British Columbia: What's happening to these cedars?

Hello all,

Thank you for sharing your opinions and knowledge. I am new to these forums, but have found the threads extremely interesting and useful.

I am writing about the slow browning of some recently planted seven-foot Excelsa Western Red cedars. I have read several posts about this problem occurring with other cedars and the possible causes (e.g. lack of water; too much water/root mold; invasive insects; poor hole drainage; over-fertilization/nitrogen burn; etc.). However, I am not sure if any of these is the problem affecting my trees and I am hoping for some particularized responses from you experts. Please forgive me if my issue has already been addressed.

The backstory:
About a month ago, we planted approximately 30 seven-foot Excelsa Western Red cedars in our yard in West Vancouver. Because the planting area was on top of a very steep slope, it was difficult for us to move the trees without heavy machinery. We were advised that, while not ideal, it would be possible to open the burlap around the rootball, shake out much of the soil, transport the tree without the soil on the rootball, then plant in the hole by replacing the original soil around the roots to fill the hole.

First, we managed to plant four trees with the rootball intact; we planted those trees without removing the burlap, using potting soil to fill in the rest of the hole. All the other trees were planted without the burlap, with the original soil placed around the roots, supplemented with top soil.

We dug our holes deeper than the root ball and placed a thick layer of the original soil and bone meal at the bottom. The ground in the planting area is a mix of sand and clay, but there are other excelsa cedars growing naturally in this area, so with the addition of the trees' original soil, we don't think the ground is the problem.

After planting, we did not have an effective irrigation system in place (the soaker hose was not consistent in pressure because it had to travel up the steep slope), so we watered manually with the hose for the first week until we could get a drip-line set up. Now each tree has a 2 gallon/hr drip line that releases water through a mini soaker wrapped around the base of each tree (though we estimated that due to the lack of pressure caused by the slope, the water is releasing at a rate of approximately one gallon/hr). We are now watering regularly every night for about seven hours, but were concerned that the trees did not get enough water in the first week.

Almost immediately after planting, the first four trees (planted with rootball intact and wrapped with burlap) began turning brownish orange from the top down. Slowly, the same thing began happening to many of the other trees.

Now, about a month later, the first four trees are more than 50% brown/orange, and about half the others are more than 25% changed, whereas ten trees are green and unchanged. Many of the trees changing colour have fallen leaves around their bases.

Initially we noticed a yellow dust at the base of some of the trees. Two weeks after planting, we were advised to add more bone meal, but we couldn't find any in stores (all sold out!), so we used some Miracle Gro fertilizer for trees and shrubs 18-6-12 because it claimed to be organic and contained bone meal, feather meal, kelp, and earthworm castings (see product here: Fertilizer for Trees and Shrubs - 18-6-12 - 2.04 kg)

Since then we've learned that:
(1) despite the fact many tree-vendors suggest planting with the burlap on, this practice is in fact not good for the trees; and
(2) nitrogen and fertilizers are not necessary for cedars at this stage, and can in fact be damaging to the roots.

Current Concerns:
A month after planting, more than half the trees are turning brownish-orange, with the first four (planted with burlap) in the worst condition. About ten trees are green and unchanged (particularly those we planted last and which benefited from immediate application of the drip hose).

We concede that the trees may have lacked some water in the first week, but they have since been watered regularly (to make up for the initial lack) and the soil is now consistently moist at the base of the trees. We suspect that the first four trees are suffering because of the burlap, but that doesn't explain why the others are changing (as they were planted without burlap).

We are also concerned that it was erroneous to use the Miracle Gro and that the nitrogen content may have been damaging. But we used that product on all trees, and about 10 trees are green and unchanged.

I've included some pictures that show the different trees.

Our Questions:
Does anyone have any theories about what the problem(s) could be?
Is there any other curative action we should take?
Are the trees dying or is this normal?

Thank you in advance for your time, effort, and wisdom.

Sincerely.

 

IMO, lack of water in the crucial after-planting time was the problem. Disease moves slowly in trees, you wouldn't see root rot in a week or a month. These ones had already suffered the loss of a quantity of feeder roots getting cut off when they were dug up and burlapped, then lost more due to dehydration. Cedars are thirsty trees to begin with. Adding fertilizer on top of that was the equivalent of you drinking a glass of salt water when you are already dehydrated. It makes you much more thirsty! The ones getting consistent moisture were able to balance out the fertilizer by sucking up more water. Just keep doing what you are doing, water the heck out of them. If the sad ones haven't shown any new green in a couple of months, they are probably toast. They will make roots before greenery though, so don't give up on them too quickly.
And yes, removing all the wrappings is best. I've dug up a good few dead trees planted in their wraps, still with roots going around and around in a ball, twine and wire embedded in the trunks, sometimes they even strangle themselves in their own roots. Pretty sad.

 

Those poor trees! From their point of view, planted in a very unfortunate situation with a path on one side and a steep slope on the other, where are their roots supposed to grow? Even if they survive their first year, keeping them watered sufficiently will be a life-long challenge especially with the current trend toward less rainfall during the dry months. Here on Vancouver Island, dozens if not hundreds of Thuja plicata in the wild have died over the past few years, mainly due to a lack of water during the summer.

 

Hi Margot,

Thanks for your reply.

I know that cedars are having a hard time during the summer in this area due to lack of rainfall. However, despite the steep slope and path, there are many other cedars nearby growing well under the same conditions (both natural and planted), some younger like ours, but others are well-established.

- Do you think it is because of the location that they are starting to change colour?

Now that we've got the drip-line set up, water is less of concern for us -- for now. You are right that this will likely be a future problem if the summers continue to be increasingly dry. But we're hoping for the best!

 

Hi Heathen,

Your reply is very informative. Thank you!

We'll keep watering abundantly and keep an eye for new green growth.

- Do you think it is worth it to dig up the four trees planted in the burlap to remove it and re-plant?
- Or would this be too much of a shock for the trees?

 

Any that have gone brown will need to be replaced.

 

I'm not sure on that one. It would be a bit of a gamble. I think I'd dig a couple of small deep test holes next to the outside of the root ball and see where things are at. If roots are already coming through the wrap, probably best to leave it alone. Digging them up would wreck the new growth. If nothing is coming through, pulling it up would do less harm (and a greater chance that the tree was already a goner, so why not try).
This is just my theory though, I haven't dug up a live tree still in wraps, only the dead ones. And I like to experiment. That's my disclaimer. Perhaps someone else on here has tried this before. :)