Aerial Roots on Ficus rubignosa

[closetbonsai]

Hi guys and girls of the internet bonsai community. I have recently repotted some neglected pj figs and have two questions.
1. What are peoples opinion on aerial roots and how do you control them?
I recently tied some twine around the trunk to pull the established aerial roots back toward the trunk for a more cascading effect.
2. what is the secret to good nebari (nice looking roots).
I find that some roots tend to swell up and look pretty disproportional to the size of tree. I have just cut them off leaving a bit of a scar and unfortunately some reverse taper.

[Jamie]

hi CB

good questions!

1. with airial roots depending on where they are coming from removal is generally key, especially if they are coming from branches as when they hit the soil and start taking up nutrients and water they will begin to thicken and also feeding that branch which will in turn get reverse taper. what is best is to let them grow some, enjoy them for a while then before they hit the ground you can trim them a few inches above soil level, that way you will still get the airial root look without gettig the problems. if they are coming of the trunk depending on how high up they are and thickness, if you can pull them in tight to the trunk they will fuse into the trunk, it has to be done early though, if they are left to thicken and are coming from high up the trunk you will get the reverse taper problem again.

2. figs and nebari are easy to build, you can use several methods to do this but to help with the best interests for yourself and the tree a picture of what your dealing with would be very handy some options are ground layer, air layer, toothpick methods, flat cut. but need to see the tree to help best

[Levuccio]

Hey Jamie

I heard ppl talking about reverse taper before....could you please elaborate on that?

Cheers

[Taffy]

CB, Levuccio - reverse taper is where a branch (or trunk) is thicker towards the end or higher up the trunk than it is where the branch exits the trunk or where the trunk exits the soil. With an aerial root coming from a branch, the root will feed the branch from that spot to the tip, so it will give it more nutrients than it will get from the trunk to the aerial root and the branch will thicken more.

Hope this quick sketch and the photo gives you an idea of what I'm trying to explain.

In the photo, the red arrows show the trunk is narrower at the bottom and the blue arrows show it's thicker further up.

Reverse Taper1.jpg

Junireversetaper.jpg

[Istari]

How would you correct the reverse taper if you wanted the airial to hit the ground and thicken?

[Taffy]

If you only have one aerial root growing from a branch, then over time it will thicken the branch - and I don't know of any method of containing it, except maybe to cut the branch off on the outer side of the root and hope it shoots from that spot. That way, you'd have a thinner branch from that point on - at least until the root took over and thickened it up again.

If you have aerial roots along the length of the branch - and you have branches and twigs coming off the main one for the full length of the branch, then reverse taper thickening isn't an issue because each aerial root will be feeding a different part of the branch.

It's too late for me to do it tonight, but I'll take a photo of a Port Jackson I have here that has aerial roots along the full length of the main branches and there is no reverse taper at all in them.

Actually, here is a photo taken a while ago of the tree that shows the roots at that time:

Branchroots.jpg

[Istari]

thanks mate you've given me good food for thought.

is there any techniques to devlop an airial root and thicken it up or is it all about time?

[Levuccio]

Thanks Tman, got it now!

As far as promoting aerial roots, from what I know they will grow in humid conditions, so if you are in northern queensland there shouldnt be a problem,
if not you can have a humidity tray during summer, and I even heard about ppl putting some king of plastic on top of the tree or something similar to
retain humidity and promote aerial root growth.

[Istari]

thanks levuccio, guess its worth a try

[Taffy]

Levuccio is right Istari.
In NSW, you'd have a job getting aerial roots to grow naturally. I lived in Penrith for nearly 10 years, but before that I lived in Darwin. Some of my figs had magnificent aerial roots on them when I got them down from Darwin to Sydney. Unfortunately, they came down in the middle of winter and not one root survived the change in climate. They all died, along with most of the trees.

The only way for you to get good aerial roots would be as Levuccio said and create a humid environment for the trees. The only problem then would be that they would also need protection in the winter. Any temps below zero will kill the roots off if left outside in the weathers.

Guys, I wouldn't worry about trying to get aerial roots on your figs in your climate. Don't forget, you can grow species down there that we don't have a hope in hell of growing up here.