Q.Japanese Cedar Issues
Hello there! I have two issues – both with Japanese Cedar – I’m hoping you can help with. I live in 7a (Long Island, NY) Issue 1 – Massive dead zone on mature Japanese Cedar – Recently noticed this huge area of dead growth in the plant’s mid-section. Top of tree is still green, as is the other side of the tree. Has been healthy for up until now. – Dead growth has grey/green spots. Mold? – Tree receives regular water through drip irrigation – Images at https://imgur.com/a/4iDUtwm Issue 2 – Newly planted Japanese Cedar going yellow & showing dead spots – Planted five 2′ plants in early September. Most seem to be doing fine, but one is overall more yellow than the others and showing dead areas. No grey/green spots like in the 1st issue. – No drip irrigation, just gets some water through the regular sprinkler heads (and it’s been pretty wet season generally) – Images at https://imgur.com/a/yOtYQqs
Certified GKH Gardening Expert
They need moist, acidic, well-drained soil. I would have the soil tested for its pH. If it's alkaline, that could be causing yellowing.
Also, too much water could be causing root rot, which is evidenced by browning in the center of the tree.
These articles should help: