Banksia shoots dying

[Boics]

I'm surprised that only Mike suggested P toxicity because that's usually the first thing blamed for any banksia problem but I assume that's because many of you are aware of my thoughts on banksias and P so hesitated to jump into that trap.

That's because I just assumed you knew how to water....

SNAP!

[Rory]

Well I guess we’re at fault for not asking when it was last repotted.
I too assumed like Mike that watering wouldn’t be an issue, but I guess it’s a timely reminder to not assume anything.
I would also assume if this question was being posed by a newbie that the answers would have been very different.

[shibui]

That's because I just assumed you knew how to water....

Absolutely Mike Did I not make the point that when trees get to this stage it doesn't matter how well you water? If there's no spaces in the mix water just cannot get in.
The banksias I've grown here all seem to have this massive root growth. Far more and far quicker than I thought possible. I assume it will be the same in other areas for other growers.

Initially I put banksia deaths down to them being temperamental or to P toxicity and a few other factors and I'm pretty sure that others have had similar experiences and banksias now have a bad reputation because of it. Now that we are aware this happens I'm hoping this information will help give others a better chance to grow some great banksia bonsai.

[treeman]

That's because I just assumed you knew how to water....

Absolutely Mike Did I not make the point that when trees get to this stage it doesn't matter how well you water? If there's no spaces in the mix water just cannot get in.
The banksias I've grown here all seem to have this massive root growth. Far more and far quicker than I thought possible. I assume it will be the same in other areas for other growers.

Initially I put banksia deaths down to them being temperamental or to P toxicity and a few other factors and I'm pretty sure that others have had similar experiences and banksias now have a bad reputation because of it. Now that we are aware this happens I'm hoping this information will help give others a better chance to grow some great banksia bonsai.

Because you say this.......

Despite a good soaking last night and again this morning the centre is still dry

....it tells me that the problem is hydrophobia. Oil and waxes secreted by certain fungi (I think) coating the particles make it impossible to rewet using standard watering practices. The only way around it is repotting or using a wetting agent. It's not that water cannot penetrate because of root binding. Water is able to penetrate the finest of pores but obviously at a slower rate of infiltration. So this problem will come about if water is removed by roots and evaporation and is not thoroughly replaced. If you have a problem with shoots wilting earlier than they generally should, you may have this developing in the pot. Submerging in water containing a good wetting agent like ''Wetta Soil'' will fix the issue for the rest of the season. Also, be aware that there are many cheap wetting agents out there which are completely useless, including the so-called natural ones.