I too feel that a dull Japanese Maple still has great color when compared to other trees. But I think we can all agree that some years, the colors are much better than others. I thought the article covers the science well, but it is general; i.e. not specific to any one variety of tree. But much of the science still applies to our Japanese maples. It does provides a good understanding of the science behind the colors and what is needed for optimal peak colors. So I felt it was worth posting, because some may have not seen it before. I agree that the timing of visible color and peak color is different every year, maybe they are referring to the nights reaching the threshold value, starting the process, happens at the same time each year. But environmental factors can speed up or slow down the color display, as mentioned later in the article.
I agree with Emery. In Westonbirt (to take an example of grey, dull weather ;-)), Japanese maples color well irrespective of weather (albeit with some differences between the species which I will not develop here). On the other hand North American maples show strong dependance on conditions as described in the article. Concerning the timing, I recall that the main trigger for the initiation of Fall leaf senescence in deciduous plants is daylight duration (in fact plants actually monitor darkness), this is then modulated, in a way that is genetically coded, by low night temperatures. This modulation is variable among species. To remain with maples, I am sure we have all noticed that some of our trees are pretty much constant in their timing showing little impact of temperatures (in my garden I see this in acer cappadocicum var sinicum) while other species (A. palmatum is a good example) show a stronger temperature dependence. Gomero
Regarding dull weather and color... I found this fall to be very interesting, because of the contrasting weather. The beginning of October was abundant sunshine, somewhat dry and windless, with cool frost free nights. In my garden (my collection is made up of A. palmatum, A. shirasawanum, and A. japonicum) the varieties of Japanese maples that are always the first to turn and hit peak color in early to mid-October (such as 'Koto no ito'. It’s always the first to let me know fall has arrived) put on an excellent fall display. The second half of October was impacted by strong weather systems. That consisted of two weeks of overcast skies, much warmer than usual during the day and night compliments of overcast skies and a Southern breeze. Then the abundant rain came. Just as one weather system moved through slowly, completely saturating the ground, we had a two day break of overcast skies. Then Sandy hit the NE bringing us another round of abundant rain. We had over 8" of rain the last week of October. As a result, all the Japanese Maples that always put on a great show in late October and early November were very dull. And what was even more odd was many varieties, including 'Seiryu', turned Yellow. My 'Seiryu' is always a dependable red at peak with some little hints of purple at the tips. But this year the end of fall was oddly yellow with the only reds being the Japanese maples that are red all season (like Emperor I for example). That is great insight. I love to learn the how and why, or understanding how things work. Thank you for sharing.
Interesting that they say reddish rather than red. Covers quite a broad spectrum, which would include the plant I pictured also. Yes. Only in some locations does the Fall color turn a brilliant red. More of a shade of an orange cast scarlet red in most years, seldom is a crimson red but can be. I've seen it turn crimson in the Fall in Aurora and once in Gresham, Oregon. The biggest problem is that Villa Taranto and Red Pygmy have been sold as being each other quite often in Oregon. Some of us had to really search to find the right plant for each above name. The old Red Pygmy stock plant at Henderson Experimental Gardens never turned golden tones in the Fall. The Villa Taranto by contrast always turned golden to light orange tones (never strong orange tones) with intermittent red splashes in some years in the Fall. [A purist approach propagators special: years ago it was felt that grafting Red Pygmy onto a green amoenum rootstock hurt the overall red coloration of the Red Pygmy over time. Essentially, with continued grafting onto green seedling amoenum in Oregon and elsewhere the intense red color became noticeably washed out over time. Was not nearly the same reduced color effect when grafting onto green palmatum or green matsumurae rootstock.] As far as a bonafide red Maple in the Spring that turns yellow tones in the Fall we can fall back on the Maple that gave Koidzumi fits and that has been referred to in Vertrees second edition book as Ornatum (European Maple) but the plant that Koidzumi saw, after unified translations of the 1911 manuscript, was in fact the Japanese counterpart Maple Sotoyama instead. I've had both Maples and they are different by the leaf shape and lobe structure. The much finer leaf, the more feathery, is the Sotoyama. The longer length lobed leaf and the thicker lobes is the Ornatum. Both will turn yellow tones around here in the Fall. Neither turns orange like the Maple shown in the second edition Vertrees book. So in effect seeing a palmatipartitum or an linearilobum go from red in the Spring to golden tones in the Fall is not out of bounds at all but is not a characteristic of Red Pygmy. Jim
Hi Jim, Thanks for sharing such great information and experience. I suspected that the two red pygmy that I have were very much like Villa Taranto. Now that you shared your experience, it makes perfect sense. The tree I gave my parents from another grower demonstrates the characteristics of Red Pygmy, so it was hard to let it go. But it went to a good home. We kept the two that are probably Villa Taranto because my wife wanted Bamboo by the patio and the two trees I kept resembled bamboo, so it kept my wife happy and kept bamboo out of my yard (which kept me happy).
