Posts tagged “Ginkgo biloba

Do Ginkgo Wounds Heal?

I’ve heard and read several times that “Ginkgo scars never heal”. I’ve also heard and read “Ginkgo scars heal, but extremely slowly”. My experience with my one Ginkgo leads me to believe that the latter is true. Or wait. Maybe both are true?

My little Ginkgo has lots of old dime-sized wounds that were never really cleaned up. Last July I ground two down with a dremel, exposed the cambium, and packed them with the clay-type wound sealant.

July 2012. Terrible picture, but hopefully you can see the cleaned up wounds. Before, they looked like the other old wounds that are all over the trunk.

July 2012. Terrible picture, but hopefully you can see the cleaned up wounds. Before, they looked like the other old wounds that are all over the trunk.

The other day I removed the cut paste to have a look. One of them (smaller one on the top) has definitely produced a significant callus. For such a small wound, the callus is moving very slowly. A maple probably would have easily healed over this wound by now. The other larger one at the bottom doesn’t seem to have done much at all. I can’t really explain what the difference is. Maybe something to do with localized sap flow.

Smaller one beginning to callus over. Tweezers for scale.

Smaller one beginning to callus over. Tweezers for scale.

This is the larger one. A tiny callus appears to have formed around the edges, but it hasn't really moved at all.

This is the larger one. A tiny callus appears to have formed around the edges, but it hasn’t really moved at all.

I will continue to re-wound these calluses to keep it moving, and will clean up the rest of the wounds on the tree bit by bit, hoping that they respond well. Either way, the end result will look better than it does now.


Another Season Done

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Pruning Ginkgo to Develop Ramification

Ginkgo have a bad reputation for developing ramification, but that doesn’t mean they don’t ramify at all – they just need some encouragement! Unlike other deciduous species like Maple or Elm that will develop some ramification even with improper cutting techniques, Ginkgo will barely ramify at if they are not cut properly. Still, even in the best of cases, Ginkgo ramification cannot hold a candle to that of maples… but that is just the character of the tree. They are still a great species to work on.

This post outlines the pruning techniques I use on my Ginkgo in USDA zone 6.

The first step is making sure the tree is growing strong. This tree was repotted in March but has grown better than expected.

I don’t cut my ginkgo until it is showing very strong shoots like this (about five pairs of leaves). This gives the tree some time to build up strength. I find that if I cut it too early, the tree doesn’t respond well.

Here is a typical gingko branch. The buds circled in red are backbuds. Ginkgo backbuds very well, and most buds open up in the spring. However, the problem with Ginkgo is that it is hard to get these backbuds to extend into twigs. Usually only the end of the branch (circled in blue) will extend during the growing season and the backbuds will just form winter buds. Therefore, you need to cut back the tip of the branch to one pair of leaves to redirect some strength to the backbuds. This is a rather weak branch, so the side buds may not even start to extend until the process is repeated next year. Again, I find that if the tree is allowed to gain some strength in the spring, you will have much better luck getting the backbuds to extend.

Here is a stronger branch after cutting the tips back. This branch is strong enough that I would expect some of the back buds to extend.

Strong apical nodes that have not yet extended may have 3-5 leaves instead of the usual 2. Cut off some leaves to leave just a pair. This weakens the outside of the tree and allows more light into the inside. This is especially important for the top of the tree since Ginkgo are very apically dominant.

After cutting. I will continue to fertilize the tree heavily and the process may be repeated again in the summer. Further leaf-thinning may occur throughout the season.

Really, the pruning techniques for Ginkgo are very similar for most deciduous trees. The development is just much slower and the end result less ramified. However, I’ve found that by using the above strategy, I can increase the twigginess of the tree by about 50-75% each season.

Spring Flushes

We are finally getting consistently warm temperatures, so my trees are really starting to move. Looking at them gives me a reminder that I have a lot of work to do 🙂 Sorry for the busy background… bad camera settings.

Dwarf Japanese Yew

Korean Hornbeam

Juniperus squamata ‘Blue Alps’

Ginkgo. If only the leaves would stay this size!

Ginkgo wire removed

This is the first spring where I am having trouble keeping up with the needed work on my trees. I am planning on doing some (more) culling on my collection soon, but much of that depends on the survival rate of my newly collected yamadori. I don’t have a huge collection (40-50 trees), but giving every tree the attention they need really takes a lot of time.

In the meantime, I am busy as hell. A friend was nice enough to remove the wire from my Ginkgo  for me 🙂 As a side note, this guy also has an amazing collection of fine mame and shohin sized pots and is always selling/buying. If you are looking for nice small pots, check out his website: Mame & Shohin Bonsai Pots.

As for the Ginkgo, many of the branches sprang back once the wire was removed. Kind of expected. Ginkgo is tough to wire because it scars so easily. Last year I wired it in late October and took off the wire yesterday (April 30). The branches seemed to have set better than in the past where I have wired it in March and had to take the wire off by early June.

I still haven't decided on a front for this tree. I think this side is more attractive, but the apex leans slightly back (it was not designed as the intended front by previous owners).

I think this is the original front of the tree, but I don't like the two symmetrical lumps about 1/3rd up the tree. They never used to bother me, but then my friend's wife pointed out that they look like bull testicles. Now that's all I see!

Ginkgo biloba ‘Mariken’ Air Layer

This is a very dwarf and dense variety of Ginkgo that I picked up at a specialized nursery for a good price. I keep telling myself that I will not buy nursery material unless it is exceptional but it is tough to live by this rule!

Ginkgo biloba 'Mariken'. If the layer is successful, this tree will quickly develop into a simple but attractive shohin.

Anyway, like most dwarf conifers, this specimen is grafted  – and the graft is very ugly. I knew this when I bought it, so air layering was definitely part of the plan.

Graft showing massive reverse taper below the bulge.

I have air layered a number of trees successfully in the past, and normally start the process in the late spring after the leaves have just hardened off. Of course, there is more than one way to do things in bonsai, and Graham Potter made a video which does a great job of summarizing his approach to air layering. The video can be watched here.

A summary of the key points of his process is as follows:

  • Start the layer in the early spring, when the tree is just beginning to show signs of activity.
  • Cut away a ring of bark, and scrape away all of the white phloem tissue until you have reached the sapwood below
  • Clean cut the top of the ring with a sharp knife
  • Rooting hormone doesn’t really help
  • Pack the sphagnum moss tightly against the trunk. Good contact between the moss and the trunk is important.

I am keen to try Graham’s approach, because starting the layer as early as possible will give it more time to develop in our short growing season.

The one time I tried a Ginkgo air layer, it failed. The tree bridged the ring wound – probably because I did not scrape away the phloem. When I re-opened the wound, the tree died. However, I know that Ginkgo are conducive to air layering because a friend of mine has layered a pretty chunky branch of a specimen Ginkgo yard tree.

The ring wound after scraping away the white phloem tissue.

The completed layer, packed tight up against the trunk.

Hopefully this tree continues to bud out and shows some roots soon!

Ginkgo is Early… Time to Repot

Today is March 12th, and my Ginkgo is already showing green buds. This means it is the ideal time to repot. This is more than one month earlier than I am accustomed to seeing movement on this tree.

The last time I repotted this tree was in 2010, and it was not until April 17th that the buds were starting to move! This seems to be the same throughout the bonsai community… a warm winter means early spring.

I am happy spring is here, but I am always concerned about taking my trees out of winter storage, then having to shuffle them around again when it becomes -15C in April 🙂

The ground is already thawed so I pulled out my ginkgo and brought it to a Toronto Bonsai Society meeting.

Normally I don't see this sort of action on this tree until mid-late April!

This is the new pot, which I got on a recent trip to Japan. It is probably 20-30 years old, based on the patina that is starting to develop. The shiny blue glaze has begun to relax into a complex, matte colour which I absolutely love.

The pot has no stamp on it. Nevertheless, it is a very high quality pot... heavy, but with thin walls. It will have no problem standing up to Canadian winters.

The tips of the shoots are just turning green, and the tips of the roots are just turning white. This tells me its a good time to repot.

All done! I think the new pot is a very nice fit. The old one was great too, and I was happy with it for 3 years. But I think its time for a change. This pot will really make the fall colours pop (unlike the last one) and is also suitable for the winter image. Can't wait for fall!