For the past few days, we’ve been graced with warm weather in Boston, and today I decided to capitalize on it by getting started on some late-winter work. Unfortunately, I’ll be losing access to the garden plot where I keep most of my pre-bonsai material, probably in the next year or so. This means plenty of trees to be potted over the next season or two, and a bunch of new plants outside my apartment. Lots of work, but on the upside, no more battling with the rabbits that constantly chomp away indiscriminately at new shoots.
Here’s the sunny garden last season, mid-summer. The nicest pre-bonsai material was salvaged from renovated gardens. Other trees were collected from under power-lines and near parks where volunteer plants shoot up and are fought back every season. One or two trees came from a nursery.
Today I’ll be potting up 6 trees of various sizes. I’m satisfied with the trunk thickness on all of these trees, so I’ll be potting them in plastic training containers with a homemade soil mix. It’s a straightforward 1:1:1 mix of Turface (a material used for baseball fields), pine bark mulch, and poultry grit. It seems that people have had success with this mix across a range of species. This brand of bark is a little on the large size, and I’ve been looking for something finer.
This is my first year mixing my own soil. I tracked down these ingredients in MA, north of Boston, and I’ll list them below for anyone in the area looking to save money by mixing their own soil:
Turface – sold at Northeast Nursery Contractor Center, 6 Dearborn Road, Peabody, MA, 01960
Pine Bark Mulch – sold at Mahoney’s, 242 Cambridge Street, Winchester, MA 01890 (There are many locations in MA)
Poultry Grit – sold at Tractor Supply Co., 82 Turnpike Rd, Ipswich, MA 01938 (There are a few locations in MA). Make sure to get the Poultry Grit and not the Chic Grit, which is much smaller.
I’ve found that there’s not much small particulate matter to sift out of this mix, so a quick rinse of the thoroughly mixed soil will suffice. I’ve read that the rinse water can actually be sprayed on plants as a mechanical pesticide.
For containers, I’ll be using plastic nursery pots, cut down in height and lined on the bottom with landscape fabric. I find this easier than cutting individual screens for each opening.
The weeping forsythia (Forsythia suspensa) above began as an air layer from a large shrub. I used sphagnum moss for the layer and had great success growing prodigious roots after only a few months. I removed and planted the layer in late summer. The plant grew strongly and put out multiple shoots through fall.
After digging it up, I’m amazed with the amount of roots this layer had grown. You can see where I originally cut the trunk back to a side branch, and again higher up. Although I’d planned on growing the trunk out thicker, I decided to keep the tree on the smaller side and work on the branching instead.
In the image on the right, you can see the flatness of the bottom of the root structure. Strong lateral root growth was developed by planting the layer directly over a kitchen tile, which forced new roots to grow outward.
After I carefully remove most of the existing soil with a chopstick, I re-arrange the roots to ensure that they will grow radially and not cross each other. The tree is potted in premixed soil, and air spaces under and between roots are filled by gently probing with the chopstick. Finally, the tree is watered thoroughly and a little extra soil is added to cover the tender new roots near the base.
A note on using sphagnum moss–while it encourages vigorous root growth, when I uprooted the layer, I noticed that the new roots that would become the visible nebari were tightly integrated with the moss and each other, and required delicate untangling. It’s possible that removing some of the moss before planting the layer would have saved lots of heartache later on..
Potted up, you see the strong shoot growth from last season. I’m very satisfied with this layer, with the exception of the large scar on the left side of the trunk. Hopefully, the cambium will roll over a bit more and hide the wound before it must be carved or preserved later on.
This tiny red oak (Quercus rubra) was collected in 2013 from a granite slope where it had grown for many years. despite its age, it came away easily in a single dry mat of moss and roots. Unfortunately, after I planted it out, a summer drought killed of most of the tree. I left it alone for a few seasons as it struggled to come back to life. Today, it consists of a few small shoots on a gnarled trunk, so I figure it’s time to throw it in a pot and see if it has more luck recovering.
It’s not the prettiest tree. It’s barely even a tree at all, but I’m hoping that if it can recover, I’ll grow some branches and keep it as a small winter bonsai.
The witch-hazel above (Hamamelis virginiana) is in a similar situation to the oak. I transplanted this weed mid summer, at the worst possible time. Most of the upper tree died back but by late fall, a few new shoots had developed. The base of the tree has a very interesting, gnarled trunk.
Potted up, you can see the thick base. The only living shoots are barely noticeable, but I’m hoping that this tree will bounce back and grow some branches. Like the oak above, the leaves of this species are difficult to reduce and will look completely out of proportion on a small tree. However, witch-hazels bloom in winter, and can make a very attractive winter trees. Both of these trees are really just experiments.
Another witch-hazel, this one with a twisting clump of trunks. This one has better branching, but a strange taper.
After cleaning the roots and examining the trunks, I decide to break them apart and see if I can get a few trees out of one. Alas, only one of the trunks produces a useable tree. This one still has a bit of strange taper, but much better branching. It will probably need some carving to get rid of the weird lump below the first branches.
On to a more respectable tree. This azalea (Rhododendron ‘White Lace’) was rescued last spring from a garden on Beacon Hill where I estimate it had lived happily for at least ten years. It was chopped back to its major branches, but recovered well thorough the summer, growing new shoots from all over.
Once I clean the roots, I am extremely happy to find a very developed nebari that had been buried initially. I think this tree has a lot of potential. It has a major scar along the front of the trunk where a branch must have broken off. The wound is probably quite old and has healed well, but will need additional carving in order to look more natural. It might also be necessary to remove the first major branch and leave a deadwood feature, or remove it all together and leave a long, curving trunk. Either way, it will take a fair amount of sitting and staring before I decide to do anything.
The final tree of the day teaches me yet another lesson. This common winterberry (Ilex verticillata) was purchased from a nursery in the spring of 2012 and left to grow for a few years, during which time it doubled in height and thickened considerable.
I’m satisfied with the thickness of the trunk, so I decided to pot it up. Right away I notice that the rootball is an incredibly dense lump of feeder roots, all tangled together. I remove much of the root mass and it takes me about an hour to untangle the roots that I’ll be using. A few thick roots have been wrapped around the base of the trunk–a fairly common occurrence with nursery plants–and must be removed. It takes altogether too much time to work on these roots. Next time I plant out a nursery tree, I’ll sort the roots beforehand, to save a fair amount of sweat later on.
I chop the trunk so that the remaining tree is approximately 2/3 of the finished height. This tree needs lots of work. Free from the thick roots wrapped around the base, a new nebari must be developed from the smaller roots beneath. The large deadwood protrusion, that was initially buried, must be ground back. Finally, the large trunk scar must be carved or left to heal further. This is very, very raw material, but exciting nonetheless.
Overall, a successful day of potting with many surprises, both good and bad. During the next few months, I’ll be potting up another round of plants from the garden, so stay tuned!
Thanks for reading,