Starting to panic a bit

Michael T Mon Mar 23, 2015 12:08 pm

I repotted three very large Amur maples. Two of the three have leafed out. The third, my favorite, had several green buds just starting to swell. But it's been a week and they are not continuing to grow. They are green, but they have stayed the same size. It has spent a few days out in 60f weather with partial to full sun. And the balance of time in a sunroom.

For that tree, it was a pretty drastic root reduction. But there were four or five long roots with a fist full of fine feeder roots on the ends. They are planted in pure grit. And have been fed with deluted fertilizer.
I'm comparing this tree to the other two which began growing almost immediately. So I'm a bit panicked I killed it.

I'm wondering if it's unusual for maples to take a while to respond from a drastic pruning? Any experiences to share?

**JimLewis** Mon Mar 23, 2015 12:28 pm

Have patience. Your maple probably is fine. Trees leaf out at their own rate, and you probably shouldn't try to hurry them on.

augustine Mon Mar 23, 2015 5:07 pm

I'm with Jim, hang on. Amur Maple is very vigorous. Many of us have experienced this late blooming esp after a drastic root pruning.

Last year I had to remove a large circling root from a Hackberry. I didn't think it would present a problem since, number one, it was a Hackberry and, secondly, there were lots of fine roots remaining. However it did not leaf out. I left it out in the yard and continued to water when needed but lost hope. I was getting ready to toss it out when I noticed the buds were breaking, this was end of May. It was healthy all year and has lots of buds for this season.

Good luck and best regards to all,

Augustine

steveb Tue Mar 24, 2015 12:29 am

My tridents are leafing out as are my Japanese maples. My hedge maples and hackberries aren't. I wouldn't worry about it.

Michael T Tue Mar 24, 2015 3:45 am

Well, no change in appearance. So I decided to scrape the bark on a few branches. Green. Good sign I suppose. Guess I'll keep misting and watering and periodically light feeding. Nerve wracking. I'll try to post some pics. I think it could become a nice tree.

**Kevin S - Wisco Bonsai** Tue Mar 24, 2015 11:10 am

Michael T wrote:I'll try to post some pics. I think it could become a nice tree.

careful !!!
posting pics might put the jinx on it !!!

i, for one, would rather see a pic of it leafed out Wink

Richard S Tue Mar 24, 2015 5:26 pm

I'm no expert so take this as more of an open question than a definitive statement but...............you say you are feeding this tree?

Is feeding a freshly root pruned tree which hasn't yet leafed out and is experiencing temps of around 60' F a good idea?

Most advice given is to NOT feed freshly root pruned trees until about four weeks after they leaf out.

Not saying this is the cause of the problem (can't see that being the case) but might early feeding end up hindering progress rather than helping it?

Just a thought. Good luck anyhow.

Regards

Richard

Michael T Tue Mar 24, 2015 5:48 pm

Richard S wrote:I'm no expert so take this as more of an open question than a definitive statement but...............you say you are feeding this tree?

Is feeding a freshly root pruned tree which hasn't yet leafed out and is experiencing temps of around 60' F a good idea?

Depends really, I am presently keeping it in a sunroom where average temps are between 70f to 80f. I've put it out during the day time on days when temps have been in the 60f+-.

Most advice given is to NOT feed freshly root pruned trees until about four weeks after they leaf out.

The concern regarding fertilizer recently repotted trees typically involves the concern that some fertilizers at full strength can be caustic, i.e. burn the damaged roots, etc. I don't feed it full strength fertilizer. I have fed it with a heavily diluted fertilizer at about 1/5 or so normal strength. It's also planted in pure aggregate. The fertilizer that it has been fed is essentially washed out by the next watering.

In short, it's a very light feed. And typically I've found doing so tends to help recovery. That said, I'm not an advocate of feeding at full strength after root pruning either.

Not saying this is the cause of the problem (can't see that being the case) but might early feeding end up hindering progress rather than helping it?

Just a thought. Good luck anyhow.

Regards

Richard

Michael T Tue Mar 24, 2015 5:49 pm

Kevin,

I agree, I need all the voodoo I can get to avoid any bad mojo.

Michael T Tue Mar 24, 2015 6:11 pm

From bonsai4me.com.

Thought this was a useful summary of the concern..

"If the nitrogen content of the bonsai soil becomes too high it will burn the roots. Always follow the mixing and application rates described on the fertiliser packaging, never mix a higher concentration than is described and do not feed more frequently than is described. Overfeeding can result in less growth NOT more.
Trees that are dormant or sick should not be fed as they will not consume the same level of Nitrogen and salt levels in the soil can build up if care is not taken.
It is often recommended that newly repotted trees should not be fed for at least six weeks to avoid burning new roots.
However, there is now much anecdotal advice and some scientific evidence that promotes the advantages of feeding straight after root-pruning and repotting. Immediately after root pruning, a plant will require additional nutrients to grow and repair roots, particularly phosphorous and potassium. A low nitrogen feed would be very beneficial to the plant and unlikely to burn the roots."

Richard S Tue Mar 24, 2015 6:39 pm

Thanks Michael, that sounds reasonable (Bonsai4me is always worth consulting).

Good luck.

Regards

Richard

**JimLewis** Tue Mar 24, 2015 7:16 pm

I almost always fertilize after a repot and root work -- FWIW. The only thing I might disagree with in the Bonsai4me paragraph is the bit about burning roots. With bonsai that get watered frequently, I think you would have to pour the fertilizer at a 10-20X label strength to "burn" any roots -- new or old.

Richard S Tue Mar 24, 2015 8:35 pm

Well I've recently re-potted some of my trees so I might try giving them a weak feed as the leaves begin to open (the green is starting to show so shouldn't be long now).

Cheers

Richard

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