leaf size reduction

[thailand-steve]

hi all, how do you get smaller leaves (to get the sense of big tree scaled down) on bonsai trees?

i believe this is caused by root pruning right? but how does that process work?

if i'm taking a normal, say 5 year old tree with already fairly well developed leaves, then i start pruning the roots and putting it in a bonsai pot, what happens? i assume i would trim off most of the original small branches so most of the original leaves would eventually be gone, but what about the new emerging leaves, post root trim? do they somehow know to grow small because the roots are constricted?

what is a typical time line for the leaf shrinking process?

i have a banyan tree and i'm not ready to put it in a bonsai pot yet, i'm still thickening up the trunk, but is there anything i should be doing now to keep the leaves small or should i just net nature do its thing?

thanks

 

[KennedyMarx]

When growing material out you don't want to reduce the leaf size. That will cause the tree to take longer to grow out. First get your trunk to the size you desire, then work out your branching, then you worry about leaf size. With a banyan (an exception being the ficus benjamina) you can completely defoliate a healthy tree and the leaves will grow back smaller. Depending on climate you might be able to defoliate several times a year, which is what I suspect you can do where you live.

 

[thailand-steve]

When growing material out you don't want to reduce the leaf size. That will cause the tree to take longer to grow out. First get your trunk to the size you desire, then work out your branching, then you worry about leaf size. With a banyan (an exception being the ficus benjamina) you can completely defoliate a healthy tree and the leaves will grow back smaller. Depending on climate you might be able to defoliate several times a year, which is what I suspect you can do where you live.

thanks. and the process by which they grow back smaller? is that determined by root pruning?

overall, i think what you are saying is let the tree grow naturally (either in the ground or in a big pot) and only when it reaches the final trunk/branch size you want, do all the pruning and shaping and move it into a bonsai pot, etc. then when its in the bonsai pot, focus on styling but don't expect much additional thickness. is that your advice?

 

[KennedyMarx]

Yeah. Root pruning doesn't really have anything to do with leaf size. Roots are pruned so that the plant can continue growing healthily without suffering from compacted roots. If the roots hit the wall of the pot and can't grow the top growth will slow. That's why container growth isn't as strong as in ground growing.

 

[thailand-steve]

i just found this on u-tube http://www.youtube.com/watch?v=T_RVXxT6N0g

that guy has a lot of good videos, i'm going through them all

anyhow, he says that defoliating is a good way to reduce leaf size, the new leaves grow back smaller

 

[nairb]

I always wondered about this as well, I once saw a horse chestnut tree as a bonsai, I was amazed the leaves were about the same size of the palm of my hand, whereas in a free growing tree they can be 30cm across!
Won't you be affecting the health of a tree if you defoliate it every year (or several times a year?)

 

[Paradox]

Thailand-steve,

Welcome to the forum. Lots of good info and people here

I would suggest you try using the search function on the forums and reading through the threads in the maples section of the board. All of your questions have been answered before.

I also recommend you find some basic books on bonsai to start learning some of the basics. If you have a particular interest in maples, then the book 'Bonsai with Japanese Maples' by Peter Adams is very good if you can get it.

 

[Poink88]

In my experience there are 3 factors that influence the leaf size tremendously.

1. Tree health. Stressed tree may produce smaller leaves because that is all it can produce. Not good IMHO. FREQUENT defoliation MAY result to this. Healthy leaves should also be more efficient and less area (see below) would be needed.

2. Leaf quantity. Trees usually need a certain capacity of photosynthesis. Whether it is done by 50 big leaves or 500 small leaves, doesn't matter. It is like having a target photosynthetic square footage (area) to maintain the tree. A highly ramified tree can have that 500 smaller leaves. Defoliation can help get there....so does pinching.

3. Sun/light exposure. A leaf under shade cannot photosynthesize as much as one in full sun. It is not operating at 100% efficiency. Tree will respond by producing bigger leaves to compensate.

Find a good balance between these 3 and you will be golden. JMHO

 

[KennedyMarx]

i just found this on u-tube http://www.youtube.com/watch?v=T_RVXxT6N0g

that guy has a lot of good videos, i'm going through them all

anyhow, he says that defoliating is a good way to reduce leaf size, the new leaves grow back smaller

Yeah, Paul's videos are some of the best instructional bonsai videos on youtube. His advice helped me out tremendously. Be sure that the species you're using can be defoliated without dying. Junipers, boxwood, pines, and some other types of trees will die back or just die altogether without foliage.