Hi Elizabeth
Two feet tall planted in Spring 2006 getting root bound in a year and a half (with some dormant months) in something like 30 gallon pot. May be I don't have experience like this yet so I think of it as unbelievably fast to get root bound in such a big pot.
I was expecting mine in a five gallons pot for a long time (with root pruning sometimes later).

You should bare-root your potted trees occasionally... especially if you feel they are root bound.  If you pot-up your tree without removing the old growing mix, you run the risk of the original mix compacting as the roots grow through it and grow larger.  This can cause the roots to girdle and prevent nutrient flow between the top and bottom of the tree.

A 2' tree in a 25-30 gallon container is excessive.  Especially if you are considering planting the tree in the ground anytime in the next five years.  If the trunk of your tree is less than 3/4-1" in diameter, a 3-5 gallon container will be more than enough to hold your tree for the next few years.  Currently I have five trees which are 6+feet tall with trunk calipers in excess of 1 1/4 inches growing in either 3 gallon nursery pots or five gallon white buckets.  All of these I will bump up to a 15 gallon container next year, and will probably stay in that size containers for at least 3 years. 

My guess is that your trees are not root bound in a 25 gallon container after 2 years.  Just the same, if you'd like to root prune, you can cut out two pie shape wedges about 1/6th (total of 1/3) of the container and remove the growing mix and roots and replace with fresh growing mix.  Next year take out another 2 sections and the next year the last 2 sections.  Your tree will be completely root pruned every three years.  Another solution is to get a 1 - 1.5 inch copper pipe and drive it down into your growing mix in several places.  You could punch 2-3 holes per month during the growing season.

~james

James
Would you please elaborate on "Another solution is to get a 1 - 1.5 inch copper pipe and drive it down into your growing mix in several places.  You could punch 2-3 holes per month during the growing season."
What is the purpose of the holes? Is it to make holes in the root ball cutting the roots with the pipe edges? Is it like lawn aeration to take out soil plugs for air and nutrients to go in? Should the holes be filled with soil?
Thanks in anticipation of your response.

Root-pruning serves two purposes... 1) you remove larger inefficient, or damaged, or deformed, or circling roots.  2) you remove old growing mix which no longer possess the original quality.  Whereas it is relatively easy to bare-root a tree, as they get older it becomes increasingly difficult and cumbersome to do so.

Punching holes will both sever the roots in the area as well as aerate the growing mix.  If you imagine a circle with a radius of about half the radius of the container, you would want to concentrate outside of this circle during the growing season.  You don't want to eliminate the punches inside the circle (closer to the trunk), just punch not so frequently.  Then as the season starts winding down (or just before the growing season starts) you can focus a bit more inside the circle.  By punching over time and in different areas you are continually root pruning your tree while minimizing the shock normally associated with doing so.

If the growing mix is relatively new and still has the qualities you are looking for, you can put it back into the holes.  Otherwise, put new growing mix in.  This really isn't too different than cutting pie shaped segments out, only that it is being spread out over time.  Either way, you want to remove about 1/3 of the volume per year.

Thank you James. That explains it very well.
That gives me an idea to sharpen the edge of a copper pipe & probably make tiny teeth at the edge so that there is easy penetration in the soil and sharp cut of the root without messing the root system (but then, as usual, I will not be able to find my tool when I need it !).

Elizabeth,

I'm not sure what your climate is like.  Among my trees I have  9 that are growing in 4/5 gallon buckets in what is now basically compressed vermiculite and 1/2" granite chips.  The  They survived at least 4 days in a row of temperatures either approaching or exceeding 100°F without being watered.  

a 3 year old Alma in 4 gallon bucket


This is the smallest of the trees I described above.  You can see how much the growing mix has collapsed, yet it is okay without water for a few days... even the hottest of days in Houston.  My 25g containers which hold trees with 3+ inch caliper trunks can go a week without much of a problem.

I still have reservations about the volume of your container and the mix you are growing your trees in.  It maybe that your growing mix is holding too much water which is preventing root growth into the bottom of the container.  What are you growing your trees in?  How big is the tree now (both height and trunk diameter)?

~james

 Bought some trees this year & root pruned 3/4 of the roots from 2 gallon pot in april. The plants have girdled the pots tightly. My root pruned trees did very well & gave me more than a dozen fruits. They are about 5 to 6 feet tall and I used 5 gal pots. Again in late Sept I got a celeste twig(green) pulled from the ground with probably about five roots thats about one cm long and its leafing now. I pruned the top off & left about 2 inches of the cutting above dirt. I will be root prunning my other newly acquired trees in March 2008 & to check for any nematodes lurking around. My experience has been fig trees are hardy to abuse in root pruning and all my handyman's work on root prunning are information others have shared on Fig Forum Garden Web.

You guys, root pruning goes so much easier using a good 'ol handsaw. I pull the tree out of the pot and set in on some newspaper. I proceed to square off the root ball by sawing four sides off about 1-2 inches deep depending on size of the pot. Then I try to round out the root ball by sawing away the corners if the square I created.  I turn the tree on it's side and cut off the bottom at the same depth. I replace with potting soil in the bottom of the pot, same amount I removed. Then place the tree back in the pot and fill in the gaps around the rootball with potting soil but water as you go to settle the medium.
Hope this helps.

Leon,

When do you normally root prune, late winter or early spring ? thanks.

Paul

Here you are root pruning photos. They aren't of figs but it is equally valid to illustrate it.

With this technique, we remove 3/4" of each root ball side, bottom included. The new root ball is introduced in the pot (We don't change the pot) and we add new potting soil in the sides but not on the bottom. The volume of soil removed from the bottom is added on the top, so we will stimulate to the fig to grow new roots in this zone. It is similar to above mentioned techniques.

As far as I know, this technique is used with bonsais (sorry, I am not a bonsai expert).

Axier -- picture says alot. Thanks. Would used the illustrated methodology in root pruning my figs. Saves alot of time over the "sissie" manner I was doing in root prunning my figs.

As I mentioned before, there is a benefit to removing all of the growing mix from the roots.  On Saturday, I encountered my third hard core in a root ball.  The tree was growing in a three gallon nursery container.  It is clear it started in a smaller container and was potted up without root pruning. 

There is only so much volume in a container for your trees to grow in.  Over time the growing mix breaks down and looses its porosity.  At the same time, the tree is producing new roots and the existing roots are fattening up, thereby occupying more of the space inside the container.  Over time the entire mass hardens making it difficult for new roots to grow into it.  The older, fatter, brown roots become less efficient at moisture and nutrients.  Thus the need for root-pruning.    Replace the growing mix with a more porous mix and removing inefficient, large roots to make room for the more efficient, white, fine roots.

The problem, over time, with the pruning method Leon and Axier have laid out is they don't completely remove the growing mix.  Eventually the volume occupied by the old growing mix becomes unusable to the tree.   So let's say one cuts two inches off of a root ball growing in a 3g container.  The volume of a 3g container (10D X 12H) is about 950 cubic inches.  If you cut the diameter down by two inches (8D X 12H), you end up with a root ball which occupies 600 cubic inches.  This leaves about 350 cubic inches for your tree to grow into until the next root pruning.  As it turns, a 1g nursery container is about 300 cubic inches.  Would you plant a 5' tall fig tree in a 1g container?

Having said all that, I don't think that Elizabeth's problem will be solved by root pruning.  It would seem that one of two things is happening with her containers.  She could have a very fast draining growing mix and not enough water stays in the upper portion of the container.  However, if this were the case the roots would grow down to where the water is, as mine have.  How many times have we seen people post their roots were poking out of the drain holes within a couple of months?  What are we talking about 10-12 inch tall containers in two months time?  Surely, in 2 years time the roots could make it to the bottom of an 18 inch tall container.   So this scenario seems unlikely.  The same holds true for insufficient water volume during watering.

Given my experience and the little bit of information given, what does seem likely is that the growing mix is retaining too much moisture, thereby creating an environment which does not allow for root penetration.  If you combine this with the sun warming up the top couple of inches of growing mix to a temperature above what is conducive to root growth, you end up with only a small percentage of the container volume being utilized by the tree.

One way to find out is to dig up the tree and check the amount of root growth.  A tree in a container for two years should have a substantial root mass.  Another way to check is to drill holes big enough to stick a finger into.  The next time the tree is wilting the day after being watered, start drilling.  Begin at the bottom and work your way up.  Note where the growing mix is sopping wet, where it is very wet, where it is moist and where it is dry.  If I were a betting person, I'd wager it will be wet higher than you would expect.

~james

Is there any need to root prune if a tree is in the ground?

I would have to do this copper pipe technique rather than dig it up, obviously.

Just planted the trees a few weeks ago. They are just 2' tall with calipers of 1/2" to 3/4". So I'm thinking into the future here.

--------

Also, some of the trees were a bit root-bound in their small 4" square x 8" tall nursery containers. Out of ignorance, I didn't loosen their rootballs too much before planting. But now they're in the wide open ground... So will they correct that themselves?

I'm in zone 9, Northern California.

Norcalfran it was answered here


http://figs4funforum.websitetoolbox.com/post/need-to-confine-roots-to-get-fruit-6816231?pid=1282045188#post1282045188

Thanks. Sorry for the duplication!

Relax, no need to prune and no worry the way you started in ground from a 4" pot if it looks healthy in the ground at this time.
Sometimes people root prune trees in the ground to slow down the growth and make it behave like a dwarf tree.  Such pruning is done by pushing shovel in the ground to some depth in a circle around the trunk at some distance from the trunk. Sometimes it works and other times the vigour stays depending on the roots habit of the tree if shallow or deep.

Elizabeth, vermiculite holds a lot of water.  You might be better off with perlite and 1/3rd compost.  Letting the roots grow into the ground is a good thing.