up a very important point when you’re collecting deciduous trees, namely, don’t leave the roots too long. It isn’t necessary, first of all, and it ends up causing headaches when it’s time to put the tree in a bonsai pot. Ideally, when you collect a tree – or basically a trunk, because it may have zero branches – you should have in mind the finished height of the tree and what size bonsai pot it’ll end up in. If you size your pot correctly, those long roots you leave on because you’re worried about cutting off too much just aren’t going to fit. Take it from me; I’ve learned this lesson the hard way.
Is this tree going to survive the drastic root-pruning I gave it? Obviously, any given tree may not survive collecting, but I think I’ve got a pretty good shot. This tree has enough root tissue, and it’s been reduced enough on both ends, that it will be prompted to regenerate what’s “missing.” In a fashion analogous to rooting a cutting, only more reliable, all trees have a strong “urge” to survive and in order to do so will grow roots and leaves. That’s really the basic principle that allows us to collect trees in the first place.
This Live oak needed one more challenge, so I put it directly into a bonsai pot. I buried the minimal roots pretty deep, to ensure they stay moist.
And finally, after a little wiring and trimming. Assuming it survives, this is going to make a pretty neat broom-form Live oak bonsai. The trunk base is 1″ in diameter, and it’s 16″ to the tip of the apex.
Let me know what you think by leaving a comment below.
I started using the drastic method a few years ago, and I have never regretted it. The process doesn’t yield 100% results, but nothing does. Now that I am repotting my trees from before I started using the drastic method I am really shaking my head about how indecisive I was with the roots. It definitely pays to have that final pot in mind when making those root cuts at collection time. This is invaluable advice that everyone in bonsai desperately needs to know … thanks Zach!
Thank you, Jeremy. As for the live oak, so far so good. When it starts pushing new growth it’ll be out of the woods, and I’ll post an update.
Do you use a rooting powder when you cut the roots back so drastically?
Yes, whenever you cut back a larger root it’s best to dust with rooting powder.
Thanks for the info. I have 5 live oaks of different sizes that I’ve been cutting on for 2 years. Since I’ve done little collecting, your hints are invaluable. The last bougainvillea I collected months ago has too many roots and will have to be seriously cut to ever fit in a bonsai pot. Each side of the 3 trunks are 5 inches around and intertwine. I have a new saw so I’ll give it a try.
Glad I could help, Jane. Bougainvilleas will take drastic root pruning and never skip a beat, as long as you’re in the growing season.
Zach, I’m mortified, yet I can’t look away.
LOL.
This is a very common problem in container grown trees. Following your lead I have committed to biting the bullet up front. In the last two years I have only lost two trees out of quite a few handled this way. Solid advice assuming you don’t have a big investment in the tree at that time. Next best advice is to let Zach take the risk and wait a year.
Thanks for the comment, Doug. Any update on Parsley hawthorn propagation? Mine are coming out now, so I imagine yours ought to be as well.
Working on it. – I’ll know in a few months.
Thanks, Doug.
Nice job on the collecting. Ihave always been intimidated root pruning, i have a very large
Zelkova with one very large root. It is about 50 years old so I want to be very careful with it.
owned it for about 5 years..
I really like the branch wiring can’t wait for future photos.
Thank you, Robert. I understand your reluctance on the old Zelkova. Have you considered layering it?