Hello, I'm very much a beginner gardener and I've bought an Acer Shirasawanum 'Aureum' for aesthetic reasons alone - My problem is I don't know what to do with it! The tree is between 1.5 and 2 ft tall at present. My garden is fairly small and my soil is largely clay-based (I live in the Clyde Valley in Scotland) which I believe makes it alkaline and perhaps therefore unsuited to the Acer (neutral or less pH seems to be required). The key questions I have are: 1 Is this type of soil totally unsuitable for the tree or would the tree/soil be adaptable? 2 How large will the tree grow - Can I control it's growth up/out by pruning? 3 Would the tree be happy in a large pot if my soil is not suitable - If so, for how long? Thanks in advance for any advice you can give me. Yours, Barry
Hello Barry, I don't think your soil would be unsuitable, but the plant you have is generally more fussy and more difficult to grow than many. We have to preface this with the idea that plants sold as Acer shirasawanum Aureum vary from place to place and likely from country to country. The implication is that you may have a cleaner or more tolerant variety than we commonly see here. All of that aside, I would still handle the plant with great care and consideration. I have attached a photo of my plant that has been growing in that pot for 3 years and I got it at about 3 years old. We can assume it is 6-8 years old and suffered one severe insult 2-3 years ago where much wood was lost. To have the plant recover has been a miracle. If you search this site, you might find some other photos of larger plants, but the growth rate is slow. Most of the plants I have seen up to about 10-15 years old are quite shrubby and will be 6-8ft tall and easily as wide. I have also seen forms of the plant grow well as single trunked trees up to great heights, but it is rare to see one survive to achieve such stature. I just remember a photo I took a couple of years ago and attached it, of a large tree at Greer Gardens in Eugene, Oregon. Its age is unknown to me, but I am sure there are some that might know when they got that plant. They have quite a few large decidious magnolias and a pair of very large Acer palmatum Seiryu that may have been planted within a few years of that tree by their comparative size. There are not many trees like the one in the second photo. So, what to do. I have seen dieback on mine before both from streess and a random branch lost to verticillium one spring. But since then it has done well. Since it is happy, I have decided to leave it in the pot for another year or two in pretty heavy shade to make it as strong as possilbe and then plant it out by breaking the pot--wanting the largest and strongest rootmass possible. The tree needs a well drained site and a neutrual pH from 7.2-6.8 would be fine, but a more alkaline soil could cause you problems. I would worry most about the clay and if you have a more cultivated area, I would plant there, or if you can work a small plot for a season or two with soil conditioners and acidifiers depending on your situation, the tree might benefit. When I say a plot, I don't mean a planting hole, but a larger area that would be appropriate to your garden size that would maintain drainage and water flow gradients, as amending a planting hole in clay is just making a basin. If your clay is relatively loose (we have a very compact type here) you might be able to plant right away, leaving 1/4-1/2 of the rootball exposed and then creating a large mound around it--heavily mulched. In any case, if potted with a good medium and fertilized lightly once a year, the plant will be fine in a container. It would prefer partial shade, or indrect filtered light. Direct sun in the hot part of the day for us here will fry the leaves. Your color on the plant will be best if given some sun. Sorry for the essay, but this is just a plant that is easy to write about and one worth the time if you can get it growing strong. ******Prune all you like, but pruning frequently and lightly during the growing season (after the first flush of growth has hardened) is best. Best regards,
Barry, I planted an Acer shirasawanum 'Aureum' which was about a 1 1/2 twig eleven years ago and it was one of my first maples ( I knew nothing about growing them). The area I wanted to plant it in was a lot like yours, clay (don't know about the ph). I improved the soil around it and planted it so that it was on sort of a "knob" which I hoped would work. It gets sun in the morning for about three hours and then is shaded in the afternoon. It's now about a six foot beautiful tree and one I am especially fond of it since it has stuck around all these years. Maybe by planting it somewhat high, you can do the same and not have to worry about the clay as much. Good luck with whatever you do. Kay Dye
