I'm planning to move a few newly purchased Japanese maples from the plastic nursery containers to some large wooden containers that I'm building. I have a few questions that I hoped I could get help with. Apologies in advance if I should have found them by searching but I tried and couldn't. 1 - is there a recommended recipe for a JM soil mix for containers? 2- is early fall an ok time to migrate containers? 3 - any instructions /recommendations on migrating containers? Should I loosen the root ball? 4- I was considering a fairly open wooden container that had a fabric planter bag inside. Do JM maples do well with fabric planter bags? Thanks again.
@Southernwayfarer good morning J. My mix is very loose, almost an alpine mix to allow for really good drainage. I use compost for mature plants, in the UK it is called John Innes no 3. I add horticultural grit, pine potting bark, perlite and a little peat. Quantities of each are 50% compost, 20% potting bark, 20% grit and the rest made up with the peat and perlite. Autumn is a very good time to repot IMO. I always do mine in September. I loosen the root ball, and trim the excess roots. I would be wary of fabric liners, as this can hold a lot of water and you do not want your maples sitting in puddles, as this will more often than not cause the death of the tree. Fabric planters that are not placed in pots are absolutely fine. It is the placing inside another container that is my concern. Good drainage is everything with Japanese maples. Hope this is of some help J.
I’ve got some medium-sized trees in containers. I used cementboard type planters with added drainage holes. My wood planters drained too quickly and out the sides. Here’s my mix. It’s been working well for a few years near Seattle. I just kind of came up with it from reading lots of blogs. Not sure if it’s the best but it works for me. It’s fast draining. 3 parts potting soil (no manure) 2 parts small pine bark nuggets 1 part pumice (1/8 size) Some other things I learned: You’ll need to root prune every couple of years to keep them happy. They like snug fitting containers. Make sure the containers are on feet not on the ground. Develop a watering system. I made my own sprinkler to help evenly distribute water. I used square containers to kind of experiment and see if it’ll reduce circular roots. I’ll know more in the early spring. The Shishigashira is 7+ feet. It’s lots of fun. :)
