look very close ... could they be browning pollen sacs from spring???

i cant really tell from the pix ....

if a recent transplant.. rarely is drip irrigation sufficient for the deep watering thru the root zone ...

you might want to take a hand trowel ... dig a couple 3 to 6 inch holes.. and FIND OUT about moisture at depth ... if its bone dry.. and off color.. it may be death.. or near death ....

i dont get in the pic.. why what appears to be the back part is a different color.. whats going on there???... maybe a pic from the other side ... it might be a different plant????

if its not pollen sacks.. then its a watering issue ...

big city location always helps.. are you in drought???

ken

ps: on reviewing the pix.. i doubt my pollen theory ... see theory number two ...

https://duckduckgo.com/?q=conifer+thuja+pollen+sacks&t=ffnt&iar=images&iax=images&ia=images

Hello and thanks, Ken. For theory one, they are not browning pollen sacs. The tips of the branches are brown.

-- i don't get in the pic.. why what appears to be the back part is a different color.. whats going on there???... maybe a pic from the other side ... it might be a different plant???? --

Yes, it's a different plant. I included it in one of the photos to show the contrast between the two. The browning arbor vitae used to be a vibrant green color and larger than the other two.

-- if its not pollen sacks.. then its a watering issue --

I've been watering all three of them twice a week for 30-60 minutes with a drip hose for about 2 months. I've also given the sickly arbor vitae some Fox Farm Bushdoctor Boomerang Comeback Formula twice a week for the last month.

-- are you in drought??? --

Always. We are in the Sierras near Yosemite; summer is always extremely dry, and it has been very hot. This is why I've been giving them a good soaking twice a week. Do you think I should add a third day/week of watering?

Only you can determine ample watering by digging a few inches into the root ball to check moisture. Is there landscape fabric below the stone and if so how long has it been there? How are you keeping that area weed free?

tj

TJ:

-- Is there landscape fabric below the stone and if so how long has it been there? How are you keeping that area weed free? --

There is no landscape fabric below the stone. For the last 2 years, I have weeded by hand around the arbor vitae; farther out, we spray the stones while shielding the arbor vitae so no spray reaches them.

Thanks.

when i used drip irrigation.. and needed to get moisture at depth .. i had to run the system for about 6 hours.. ...

i said above:

you might want to take a hand trowel ... dig a couple 3 to 6 inch holes.. and FIND OUT about moisture at depth ... if its bone dry.. and off color.. it may be death.. or near death ..

Thanks, Ken, we'll give that a try.

I don't think it's bone dry though as the other two arbor vitae nearby are fine, plus the one in question was in the best condition until this season, with less watering than we are doing now.

Fingers crossed we can save the plant!