Help wanted..sick Banksia

[bodhidharma]

To Pup and all the Aussie Native specialists. This Banksia was blown of the bench in a gale and totally dislodged out of the Bonsai pot it was in. The top was snapped of and two main roots were damaged. I immediately repotted it into a large pot and put it under cover. I slowly added a little bit of organic fertilizer, which is quite complete. It has trace elements, seaweed, fish emulsion etc. N.P.K. is 4.3.2. I thought i had saved it but it has started doing this(see pictures).Gentlemen, could i please get some advice and can it be saved. The tree is, maybe, 10-15 years old. It is still pushing new growth but it is also yellow.

[Pup]

Bohdi I do notice some Green there so at this point may be just may be.
I would reduce the it down to the first branch, and tilt it so you have some thing to start rebuilding with and reduce the amount of work it has to do to repair its self. I would just use seasol at this point until you see a positive response.
Remember this is what I would do. There may be other's with more experiance with Banksia's than I that have some Idea's also.

Good luck Bohdi, Cheer's Pup

[bonsaibruce]

I have had this happen to one of mine. I cut off everything that was not green, and any brown or yellow bits on any leaf. Cut off any growing tip to a green leaf.
Good Luck.
BB

[kcpoole]

How weird, Never seen one do that before
If it is pushing ne growth, then I woud remove any bits that are yellow and let it recover before doing anyhing else

Ken

[Jarrod]

That's nice autumn colour...

I would as do said above. Got my fingers crossed, I love a good banksia.

[MelaQuin]

Above advice is good. I think you should have removed most of the foliage at the time you discovered the tree. Anytime there is a lot of root damage/dry out the foliage has to be reduced. Next suggestion - if it were my tree I would put it in a water tray. Banksias like a lot of water and if the tree is struggling this could help. If you don't want to do that then I would be watering it two to three times a day. But a water tray is easier.

A friend removed a fine top show quality cascade banskia from the pot to repot it and left most of the roots in the pot. She was sickened by the accident but repotted the tree and the damn thing never turned a leaf... it had a large quantity of foliage and maintained the lot. I don't know how... but the tree was shaggy as hell the last time I saw, ready for a heavy prune, it and she was smiling broadly. Maybe the same genie take a shine to your banksia.

[Grant Bowie]

Banksias can suffer root rot and a damaged tree with damaged roots and too much water may cause root rot.(Not enough healthy leaves now to suck the water)

I would consider a dose of Fongarid in case there is root rot that is causing the leaf yellowing. I think the advice about cutting it back hard at the time of the accident was correct; both top and roots with sharp scissors but it may be too late now to take that course with the state of the tree now.

It looks like a Marginata? Correct?

You stand a good chance because of where you live. They like your climate.

Good luck.

[Joel]

Here's my theory.....

It fell out of the pot, dried out somewhat, and became stressed. This caused the banksia to put out proteoid roots. These roots are capable of picking up lots of water, but most importantly, lots of nutrients..... particularly phosphorus. The fish emulsion had 3 for the phosphorus, which is above the maximum recommended "2". Whilst i have used far higher than 3 without problems, i only do it when the tree is in good health and is not root bound or stressed. The high phosphorus means plants in proteaceae family (like banksia) have great difficulty absorbing and using iron. Whilst iron chelate might help the problem and cause the leaves to green up somewhat, the phosphorus poisoning will remain for a while. Phosphorus takes 50 years to leave soil.

As for what to do? I recommend the above advice, but i would consider applying some iron chelate at HALF strength, to see how it responds.

Good luck!

JayC

[bodhidharma]

The knowledge being shared is wonderful. Thank you Bonsai people, i have made the moves suggested and now we wait.

[Edward Scissorhand]

Good advice JayC. Put in some iron chelates, it will work temporarily and the leaves will turn a green instead of yellow. But the green wont be dark enough so If possible change your soil mix next year with aussie native soil mixed with some sand and course mixture. Then fertilise with a native fertliser, something with very little to no phosphorus. This should improve the chlorosis problem. Also Grants advice on root rot is important. Banksias are well known to be succeptible to phytophthora, get some fongarid and put it on as a preventative. Was there any die back? Anyway Good luck.