My understanding is that the red on the Sangu Kaku and most other coral bark varieties exists on the new growth only but that cold can intensify the color where present. Is this accurate? I ask because I've seen Sangu Kaku at the nurseries aged a few years with the coral color a third or more of the way down the main trunk(s). And it sure looks like more than the new growth is red. So what gives? Also I read somewhere that Beni Kawa is notable because the red bark persists on the second year shoots. 1. Is that true? 2. Is it true that the other Coral Bark's red does NOT persist on the 2nd year shoots?
In my experience the color lasts for 3 years or more for both varieties (but it fades each year). There are some other issues that we must consider with how far back the color shows. I think exposure can cause the bark to callus over (sorta) and show the grayish brown color rather than the red. This is not necessarily a bad thing in my opinion, however, as most of these coral barks (particularly sango kaku) succumb easily to pseudomonas and possibly winter injury partly due (IMO) to the very thin bark. I guess what I'm saying is: the beautiful bark color is probably a weakness for a tree's defense mechanism. At the nursery I work at the most beautiful color specimens are the quickest to show damage in spring from which ever one of these problems does the damage. We see more of it in nursery conditions because they are completely exposed, so I would suggest putting any coral bark in a partially protected area. Some other smooth bark maples like Shishigashira show sunburn easily from this thin bark, but I have not seen evidence of pseudomonas.
More than one clone on the market as 'Sango kaku' as well. Recently I have noticed stock supplied by Monrovia to a local garden center as this cultivar is sporting apricot orange fall color, much more orange than usual.
Genetics clearly play a major role but for a given genome environmental and soil conditions could make a huge difference. One can see a field planted with hundreds of 'Sango kakus' at 'Pepinières Gaurrat' nursery and, there, all wood, including >5 years old trunks and branches, is a beautiful coral. I buy one of them and, at my place, after 2 years only the new growth is coral. This nursery is not far from my garden also in zone 8 with probably milder winters (they are closer to the Ocean). The main difference is that they have highly acidic soil and twice the rainfall I get. I am not drawing any conclusions, I just want to pinpoint how little we know about the processes involved with bark changing colors. Gomero
Ron B you raise a good point I have noticed some differences between the Monrovia Sango kaku and some others. My first though was that they were grown very fast (which I believe they were), and that environmental conditions played a large part. This may prove true but I intend to graft and compare the two I've seen for a few years to see if they indeed are different. In my experience the Monrovia selections I've seen have gone through the nice clear yellow, into gold and then into that apricotish color. In fact I was looking closely today and the interior leaves were as clear yellow as a ginkgo. The outer leaves are showing some orange tones though. Let me also mention as a side note that I have seen a nearly full grown sango kaku where there was almost no red stems showing because of its age. The annual growth had slowed to a couple of inches per year and only that showed any major bark color. The fall color was amazing though.
This Sangu kaku was purchased by the previous owner of our home from Home Depot. She planted it in a raised bed of almost pure compost. I've forgotten how old it is, I'll try and find out next time I talk with her. Maybe it's not showing as much bark color because the darn thing is too happy. It is growing by leaps and bounds. I found it interesting that at the point I took the photos, when I looked up from the base of the tree I could not see red branches or stems. But when I pulled a branch end off, I saw red on the top portion of the stems. Isn't that a feature of a different cultivar? Going off my spotty memory, isn't there a Sunrise and a Sunset - one has yellow on the bottom and red on the top and the other is the inverse? Which, come to think of it, I'd be happy if this tree were one or the other. I can find Sangu kaku of just about any size at just about any nursery. Oh, well. I enjoy the tree's fall color. And next Spring I'll shape it a little. I already took some off this fall (after the pics). And I'm sure I'll love the tree, no matter what cultivar it is or isn't.
I don't think that's a Sangu Kaku. The bark should be grey-brown on the trunk blending into the red stems - no green stems at all. The leaves also look way too big. Here's some pics of mine for comparison...
The redness varies with the season. It's a mistake to try to make cultivars as frozen in their characteristics as a piece of furniture. Apart from variations like individual specimens varying in pigmentation with the seasons and stage of growth, there is the influence of propagation method and site conditions. And an old, popular cultivar like 'Sango Kaku' may come to be represented over the years by numerous independent introductions. A friend found one with fruits on it one year and grew a batch of seedlings, a high percentage of which had red stems. This would seem to indicate a high likelihood of seedlings having been raised and put on the market as the cultivar many times.
Waka momiji red stem has the larger sized leaves than a standard Sango kaku has. The old form Sango kaku has, after leaf out, new growth leaves that are yellow green (aocha) at first with older growth being a light green. Beni kawa has noticeably darker green shaded colored leaves both in the flushes of new growth and as seen in the old growth by comparison. For us here only the later new Summer growth will show the lighter toned leaves on Beni kawa in most years. Currently, my Japanese Sunrise shows no pink, red or coral colored bark at all. Only the newer late Summer new growth shows some pink coloration in the petioles that will hold now that we have had some evening and morning cooling. Also, the last two flushes of new growth (the last flush is still expanding, has not come to a stop yet on the middle to lower portions of the tree) produced the lightest colored leaves of the season. The trunk will eventually color up to a nice red after we get some frosts here. I've seen no real red bark or red trunk color in this tree until January the last few years and then it turned allover red as soon as we got some sustained cold chill. I am in complete agreement with what Ron B posted above.. As with clonal variants in other plants, we can see some individual differences in population groups of Sango kaku. Look at block of 100 five gallon trees in a wholesale nursery or even in some retail nurseries and see an array of slight differences in leaf, bark and petiole color and sometimes differences in the numbers of lobes. Seedling selections of Sango kaku, Senkaki and Waka momiji red stem have been propagated and have been sold in Oregon since the early to mid 80's. The more commonly seen plant sold in Oregon as Sango kaku was a seedling selection from a Sango kaku parent plant. It was the vigor in the "new" tree when young that others felt made this selected seedling to be more desirable than the parent plant was for mass duplication. The survival rate of the grafted individuals was considered to be higher as well than the former Maple was. We may have slightly lost some color to the wood in some years with the new clone but we got a stronger growing plant as a result than the former Sango kaku parent line plants were, once they were planted in the landscape. The primary nursery standard landscape trees for Sango kaku in California are grafted progeny from the seedling raised clone that came out of Oregon. Jim
Although assumption that vegetatively propagated tree cultivars are all single clones (as opposed to cultivars of flowering annuals and annual vegetables, for instance, which when raised from seed and maintained by constant re-selection are obviously not single clones) this is not, in fact the case by any means - as Jim has related above. The longer and more widely a cultivar has been grown the greater the window of opportunity for multiple clones to have been put on the market under the same cultivar name. While it might seem that essentially duplicative introductions would usually instead get their own, new names in an attempt by the originator or introducer to differentiate them - and capitalize on them - a tendency to make use of the success of a well-established, already familiar name seems to be common. A result of this is independent introductions not necessarily closely similar to the true cultivar sometimes being marketed under the well-known name. In the case of the 'Bloodgood' maple we even have entire blocks of conspicuously variable seedlings being sold as the cultivar. Some stock offered here has not even been a good solid purple color, let alone that whichs offers the complete package.
