Browning Hemlock

[Kenzen]

Am getting ready to see a friend's hemlock I treated several years ago (5) for HWA and now he wants me to look at the tree due to it turning brown in the interior but with new growth on the ends. Could be anything from natural needle loss to Phytophthora since they have had issues with drainage on some other plants. So anything else I need to look at? I will take some pics if I am unable to diagnosis the issue. I usually do not have to treat any hemlocks beside for HWA.

 

[Raintree]

Not much info to go on here. Look for...
Properly planted
Shady site or full sun
Poor drainage = low oxygen
Soil fertility
Scale
Size of new growth
Color of last years needles

I would guess normal needle loss.

 

[ATH]

You treated it once 5 years ago? Has it been treated since?

 

[Kenzen]

Yes five years ago. Have not seen the tree in a while, but I believe needle loss. Still they have planted trees to close to concrete driveways, overcrowd plants, have some drainage issues, and all of that will be looked at. I did show them what to look for for HWA. And have had luck with imidacloprid lasting up to 7 years in healthy trees so will look at treating them again. I will get back with you later

 

[Raintree]

Unlikely interior browning is due to a biotic issue.

 

[Kenzen]

He did contact me after asking him to get a better idea and said that their are healthy needles on the interior then brown needles then healthy new needles. So I'll have to look at it no matter what his description is, take some samples and take home to look at under hand lens.