I am pretty sure it is not a virus because all hundreds of plants showed this symptoms at the same time. 3 days ago I selected few plants and applied Phosphorus acid on some, Magnesium sulfate on others and I sprayed some with micro elements and high nitrogen content foliar fertilizer. We'll see what will happen. I think it might be something with the weather. The last 20 days the temp. during the day are like 25-28C (80-83F) but during night temp is dropping to 6-8C (43-46F). That's why I thought it might be phosphorus that is deficient.

Well, Carol definitely put me on the right track. There evidently are A LOT of Callistemon species and varieties out there. Probably what I saw was Callistemon viminalis or linearis - possibly some variety of rigidus. There is a website out there (link below) 'Australian Native Plants Society' that has some marvelous info on this shrub/tree. Thanks again, Carol! Ginger Here is a link that might be useful: Australian Native Plants Society

Sounds like an Oxalis of some sort.

I think your plants may not have been acclimated that much direct sun. It could be a disease, but looks like sunburn to me. I've had one of these in a pot for a few years and every time sun shines directly on it except the very first or last rays of the day, it burns. I gave up trying to acclimate it to any direct sun since it looks fantastic in all shade, very red leaves with an occasional pink stripe, made flowers about a month ago inside the house.