Author: chogan@directresearch.com

 

The set-up:  Yardwork postponed is yardwork delayed.

I would have gone done a bunch of gardening tasks yesterday morning, were it not for the fact that there was a bunch of guys building a fence in my back yard.

I didn’t invite them.  The house across my back fence was torn down a couple of months back.  That old house has been replaced by a new, much bigger, house.  The builders of that new, much bigger, house are now tearing down the rotting fence between our yards, and replacing it.

It’s their fence.  It was falling down.  No one will mourn the loss.

But while that work crew is there, I’m not comfortable going out and engaging in a leisure-time activity like gardening.

I have dug a foot in his boots.  Or something.

That said, I can see that to make the post holes, they have a guy with a post-hole digger.  A manual post-hole digger, as pictured above.

Unsurprisingly — to me, anyway — he’s having a hard time of it.  The look on his face is about the same as the look on mine, when I try to dig holes in that area, using a post-hole digger.  It’s a cross between “you’re kidding me, right” and “I have to hack my way through this with a post-hole digger”?

The dirt in that area is packed with roots of every size and description, from 60-year-old-maples to the neighbor’s bamboo.  No single tool will do the complete job of making a hole in that.  (OK,a utility company truck with a power augur would likely have no trouble.  But not much short of that.)  I resort to (and dull the edges of) an entire array of tools when I dig there, starting with an axe.

In short, digging a nice neat hole in that location is going to be a total pain.

I do not envy the man his job.  I share his pain.

But he powered on through it, I guess, as the fence is now up.

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Vegetative propagation.

Now that fence is in, I need to plant something that will plausibly block my view of the new, much bigger, house.

I ideally want to plant something that doesn’t require a big hole.   Not in that location.  And yet isn’t tiny, implying years before it grows adequately to fill the space.

And if the builder plants his side in the meantime, I need to leave an open gap there for sunlight. So I may want to plant nothing.  At the least, this argues against buying a big expensive plant for this location.

In any case, I decided to use this odd need — it boils down to wanting a big plant in a small container — as an excuse to try out vegetative propagation to grow some new plants.

Old-school, this would have been stated as “I’m taking some cuttings”.  But to me, that doesn’t sound quite macho enough.  So vegetative propagation it is.

I’m trying to grow new skip laurels (and some new fig trees) from cuttings.  And I’m trying two methods of vegetative propagation:  Air layering some branches, and (what I think of as) snip, dip-and-stick on some twigs.  I vaguely believe the first is a form of brown-wood propagation, the latter is a form of green-wood propagation.  But I am unsure.  I’ve never done any of this before, and I have no clue about much of anything yet.  Let alone the accepted nomenclature.

Air layering.

With air layering, you intentionally girdle a small branch, hoping to force it to grow roots where you girdled it.  You cleanly remove a tube of bark about 1″ long, circling the branch.  Scrape the inch of branch to bare wood, optionally dust the wound with Rootone (or equivalent rooting hormone), pack a wad of wet potting soil around the wound.  Tightly wrap that wad in a layer of plastic.  Finish with a layer of aluminum foil.  The plastic is there to retain water.  The tin foil, to exclude light.

Note that, implied in all this is the idea of a branch with bark you can easily remove.  Likely second-year (possibly later) wood, with brown bark.  Likely not first-year green-barked shoots.  Thus, as practiced, an example of brown-wood vegetative reproduction.

Why not do this to a big tree limb, and produce yourself a brand-new big tree in one year?   I’m not sure.  I’m guessing the practical upper limit is set by the imbalance between leaf area and roots.  So I’d guess there’s a practical upper limit to how big a branch would survive this to become a new plant.  I’d say the norm is to do this on two-year-old wood.

Edit:  Upon reflection, that’s probably not the right reason.  Seems like leaf area and water transmission area should be in balance on the growing plant, no matter what age or diameter the branch is.  Each branch or stem would itself be balanced in this regard.  Maybe the limitation on survival is elsewhere, such as the point in time where the branch must survive on its own (new) roots.

In any case, then you wait.  Check your wad o’ dirt weekly.  Add water as required.

In a month, you’ll have a ball of roots running through that potting soil.  So they  say.

If all goes well, you then cut the air-layered branch just below the root ball, and hey presto, the branch is now a sapling.  Pot it up with TLC for one year, put it in the ground the next.   

Snip, dip, and stick.

With snip-dip-stick, you snip off a green branch end, dip the cut end in an inch or so of Rootone (-equivalent) powdered rooting agent, then stick that into a few inches of wet potting soil, in a flower pot.  Keep the pot well watered and out of direct sunlight.  Reduce to just a leaf or two per snip, so that they don’t dry out.

The theory is that (some of) these snips will grow roots in a month, at which time they can be pulled from the communal flower pot and potted up individually.  My dozen or so snips are sharing a north-facing, well-watered, never-in-the-sun flower pot.  Easy enough to water one pot.

As with the air-layered plant, they should remain potted up for a year, with TLC, and then should be ready to put in the ground next year.

In the end, these are two different ways to create something to plant next year.   I have no clue whether either method will work for me.  I’ll know more in a couple of weeks.

Addendum:  Why doesn’t air-layering kill the branch?

Here’s the part that could not believe: Girdling does not kill the branch.  The air-layered branches — stripped of their living bark for an inch — appear fine.  On both sides of the complete break in the bark.

Really?  I always heard that doing this to the trunk of a tree would kill it. And, it will.  But I figured that, by analogy, if you did that to a branch of a tree, the branch would necessarily die.

That turns out to be an incorrect analogy.  The leaves on the girdled, air-layered branches in my back yard remain green. All the way out to the end of the branch.  This is presumably from water transported to the leaves via the pith (inside) of the stem. 

Which, in my ignorance, I didn’t realize was a thing.  I thought all transport was via the cambium, the growth layer just under the bark.  But that’s wrong.  At the branch tips, water and nutrients flow from roots to leaves via the branch central pith, and finished products of photosynthesis (starches, sugars, and so on) flow from leaves to roots via the surface cambium layer.

Again, so they say.  I skipped biology in school.  Seems true, as those air-layered branches appear undisturbed by this approach.

The key point is that the branch won’t die for lack of water, even as you are preparing it for full independence from the mother plant.  That’s because you leave the water-distribution vasculature of the branch — the stem pith — intact.  Meanwhile, it takes the energy of photosynthesis, nutrients from the tree roots, and uses that to produce new roots, at the break in the outer bark.

At least, that’s the theory.  I’m reserving judgment, but this seems like an obviously better approach than snip-dip-stick.  I should know, for these plants, in a couple of weeks.