I have an 8 foot high acer japonicum acontifolium with about a 10 foot spread. It is facing south but is under very large 80 year old street maples. It is planted in the midst of some large rhodos. It was transplanted from a large pot 4 years ago and has done "ok" since; my problem is that its leaves begin turning red way too early each year. They are actually beginning to turn red right now (July 4)! So, am I not giving it enough water? It was planted on a bit of a mound of soil so there would not be much ground water. But it also only gets early morning and late afternoon light. Any ideas why it would be turning red so early?
Hi Dragonfish: How are you currently watering your Aconitifolium? What method of watering are you using such as hose watering, sprinkler irrigation, drip irrigation or natural rainfall? If you are using a permanent irrigation system how often are you watering and about how much water is being applied to the tree? How much wind does your tree get? What is your soil type and how good is your drainage? Just basic questions but if you have Rhododendrons then the soil and drainage probably are not a big issue. How long are the leaves staying red in color once they turn red? How many leaves in relation to the other leaves are turning red and where on the tree are the leaves turning red? Top of the tree, new growth, old leaves, middle of the tree, just give me some idea as to what is going on. < It was planted on a bit of a mound of soil so there would not be much ground water. > It is this statement above that has me the most curious as to how you are watering your tree at the present time. I will say this now that Aconitifolium grown in deep shade can produce coloration to the leaves early in the season. Are the leaves turning color and then dropping off the tree soon and is there some dieback occurring in the twigs once the leaves drop off? Is there any new growth to come about in the areas on the tree where the leaves have turned color? I'll work with you, just give me something to "play" with. Jim
Hi Jim - thanks for the reply. Here goes a more in depth description... The tree gets plenty of rainfall here in Vancouver November - April. I usually start watering in May by leaving a hose on at low volume for 12-24 hours, every week or so. Usually once or twice a month I will also put on a lawn sprinkler to soak the whole area so that the rhodos get water too.The ground surrounding the tree is covered in naturally occuring moss and it is rare for the dirt below to ever get "bone dry." I would guess the soil is somewhat acidic, given how happy our rhodos are. For a few years we fertilized the rhodos with steer manure, though none was placed within three feet of the maple. We have a 5 meter blood good and a 4 meter acer circinatum located parallel to the acintifolium which are fine and don't color early. The acintifolium receives almost no wind, but for the odd windstorm. Your comment that "Aconitifolium grown in deep shade can produce coloration to the leaves early in the season." may be the issue. The tree is pretty much in shade all day from the trees above. There is die off each year of lower level branches, though there seems to be a nice bit of growth in the spring/early summer at the crown of the tree. I should perhaps mention that the tree has been stressed a bit the past few years by the caterpillars of the winter moth. This past winter I taped and glued up the street trees which killed the female moths; thus the infestation was quite reduced this year on my maple (50-100 caterpillars?). I killed the caterpillars by hand, but also sprayed the tree with "Safer's soap" diluted in water in the spring. Could the use of this insect control be an additional stressor for the tree? To sum up, I think the possible stressors could be: too little light, winter moth caterpillars, use of safer soap insecticide, improper watering. Of these, I most suspect the light issue. I wonder if I should pester the city to stem up the street trees higher? Also, should I perhaps dig a hole and insert a pipe to get water directly to the tree's roots? Someone told me that the tree may have been a bit root bound when I planted it and that this may mean the roots are not growing out as they should. Any advice you can provide is appreciated!
Hi Dragonfish: If you are concerned about whether you are watering enough, dig a hole sometime about 2 1/2' away from the trunk of the tree and check for moisture. At this point I am not so sure that your Maple is not getting adequate enough water. Deep shade is an issue but if your Bloodgood and your Circinatum are doing okay then possibly too much shade is not the big issue here. It would be nice to allow more light to come into the tree though. Were the leaves that turned color in areas where you had the insect infestation? I do not like using any sprays, even soaps on Maples from Spring to Fall. I feel there is a risk involved as I've seen Maples not respond well to sprays but sometimes we have to do it, depending on where we live and what factors are working against us. Root bound Maples can be a problem in heavy soils but if your Rhododendrons are happy the soil probably is not an issue at all. Even root bound Maples will start to initiate root growth relatively soon after they have been planted, unless they have been root bound for 5-6 years or so. I've seen root bound Maples for 10-15 years grown in containers grow out of their delicate state with a little helping hand at planting. Some people like to prune the roots, I prefer to knock off a lot of the old soil or untangle them to free the roots, giving them unimpeded room to grow and establish themselves in the ground. Some people with certain varieties of Maples want their plants to become root bound, just ask any Bonsai grower. Generally, in deep shade Maples will have their lowest leaves on the tree turn color first. I would be worried if grown in deep shade that my leaves on top of the tree turned color first. I've grown 'Green Cascade' and 'Meigetsu' in deep shade whereby the only light they would get was filtered morning sun until noon. It was foolish for me to plant them where I did but I wanted to grow them at a 5000 elevation and I could not be up there enough during the Summer to water them. So, I made a choice, plant them where they could eventually adapt to all of the water they would get between November and April with some intermittent watering from me on occasion or plant them in a location that gets much more sun and see them wither away into nothingness during the hot Summer. Even at that location it can get up to 100° in July and August. My price to pay for planting them in so much shade was that the lowest growth on the trees would color up first and in most cases die out on me but the top growth was okay for me. My reward was that I did get to see fantastic Fall color. Check your water and see how much moisture your tree is getting. Try to see if you can get more light into your tree. Once the low limbs die out prune them off when you know they are dead. As far as the insects, well, that may be a problem in the future but if you have to spray a soap go ahead as my biggest concern with soaps has been eliminated by you not being as warm as us and the fact that the soap will not be burned onto the leaves as they would be here. Your problem is not the soap at this point. More light is what I think you need the most for now. Tell me more about your tree if you can. Jim
