1. @Walter Pall has revised his method of fertilization since this blog post was written. Last year he wrote this in response to a question I asked about fertilization
”I have changed d. Fertilization. learn about your tree species and requirements and fertililize accordingly. Some want a lot some much less. It depends. With some substtqtes you can over-fertilize. So be careful.”
2. Planting Gumpo Azaleas in So Cal in Cactus Jack…. I wouldn’t. Best to call to your local bonsai shop that works with lots of satsuki azaleas and see what they are using for their azaleas.
Highly doubt you will see these folks using 100% pumice… likely mostly Kanuma depending on the shop.… yet pumice is very useful as a component or alone for many other tree species.
btw the way the black gooey stuff your azaleas came in is likely mostly peat and perlite with some bark tossed in. Not a great media for bonsai azaleas. When you get ready to plant your azaleas in the media you select, wash off all…. Repeat all, of the old peaty mix before planting in the new media.
There is an extra large grade vermiculite….along with grade 3 perlite that is quite large……I love these substrates…..also been fascinated with Grodan grow wool….after all it is basalt stone fibre…….can interlace it strategically in smaller pots.
The large grade vermiculite can be in chunks up to 1/2” and is quite neat……The secret for me is watering with the black powder form humic acid and the white perlite changes to brown after a week of water.