Pines first, then everything to bed

There is a version of fall on the bonsai bench that is nothing but putting things away, and it is the version that costs you the following year. The trees are slowing down; it feels like the work should too. But a black pine's next spring is set by what is done to its needles in the next six weeks, a juniper holds a wire best in exactly this window, and a deciduous tree shows you its real structure for the first time since April the day the leaves come off. Then there is the part that actually is putting things away, and it has one rule that people get backwards every year. So: pines first, then everything to bed. This is the order I work in, on a central Kentucky calendar.

Where we are

Zone 6b. First frost lands around the twentieth to twenty-fifth of October — the hive post used the same date — and the first hard freeze, the kind that takes the ground, around the middle of November. Leaves come off between those two. Nights have been under fifty degrees for a couple of weeks already, which matters for one group of trees before anything else.

Three things stop in September and stay stopped. No high-nitrogen feed after the start of the month — a tree pushed into soft growth now carries that growth, unhardened, into the freeze. A low-nitrogen fall feed is fine until the leaves turn and the conifers slow, and then nothing. No repotting. There are species and climates where a fall repot works; a temperate tree in a pot in 6b, with eight weeks until the ground freezes, is not one of them, and the root work waits for the buds swelling in March. No heavy pruning. The tree spent the summer putting sugar into its roots and trunk for exactly this, and large cuts now open wounds that sit unhealed through the winter. Light work, yes — and that is what the rest of this is.

Tropicals: already in

If you keep a ficus, a jade, a Fukien tea or anything else that does not know what a winter is, it came inside when the nights first dipped under fifty, which was late September here. If it did not, do it today; one frost is the end of it. Under lights, away from the heating vent, watered less than it was outside and misted more than feels necessary. They are the only trees on the bench that come indoors, and the reason is the subject of the last section.

Pines first

Mid October into November is the black pine's main appointment of the year, and the work is done with your fingers. Pull last year's needles — the older, duller pairs further back on each shoot — entirely, by holding the shoot and drawing them off backwards. That opens the interior to light, which is what keeps the inner buds alive, and it is what makes the tree look like a pine instead of a bottle brush. Then thin this year's needles on the strong shoots, the ones at the top and the ends of the branches, down to a smaller number of pairs, and leave the weak shoots low and inside alone or nearly so. The exact counts vary by teacher — six, eight, ten, twelve pairs, with a different number for each strength — and the principle does not: strong gets fewer, weak keeps more. A pine grows where it has needles, so needle count is how you tell it where to grow next year, and fall is when it listens.

A tree that was decandled in June has, by now, two or three small second-flush shoots at every terminal where the spring candle was cut. Reduce them to two, the pair that sit most sideways to each other, and pull the one pointing straight up or straight down. Then, with the tree open and the shoots short, this is the easiest moment of the year to wire a pine: you can see the branch, the needles are out of the way, and nothing is going to swell for five months. Wire, set the pads, and leave it.

Junipers: wire while it is hard

A juniper's growth has hardened by October, which is why this is the wiring window — the branches take a bend without the bark lifting the way it does on soft summer growth, and the wire sits through the winter and spring while the tree sets. Thin the strongest runners lightly, clean the dead interior foliage out with your fingers, and then stop: a juniper goes into winter with its foliage, because the foliage is where it stores what it needs to come out of winter, and a heavy fall thinning is the most reliable way to lose one in April with no idea why. The big foliage work is a summer job.

Deciduous: wait for the leaves, then look

Until the leaves colour, the only job on a maple, an elm or a hornbeam is to keep the fall feed going and the water steady. Then they drop — late October to mid November here — and for the first time since spring you can see what you have. Walk round it. This is when you find the crossing branch, the bar branch, the one that has been hiding the trunk line all summer, and the inverse taper that a leaf canopy flatters. Note them; cut lightly. Small cuts, removing a shoot here and a crossing twig there, are fine. The structural cut — the big branch that has to go — waits for late winter, when the wound has a few weeks of healing before growth starts rather than four months of sitting open, and when you have had all winter to be sure. Wiring a deciduous tree after leaf drop works and is worth doing, with one eye on the buds, which are set now and are what the wire crushes if it is laid carelessly.

And do the bench hygiene while the trees are bare: pull the weeds and the liverwort off the soil surface, rake the dead needles and leaves out of the pots, look for scale on the pines while you are working the needles. If you find it, the oil goes on in the first mild week of March, not now — the scale post has the calendar and the reasons, and nothing about fall changes them.

Then everything to bed

Here is the rule people get backwards. A hardy tree needs the cold. A maple, a pine, a juniper, an elm — these trees are built to go dormant, and dormancy is not a state they can skip: a temperate tree kept warm through winter does not rest, burns what it stored, and comes out of spring weak or does not come out of it at all. So the question for winter is never "how do I keep this tree warm". It is "how do I keep this tree cold enough to sleep while stopping the two things that actually kill a tree in a pot" — which are not cold, but freeze–thaw cycles in the root mass and drying wind. A tree in the ground has a metre of earth buffering its roots; a tree in a pot has an inch of ceramic. Protect the roots and leave the tree in the weather.

The simplest version is a bed of shredded bark or leaves on the north side of a building, the pots sunk to their rims and the mulch pulled over the soil surface. The wall takes the wind and the winter sun — a bright February afternoon on a south wall is what tricks a tree into waking early — and the mulch holds the root mass at a steady temperature a few degrees either side of freezing while the air does what it likes. A cold frame does the same with a lid, for the coldest weeks, with the lid propped open a crack and taken off on mild days, because a shut frame on a sunny day cooks. An unheated garage or shed with a window works for the trees that are least hardy in a pot, with the same caution about it getting warm.

Timing: after leaf drop and after a few frosts, which here is the middle to the end of November. Not before. A tree moved into protection in October, still in leaf, has not gone dormant and will not go properly; the frosts are what put it to sleep, and it needs to feel them. Once they are in, the winter job is a monthly walk: water the pots that have thawed and dried out — a dormant tree still transpires, and a pot frozen dry is a dead tree in March — check for mice and voles in the mulch, check the frame lid, and otherwise leave them alone. The trees will not look like much. That is the sign it is working.

None of this is difficult, and most of it is restraint: not feeding, not repotting, not cutting the big branch, not thinning the juniper, not bringing the maple into the kitchen because it looks cold. The pines get the one active job, and the rest of the bench gets looked at properly, tidied, and put somewhere it can sleep. Do that, and the hard part of next year is already done.