How do I tell when the seasons change? Especially the difference between Early/late periods.

[Azz]

How do you tell when the seasons change? People are always saying "do X in X season" but I am struggling to really learn when they happen.

For example I have read to bend junipers you do that in Fall. When in fall? I have heard early fall, and late fall. Ok, when are these? Is early fall before or after a few frosts? Is late fall before or after the first snow/trees having no leaves.

Same for spring and maples that wiring is done late winter/ early spring but when are these? before or after last frost, before the leaves come out? Etc.

There is a lot of info online and such and it can all be quite confusing/contradictory. Any help/guidance would be awesome. Even a basic layout of what weather/climate/tree signs to look for would be awesome.

 

[RoadManDenDron]

Each season is 3 months, the first is 'early the last is 'late'

I expect there is a little wiggle room over exactly when they start but also there is wiggle room in most tasks carried out

I prefer to look for signs in the tree for tasks to be done in that tree rather than signs in the weather such as bud swelling and re-potting

 

[Shibui]

Definitely watch for signs the trees give us. Tying work to calendar seasons doesn't work. Trees grow at different times in different places depending on the local climate so 'early fall' is not the same month in all places. Look for when trees start to bud up for leaves to open - that's spring. Look for when tree growth rates slow down - that's good enough for early Fall. When growth stops and leaves begin to turn that's late Fall. As you get some experience you should also be able to tie tree cycles to things like first frost, ground freeze, etc, etc.

I have heard early fall, and late fall.

You will find there's lots and lots of different opinions about what to do in bonsai and when to do it. At first it sounds really confusing and contradictory but I have come to see that one is not right and another wrong. In most cases all are right or part right. The times to perform each bonsai task is much wider than most growers realize so they stick to their own safe ideas and will not go outside that comfort zone. Of course it works but it's not the only way.
One of our problems is that we work in long cycles of years. It takes a long time to trial new ideas and then do enough trials to be sure.
Bonsai can be expensive so most growers are reluctant to try different things. We usually stick to what we know is safe.
Another issue is that we work with living plants that are affected by many different variables. We change one thing and assume the result is from that thing when maybe other changes we did not notice have affected the results. Many growers base their idea on just one trial which may or may not be valid.

In summary:
don't get too worried about specific times. Times to do bonsai tasks are wider than usually realized and will be different for each area.
when you see a range of opinions don't worry about who is right and who is wrong. Accept that these contradictions mean there's a range of right.
don't be afraid to try different things. That's a good way to learn.

 

[shinmai]

I have found it generally helpful to understand the seasonal life cycle of trees in the context of the solar calendar. Broadly speaking, the solstices and equinoxes are signposts, subject to a certain amount of wiggle room. Virtually all temperate [i.e., non-tropical] trees respond to changes in the length of the daylight interval, and there is a much lesser correlation to temperature.

As an example, the reason for repotting azaleas in late February or early March is that beginning around the time of the vernal equinox they awaken from dormancy and metabolic activity accelerates. Repotting before that starts gives the tree the maximum interval to grow strong roots before they blossom, summer temperatures arrive [coincidentally, around the summer solstice on June 21], and water uptake increases dramatically. The reason for bending certain species in fall is because as photosynthesis declines and water uptake decreases, branches are experiencing a much lower vascular flow—when the branches are less turgid, they become more flexible. Pruning and structural cutbacks on deciduous trees after leaf drop means the trees are done producing food—thus by cutting away material that won’t be part of the design, we don’t waste food resources on those unneeded parts in early spring, saving the sugars for the new growth that results from removing apical buds.

There is an old aphorism that states that the best day to go fishing is whatever day you can. I may, for example, perform a task a bit earlier or later than ideal if I need to travel for work, or visit an elderly parent in another state. [More than once, I’ve missed a repotting window, and something has lived in a nursery pot for another year, but next year will have a February just like this one did. ] As our friend Shibui rightly states, the windows are wider than much of the “expert” advice would have you rigidly believe.

My point really comes down to the idea that if you understand what your tree is doing seasonally apart from what we do to it as bonsai technique, and are observant of those seasonal changes, it becomes much clearer as to when something ought to be done. The first question should always be, what am I trying to accomplish, and the second should be, based on what this tree is doing as a living creature, is this the right time to ask it to do what I want to accomplish.

Just my two cents.