Posted 05/04/2012 I've just been given a flagpole cherry blossom tree, and I'm trying to decide where to plant it. My best option is in the back corner of the garden, which would put it about 4 or 5 feet out from the back wall, and 4-5 feet in from the side wall.
Posted 18/04/2012 That sounds fine. My mature (20+ year old) cherry blossom has roots stretching about 3-4 foot along the ground at its base. As long as you plant it about 4-5 foot as you said from the boundary there shouldn't be a problem.
If your tree was a large one I might plant it closer into the garden because neighbours can be annoyed by overhanging branches from trees but seeing as it’s a flagpole cherry blossom I don't see that as a problem! Also I'm pretty sure that given the fact that they are so skinny then they would have fewer roots above the ground than rounder cherry blossoms.
Here are some links about planting trees – the second is a video.
Also don't plant it any deeper than the pot it's in as that could kill it. In fact many of the experts recommend building a mound (a tiny 'mound', you're talking about 1 inch higher than the ground level) so that the tree roots can spread happily and the trunk doesn't get rot. Think about it - if you're wandering through a forest you have to constantly dodge roots from healthy mature trees so it's only natural that the roots grow a bit above ground. Planting it higher isn’t strictly necessary (and can be awkward if you’ve never done it) but definitely don’t plant it lower.
Dig a hole that is at least 3 times the width of the container
it's in so that the soil is loosened up to allow the tree to anchor itself more quickly (some experts recommend a square hole so that the tree’s roots won’t go round in circles). Dig in a bit of powdered/pelleted/granular fertiliser such as blood fish and bone.
Some people line the base of their big planting hole with thick brown cardboard or newspaper (not glossy magazines) so that it absorbs moisture and stops the tree from drying out so quickly. The cardboard will rot into the soil after a few years so you don’t have to worry about litter in the soil.
You will definitely need to stake the tree (see the links) to stop it from getting blown over/rocked in the wind.
Give it a mulch (spread a layer over the top) of good compost to feed the soil and then some bark mulch if you like to stop water evaporating from the soil below and to stop weeds from forming and stealing the tree's nutrients. Don’t bother to feed it after that until the following year because overfeeding can actually kill a plant – I’ve learned the hard way – nearly killed a crabapple from being too nice to it and then making it get a magnesium deficiency from too much nitrogen. Cherry blossoms though delicate looking when in flower are actually pretty tough so they’ll adapt to the soil you have.
Lastly and most importantly remember to water your tree. Young trees need plenty of water to establish themselves. I know we live in Ireland and you can take for granted that the rain will water them but it is very important to water it thoroughly (at least 2 buckets/watering cans) at least once a week and maybe more often on sunny weeks until it drops its leaves in autumn.