I collected this green hawthorn, Crataegus viridis, back in February. Hawthorns are very easy to collect, with about a 90% success rate. As expected, this one exploded with growth in spring. You’ll notice there are two existing branches on this one. I usually remove all of the branching from collected deciduous trees, but this time I decided to leave a couple of the existing older branches as I felt they could add to the character of the tree. Plus they were flexible enough that I could wire them into position.
Here’s the tree after its first wiring. It’s the habit of hawthorns to throw very long shoots with little or no sub-branching in the beginning of their recovery. I wanted to get a head-start on the positioning of these shoots, as I knew they’d harden off during the growing season.
This is the progress of the tree as of today, following removal of all the wire except what’s on the original branches. Isn’t the amount of growth amazing? So the tree is in serious need of a good cutting back, in order to allow for proper development of the structure. As I’ve noted before, the branches of a tree need to taper just as the trunk of the tree tapers. This helps create the illusion of age and maturity. In this particular case, I don’t need massive taper in the branches; rather, I need them to taper gracefully as the trunk does. But I can’t let them continue to grow as they have, or I won’t get the effect I need.
The trimming begins. I’m starting at the bottom of the tree, which is usually how we approach wiring and pruning. It really doesn’t matter where I start, as long as I get everything done right.
Notice how far back this branch is pruned. It’s always worth bearing in mind that the overall profile of the tree needs to be kept close enough in to the trunk to make the tree appear to be a taller, larger, mature tree in nature. The limits of this profile will vary with each tree; some are broader than others, obviously. As you work with more material this will come easier. The main thing is to avoid letting the spread of your tree get out of proportion with the thickness and height of the trunk.
The next few photos are simply a progression of this trimming process. In each case I’m cutting back to the first or second node. In each case the tree will pop a new bud in the leaf axil in two weeks. I’ll wire these new shoots into position, and do no further trimming in 2015.
Here I’ve completed one side of the tree. In the upper part of the tree, I’m faced with stronger shoots. Hawthorns are understory trees, but still exhibit apical dominance. I’ll have to keep this tendency in check as the development continues, and to an extent even after the branch structure is fully developed.
Now I’m working the other side of the tree. Same principles as elsewhere. Keep the upper shoots in check. Cut back hard to produce a graceful tapering in the branches that mirrors the taper of the trunk. Wire the new shoots after they’ve grown out and begun to harden off.
Now I’ve moved to the other side of the tree. Remember when you’re cutting new branches back hard that you must be careful not to damage the leaf axils; if you do, the axillary buds will be damaged and you’re likely to lose the branch. This is because the new branch has only a single layer of growth, and for this reason lacks the ability to produce adventitious buds. The best way to avoid damaging the axillary buds is to leave a short stub past the leaf you’re cutting to. This will dry out but serve to protect the living part of the branch. It can be removed later on.
Here’s another tip when you’re working on newly collected material. Notice I have an extra shoot growing right near the chop on this tree. Rather than remove it, I’m going to let it remain on the tree in order to ensure the health of the chop area. I’ll be performing an angle cut in the chop area next spring, at which time this sacrifice shoot will go away.
Now for the result. Only four shoots didn’t get trimmed: The apex, which needs to thicken further before begin cut back (possibly later this year, but most likely next winter); the two existing branches that I want to retain, but which will be cut back next year as well; and finally, the lowest left branch which needs to continue to thicken before getting its first trim.
This tree is for sale at our Hawthorn Bonsai & Pre-Bonsai page, if you’d like to take its development from here.