We hear a lot lately about planting trees and shrubs in the existing soil without amending a small circle because the roots will be reluctant to grow beyond the amended soil into the often less-fertile soil beyond. The caveat is that if the native soil is awful, you can replace it with something suitable - but that involves digging a large hole to accommodate future root growth. So, to get to my question . . . would amending a fairly large area of sandy soil with sphagnum peat moss (say a 4-foot circumference by a foot or more deep be a good idea to conserve moisture for Japanese maples while, at the same time providing good drainage? I found this online: Japanese maples do well in most types of soil. I recommend a loose media; consisting 40% fine silt or sand (usually your native soil), 20% peat moss and 40% organic compost. This mix will provide good drainage combined with good water and nutrient holding capacity. I'm trying to advise my son-in-law how to prepare his garden for 4 Japanese maples. We've gotten along pretty well up until now so don't want to steer him wrong.
Keep it sandy. Stay away from peat. Stay away from silt and high clay content. Plant on a mound. Bark mulch will reduce water loss to evaporation. Over time it will enrich the sandy loam and increase its moisture retention without suffocating the roots. Roots must have oxygen to live = drainage to create air-filled porosity. Too much water = no air = dying roots. Hence sandy soil on a mound. Mulch.
Once again, very sound advice. The only doubt I have is "Plant on a mound" : to me, that is not necessary in sandy soil, I would consider it for clay soils that retains a lot of water. Or if the mound is mulch, then I totally, fully, 100% agree : it will slowly release organic matter and since J. maples usually have roots close to the surface, it will keep them healthy. ;-)
Hi @Mani, it is important to plant maples slightly higher than you may think. Most of us plant so that we can see the root flare which is just below the main trunk of the tree. Also although it is written that Maples like moist roots, a lot of people mistake this with WET. . Do not get confused with moist and wet, the latter will cause root rot over time if the roots are not allowed to dry out and BREATH. So when planting, ensure a very loose mix to allow oxygen to the roots, this will give a maple every chance of success. Imagine where these trees do well in Japan, they are in a loose shale like soil on mountain sides. JM are shallow rooters for a reason, they evolved to grow well in very little soil, not with soil half way up the trunk as I have often seen done. Roots near the surface can breath. Maples are so often planted deep in their pots by garden centres and nurseries, so when you get it home you plant it in soil up to where you see the so called professionals have planted it. Do not do this, remove the soil from around the trunk of the tree and plant so that you can see the top root. You will be surprised and shocked at how shallow the hole needs to be. But the caveat is, make the hole square and two and a half times the size of the pot. When I plant in September, I prune the roots below and a little above to encourage fine new roots to spread. I then cover my soil with a thin bark mulch to stop too much evaporation. Or you can keep the roots as they are and create a slight mound to plant your maple, this will ensure your tree does not sit in a puddle of water. I have over the years done both ways of planting and either way has worked for me. Hope that is of some help Mani.
What I meant is to create a landscape berm of sandy (even rocky, possibly) soil into which you plant your maple.
