Ok got it, just gonna let it do its thing for now. I’ll prob just stick with a repot later and cut anything really bad off like you said. Just started bonsai this year, so all my stuff is a lot younger lol. Got some of my favorite trees thickening out for the next 5-10 years lol. I think you’re near me, any recommendations on cool species that can easily tolerate our zone?
Hornbeams - Carpinus caroliniana is excellent, but a little touchy about dehydration, it will not tolerate drying out. Part shade suites it well. Ostrya virginiana, the hop flowered hornbeam is a species seldom seen for bonsai, which I think is excellent. Hop flowered hornbeam tolerates a more sun, and dryer conditions than Carpinus caroliniana. However both hornbeams are trees of moist deciduous forests, getting too dry will be fatal. Both are hardy into zone 5a or 4b, fully hardy in the greater Chicago area.
Elms, any and all elm species are good bonsai. Locally the American elm used to be common, but Dutch elm disease has wiped most of them out. If you find young trees, they are worth a try as the DED mainly affects trees taller than 15 feet. Our trees in pots are not overly susceptible. Chinese elm, the cultivars common in bonsai cultivation are all hardy through zone 5, and are ecellent. I am fond of the Ulmus chinensis cultivar 'Seijiu' for bonsai.
Siberian elm, Ulmus pumilia, the invasive species that seems to be everywhere is actually pretty good for bonsai. It must have full sun or it will drop branches on the shaded side of the tree. But leaves reduce well, branches ramify well, bark is rugged and fissured, overall a good elm.
Slippery elm, Ulmus rubra is native to the area, also rock elm, Ulmus thomasii though rock elm is more common in Wisconsin, both are excellent. Slippery elm is somewhat shade tolerant, all other elms prefer full sun. I wish rock elm, Ulmus thomasii was easier for me to find, I have not worked with it, just admired trees in southwestern Wisconsin, its common in the driftless areas, west of Madison.
Pines are a cult in themselves. For starters try mugo, Pinus mugo and Scots pine, Pinus sylvestris as locally very winter hardy with no tricks to learn. I had nice success with a Jack Pine, Pinus banksiana, for a number of years. It was a grafted short needled variety that was developing nicely. I sold it a while back. Notice I have not recommended either of the Japanese pines. This is because the Japanese black pine is not quite winter hardy here, it will need winter protection if it is growing in a container. And Japanese white pine, while technically hardy through zone 4, seedlings are often poorly colored with many bad traits, and nice select cultivars their hardiness depends entirely on the root stock chosen. Both Japanese pines can be grown here, but need a cult like attention to details and winter protection, a cold frame or greenhouse or other protection.
Thuja occidentalis, white cedar or arborvitae is excellent, and fully hardy. There are many cultivars, and since they do root from cuttings, you are not dealing with grafts as you would be with pine cultivars. Also try Hinoki cypress, Chamaecyparis obtusa, Hinoki are a little more tender, the two species otherwise require nearly identical care.
We are at the northern limit for Japanese maples, they need to be covered or protected in winter here. The native red maple Acer rubra is pretty good for medium to larger bonsai and fully hardy. Sugar maples and Norway maples have leaves that are just too big, and don't respond well to container growing. Silver maples lack the key charm of most maples, autumn color, so avoid silver maples. Red maple is the best locally native maple. On west coast is the vine maple, but it is not quite winter hardy here.
Genus Malus, any of the apples, crab apples, all make good bonsai, nearly all types are hardy through zone 5. Related, I liked Amelanchier, the serviceberry, except serviceberry has been slow to "trunk up", it tends to stay a thin trunked tree. Apples, pears, cherries, peaches and plums all make decent bonsai, most of the culinary fruits are hardy through zone 5. You can start them from seed harvested from fruit for eating or purchase grafted cultivars through nurseries. Seedlings grow fast, though apples may take upwards of 2 decades to start blooming regularly from seed. Most culinary fruit trees respond well to air layering, so you can purchase a named grafted variety and air layer off a branch or two to make smaller or mid size bonsai with guaranteed fruiting characteristics.
Juniper chinensis cultivars are a must in any bonsai collection. 'Shimpaku', 'Itoigawa' and 'Kishu' are the best cultivars for bonsai. Disease free, and essentially botanical silly putty, can take any shape you want. Avoid the Juniperus virginiana, eastern red cedar, as it is disease prone (cedar-apple rust) and it is difficult to get foliage to tighten up to nice foliage pads. There are a few good ERC bonsai, but they are rare.
Actually check out what is sold at your local landscape nurseries, most of those species are good for bonsai in one way or another. A walk in the woods is also a good "species list" for trees hardy locally. Look for trees with smaller leaves and a feature of interest, like fall color, or fruit or flowers. Avoid species with big leaves like grapes, etc.
As you get more confident in your horticulture skills, try American persimmon, Diospyros virginiana. It is fully winter hardy here, I love the fruits, though to some they are an acquired taste. They are touchy about repotting, many loose their persimmons shortly after repotting, so they are not a beginner tree. But if you have access to seed, or trees, they are worth a try.
, so wait for leaf drop to assess structure, if bad then make structural cuts and if it’s good then downsize pot. Also repot in spring to assess roots and work on nebari. Correct? If the main ascending branches are good then what size pot should I aim for? And also what exactly should I be looking for to decide whether to cut or keep them?
