Catalpa bignonioides 'Nana'

[kiwi1958]

Hello…I am writing this post from the US. I don’t know much about trees so please forgive me if I am not clear. I have a dwarf Catalpa tree (Catalpa bignonioides 'Nana') that is 4 years old. The first 3 years it did beautifully. Last winter was extremely harsh with very low freezing temperatures. The tree survived but grew erratically and seemed to have gone “wild”. Once it started blooming in spring, it started sprouting all over the trunk which I snipped off. Then the whole top (ball) and existing branches did not sprout at all. So the tree started sprouting new branches from within and under the ball…. it grew all out of shape. The branches grew so fast and the leaves got so huge, some 10x their size, that in a heavy wind, the branches would break off because the wood was not hard enough yet. During the summer I cut of the dead wood and cut the branches back to form the ball again and also to take the weight off the new branches. The tree and leaves never took the shape like in previous years….just grew wild branches and huge leaves. My question is to all you experts is….once this spring comes, should I prune the new branches back down into a ball again like the shape it was when I first bought the tree? And… if so, will the tree ever take on its beautiful shape again and leaves their normal size again? I am so disappointed as here in the states this catalpa is hard to find, took me years to find. I got so many compliments on it….any help/advice would be appreciated…

[Chris at eden]

It sounds like the cold weather has killed of the terminal buds. Those are the one on the end of the branches. These buds secrete chemicals called indole auxins which basically supress the growth of secondary (side) branches. This is known as apical dominance or apical control. If you cut them off the side growth will grow unchecked and the same will happen if the frost kills them.

 

If you continue to cut it back it will re-start the process of this wild growth as you refer to it. This is actually a valid way to grow Catalpa as it forces the tree to put on larger leaves but it wont flower and wont really be tree shaped. I have a jungle garden so I cut mine down to about 4 feet every spring so I get these big leaves.

 

If you want it as more of a tree you will need to regrow the canopy. allow it to grow for a season and then when you prune it, select out the best leaders to create the canopy shape you want. Don't reduce the leader at all. To begin with it will still throw out side shoot but just keep trimming these off. Allow the side branches to develop on the new leaders. Eventually the buds on these new leaders should produce enough chemical to take over the apical dominance role.

 

It may always be a bit misshapen and multi stemmed and will take a while to reform as you want it. Catalpa is also pretty sensitive to wind and possible frost but don't quote me on that last point. As such you should always plant them in a sheltered position.

 

Hope this helps,

[daltontrees]

It could hardly have been said better.

[Paul Barton]

Agreed - great post Chris.

[kiwi1958]

Chris....thank you so much for your reply!!! it was very well stated and understandable. Now I have some idea how to get my tree back! Let me interpret back what I understood.

 

1. I have attached a link to show how I WAS going to prune the tree this spring....but from my understanding you are telling me NOT to prune it in this manner.... if you scroll down, you can see the tree leafed out..this is what my tree used to look like

 

2. The tree has grown for a season as you stated...so this spring what I am to do is pick these leader branches...allow any smaller branches to grow from the leader branches and snip off any other shoots that grow from the ball/trunk of the tree.

 

Question.. (this tree is at our second home 4 hours away, so I am not able to see it at this point or send pics) When I do prune the tree, can I cut the leader branches back just a bit to shape it into a ball as illustrated in the second link I have attached? In this illustration, I see the leader branches and the little branches that come off of them...this is what I need to achieve?

 

Pruned Tree: Catalpa Bignonioides Nana Trompetboom Snoeien Pruning Indian Bean Tree Pictures

 

Illustration: CNLA - Canadian Nursery Landscape Association: G. Deciduous Trees

 

Thank you again for this wonderful advice !!

[nepia]

kiwi, there is hope for you! I had a semi-mature specimen in the garden that was so shaded by other trees, and hence weak, that I pollarded it at 11ft from the ground leaving just 3 large limb stubs. That was in 1997.

I dealt with the shading/crowding by the other trees around and didn't touch the Catalpa again until I sadly had to clear it up after last winter's storms wrecked it (it split down the main stem).

My point is that when the storm hit the tree was 45ft tall with an even crown that had the outline of an egg sitting on its fat end: it was the best tree in the garden!

A slight caveat to my optimism is that the reason the stem split last winter was due to an inherent weakness in the form of an included union, i.e. an enclosed region containing bark from both major limb and trunk that had allowed rot to develop. This is very common in trees and often a cause of weakness but don't let it detract from your own long-term plans. Catalpa is a great tree - native to your country - so the best of luck with it.

 

Jon

[kiwi1958]

Jon....thank you so much for your interest and reply.

 

Since this is a dwarf Catalpa, known for its beautiful globe shape, after a brutal winter it took on characteristics of a normal Catalpa! I thought it went wild.

 

So I posted in hopes that this wasn't true....and that with the right pruning and patience... it would once again regain its globe appearance.

 

Thank you for your story!!

 

Kiwi...

[treequip]

I am afraid I may be the bearer of bad tidings

 

What was said above is all perfectly correct and valid BUT "nana" is grafted, that is the ball top characteristic is joined to a standard catalpa stem.

 

The ball top part is a naturally occurring variance that is all part of natures trial and error system, the fact that the entire top didn't grow, and the stem did leads me to suspect that the graft has died and the only growth was coming from the root stock

 

The reasons for this could be that the grafted material is a bit on the soft side and simply couldn't stand the cold, similarly a bad graft could have suffered from frost damage.

 

I am afraid you are in a wait and see situation, the re growth in the crown might be from the grafted material, if it is, in time you will get your tree back, if not and you cant live with the results, I would cull it and start again. For the here and now the growth on the stem is putting energy back into the system so I would leave it on for now, it can always be removed later if the grafted material makes a come back

 

I have seen several quite large grafted catalpa where the entire top had died off above the graft, that was also attributed to cold.

[David Humphries]

Hello Kiwi,

 

here's an little anecdotal story & observation around Catalpa to help enthuse some hope.......

 

This specimen developed a significant fault in the main union from a strong wind event.

 

We were really only left with two options, fell & chip it or 'sensitively' reduce it

 

The subsequent 'reduction' was not really in line with our British Standards to be honest,

(although an update in the annexe which regards to the needs of poultry, should be a serious consideration)

but apparantly the chickens who were enjoying the shade directly below it were not too keen on waiting for a replacement to mature and provide a similar service

 

So with the the right growing conditions (and possibly a whole heap of chicken waste) the species appears that it can be vigorous and produce a reiterated and fairly globular canopy in very little time

 

a periodic hair cut should keep it in order

 

 

.

[nepia]

I am afraid I may be the bearer of bad tidings

 

What was said above is all perfectly correct and valid BUT "nana" is grafted, that is the ball top characteristic is joined to a standard catalpa stem.

 

 

My bad. At least the OP enjoyed my non-Nana story!