Hope I found the appropriate area to post; (conifer area closed...) I have read everything I could find on this subject; but would still like some more opinions please. I bought many thuja occidentalis "nigra" for a hedge row, and planted them in April. I have a drip line (1 gallon per minute emitters) and have soaked them for several hours a couple of times a week. Through the summer (35 degrees) they did wonderful; did see some further expansion of previous growth filling in. (Are they now "established"? ) Of late they have started to turn brown (beginning of Sept.) I understand this is normal for a certain percentage of the foliage, but it is getting upwards of 20% of the tree? which I don't think is normal. It has rained quite alot this September, as most of us in the lower mainland area are aware of, and while I have now stopped watering the trees, I did leave the dripline on all day in late August.. I have called the grower and he is quessing they have too much water lately, and are starving for oxygen, but he is not able to see if the soil is bluish. The soil does not look blue to me. (?) The soil has always been damp when checked, on most trees, so I really don't think it is a lack of water, but I don't check them every day...I have noticed today plenty of roots seem to be cracking the surface (under the mulch) of the ground 10-20 cm from the trunk. Are the roots searching for oxygen? or are they looking for more water, as the mulch is wet? not sure... So I am wondering, do the pictures look like they are drying out? or flooded out? All the browning is the older growth on the inner branches; all the tips and tops are green. Would they look the same in each case? and should I let the soil completely dry? or keep watering them?
In the photos, the reddish foliage looks oddly sporadic. On the other hand, its more interior than exterior. Even on individual small twigs. If you overwatered, seems that discoloration would be more overall than distinctly separate from one part to the other. Is there any fine dust anywhere or small holes near the base of discolored twigs or foliage? How do you happen to keep track of how moist the root ball soil is? Or do you just water without checking under the surface?
Well, after a couple of Indian summer days of 25 degrees C, it has almost dried up; still moist a few inches deep, and the mulch is still moist... not sure what else I am looking for? I have cleared the mulch off the bottom of most of the trees to allow the soil to dry and get some more air in.
I see no dust or holes. A couple of webs near the bottom of at least one tree, but thick web so I think a regular spider. I dig a few inches with my finger before deciding to water or not (April - Aug). I have been careful not to dry out the root ball, but the grower says that would be okay now, and perhaps they not need any water at all until spring? One promising thing a closer inspection found was some new growth where the dead limbs are: seems new branches are replacing the older ones? I just don't know if this is an annual flagging event, or just a flooding issue, or a new tree getting used to its new surroundings situation.
