Let’s talk Dawn redwood. During this stage of my bonsai addiction, Dawn Redwood is the front runner as my favorite. What strategy are you using for Primary Developement (controlling roots)? These trees have very aggressive roots and grow straight out the bottom of my 3 gallon nursery pots into a raised bed. Theyre going on a bench for the time being. How are you creating radial roots without having to fight those aggressive “tap” roots? Anyone tried different air pruning pots or a unique method of field growing (dread the day I dig those up). Bonsai On! Thanks in advance.
I had some smaller ones in wood boxes with a mesh bottom and that seemed to keep the roots in check. In the ground, I would use a shallow grow bag (depth about 1/2 the diameter) and remove it from the bag for root pruning every 2 to 3 years. That is what I do with Acer campestre (hedge or field maple) which also has roots that end up with 2 or 3 dominating if not constantly kept in check.
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A wood box is my method. I generally need to repot every year to straighten the roots and trim them back. Here are a few from repotting time.
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Great job with the roots. I also like to use a wood box once they get a little size (smaller seedlings dry to fast).
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Very cool, and thank you for sharing. I am engineering some treated air pruning boxes to keep the roots from twirling. I am going to work on the base layer tonight and send some photos. I love these trees but these roots are truly on another level. Wood boxes are so customizable. Artist best friend.
I’ll send photos of my air pruning box for DR. Hopefully can get some traction with it and be able to form nebari and manage swirling roots.
2 x2 foot interior boxes. Bottom will be raised up 3.5 inches sitting on 4-5 perpendicular 4x4s. An 18x18 tile will be placed in box on top of growing medium then the tree planted on top of tile to encourage lateral growth of roots. This is a big ol air pruner 1.0 for Dawn redwood. The fine screen will have several 1 inch holes courtesy of my blow torch.
Nice work, watch that fine screening to make sure it doesn’t get clogged. I found a picture of my boxes. I can crank them out pretty fast. I use cedar boards and 1/4” wire on the bottom.
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Very nice. The plan for these trees is to get some 5-6 footers. The fine mesh will have some one inch holes maybe 5 or 6 one inch holes per 2x2 square for roots to escape. I’ll use a blow torch to make the holes in fine mesh. October is going to be all Dawn Redwood.
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I make my grow boxes from cedar fence boards that are nominally 5/8" (16 mm) thick. I use 1/8" (3 mm) wire mesh in the bottoms for all sizes. They drain very well and air prune the roots in the bottom. I also use mitered corners and sides sloped at about 12 degrees since they look better in my opinion. The picture shows 6", 8", 10", and 14" (15, 20, 25, and 35 cm) outside dimension boxes. Because they drain so well and I have fairly hot, dry summers the trees need to have fairly decent roots before they go into the boxes. An exception seems to be Acer campestre (hedge or field maple) that can go into the 6" boxes with weak to moderate roots and do well.
this thread has made me seriously reconsider the method I went with… #2 soil bag in ground… haha this also explains why its pushing 6’! I planned on popping it out in once dormant for winter greenhousing (Mid Coast Maine). Maybe this is something I do in the Summer?
I have really liked the photos and suggestions! Thanks all!
Good to hear they grow well in the ground in a bag. I would wait until at least early fall to pull it from the ground. If you just plan to dig the bag you can wait until leaf drop. But if you plan to cut off the bag and do any sort of root work I would do it a couple of weeks before leaf drop so it could start to push new roots. I would wait to do the chop until just after leaf drop so it has stored as much energy as possible, but still has some in the trunk to start to close off the wound.
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