Arborvitae thinning out soon after planting, and getting worse - Ask Extension
Hi, I am in Westchester County NY. I planted a row of tall green emeralds the last weekend of September last year. I watered quite a bit the first wee...
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Arborvitae thinning out soon after planting, and getting worse #638216
Asked May 19, 2020, 11:30 PM EDT
Hi, I am in Westchester County NY. I planted a row of tall green emeralds the last weekend of September last year. I watered quite a bit the first week after planting, at the roots only, and noticed browning starting to happen then. I stopped watering for the season and also had a drip line installed for the future.
Fast forward to May, 8 months later. They survived the winter, but thinned out even more. My landscaper and the nursery is claiming that this is from water damage from my sprinkler hitting it. I find the claim dubious because the sprinkler was barely hitting them, and some not at all, and even those became brown. They say they took them to 3 other nurseries that all said the same thing, and the nursery won't replace them.
A few other observations - the insides of almost all the trees is also quite brown, but from what I understand this is normal? I also do see new growth shoots out of the trunks, so I suppose that is a good sign.
So what does this look like? IS it exterior water damage from the sprinkler? Damage from my overwatering? Or something else?
Finally, for moving forward, the land scaper offered to turn some of them, where the backs aren't as bad as the front. Is this a good idea to do? We're also going to fertilize the trees. Any suggestions of what to use?
Thanks!
Fast forward to May, 8 months later. They survived the winter, but thinned out even more. My landscaper and the nursery is claiming that this is from water damage from my sprinkler hitting it. I find the claim dubious because the sprinkler was barely hitting them, and some not at all, and even those became brown. They say they took them to 3 other nurseries that all said the same thing, and the nursery won't replace them.
A few other observations - the insides of almost all the trees is also quite brown, but from what I understand this is normal? I also do see new growth shoots out of the trunks, so I suppose that is a good sign.
So what does this look like? IS it exterior water damage from the sprinkler? Damage from my overwatering? Or something else?
Finally, for moving forward, the land scaper offered to turn some of them, where the backs aren't as bad as the front. Is this a good idea to do? We're also going to fertilize the trees. Any suggestions of what to use?
Thanks!
Westchester County New York
Expert Response
It is very difficult to diagnose something just from a picture. I guess it is possible for the water to have encouraged a fungal infection and that could turn the leaves brown. You would need to submit plant samples to a diagnostic lab for confirmation. One can't tell by just a picture. You also could have been under or over watering. Most likely some of the root system was damaged when planting and it just couldn't sustain the whole plant and a few branches died. The soil looks compacted to me. It should be loose and fluffy and covered with a bark mulch to keep weeds down and maintain moisture. The inside branches always turn brown and even tho it is an evergreen, it still loses its needles, just holds on to them longer than a deciduous tree. I would prune out the dead branches and fertilize the tree using a 5-10-10 or an organic fertilizer for trees and shrubs. Better yet, have a soil test done (www.soiltest.uconn.edu). Arborvitaes are pretty tough and as long as the bottom of the trees get some sunlight, they should regenerate some branches - it just might take a year or two.
