Hi there, Wondering if anyone could offer some advise for my repeatedly dying cedar tree. The hedge is almost 7 years old and has about 65 smaragd cedars (7 ft now). The first year we lost 4 trees, which I expected may happen. I replaced all 4 but 1 of them continues to die every year. The same tree has been replaced 6 times now and my most recent is showing signs of iminent death. I'm not sure what to try this time. In the past I've always replaced in either fall or spring. I've used transplant fertilizer, dug a very deep hole and filled with new rich soil. I have been fairly good about watering during summer. The last one was planted in April & it was so wet and cool all spring I thought it may have a good chance. Any ideas would be welcomed before I plant lucky #7. Thanks Stell
'Smaragd' is an arborvitae (Thuja occidentalis), not a cedar (Cedrus). You'd need to check for soil drainage problems, or the possibility of soil toxins (e.g. if someone had dumped waste motor oil there in the past).
Cultivars and species differ in susceptibility to Phytophthora root rot. Western red cedar Thuja plicata is most resistant, T. occidentalis 'Pyramidalis' is intermediate, and T. occidentalis 'Smaragd' is most susceptible http://plant-disease.ippc.orst.edu/ShowDisease.aspx?RecordID=68
If it was Phytophthora, I'd expect the disease to spread to adjacent specimens, which it evidently hasn't.
Individual or scattered dead 'Smaragd' in hedges of various ages is commonly seen here and frequently asked about on the internet. If you look you are liable to find other discussions. Meanwhile, discontinue use of transplant fertilizer and back-filling planting holes with different ("rich") soil. Neither is beneficial, and the latter is often detrimental. You want the same soil throughout the entire potential rooting area, no pockets or strips of one material surrounded by another.
