Give it another few weeks. Try a scratch test on several twigs/small branches of the questionable ones. If the cambium is still green, then it's more hopeful. Make sure they have water, but don't drown them - and don't feed them either. If the cambium is brown, go further down the trunks/branches until you hit green. You can trim off the truly dead stuff, but be careful not to damage any possibly live stuff - it may be better to wait and be sure it's dead before you cut anything. Cut off the dead trunks at or just below ground level. The tree/clump should have a good root system by now, so if the trunks all are alive, they should go well, once they get going. If the two are dead, and you really want a multiple-trunked specimen, then you can select 2 or more strong suckers from very low on the base of the live one, and let them grow over the summer. Next year, you can select the strongest one(s), and go from there. It will take longer, but you will have a multi-trunked tree.

I am located in Northeastern OK. we are considered to be on the boundry between USDA zones 6b and 7. The first two years these originally planted bareroot 6 foot tall trees experienced severe droughts. The trees are planted in water packed silty loam soil in a low spot on my vacant lot. The water table is pretty high in that area and rain runoff collects on the surface in that area when we have heavy and/or soaking rains. Other than that, I have no piped in or well water access on the lot, so they have had to survive on whatever rains fell. As you can imagine they really stuggled. Earlier this year, they leafed out nicely and seemed to be turning the corner, until the Easter freeze hit; after they had already leafed out. They were not strong enough to handle the hit, and each of their single trunks died back significantly. The trunks were only about two inches thick at the time. Since the green just under the bark was only about 3 feet up after the freeze damage, I cut the trunks of the two worst damaged ones down to just above the root flare. The one in between those two seemed stronger so I only cut it back to about two feet above the ground. Later that middle one's trunk died, but a new trunk grew up out of the tree's rootball. Now my single trunked Birch tree is about 4 feet tall, and I have not pruned away any of the leaf growth to leg it up. For the two other birches, the ones I had cut back to just above the root flare. They turned into clumps and each regrew three healthy and strong growing trunks. Currently those trunks have grown to about 3 feet tall, and both trees look more like a shrub than a tree, since I have not done any leg clean pruning of the leaves on them either. All spring and even now into summer our area has received heavy and frequent rains; along with many overcast sky days. Our area is just south of the tragic flooding events that recently occured in Northern OK and Southern KS. We are also quite a ways north of the tragic flooding which has recently occured in central and southern OK and northern Texas. The point I am trying to make, is that these birch trees for the first time since they have been planted have not been stressed by drought, but they have been growing in 2- 4 inch deep standing water for extended periods this Spring and Summer. Due to the wet year we are having, I expect the trees to grow to at least 6 feet tall again, before they go dormant when I plan to transplant the two. My question? Is it reasonable for me to think I can move these two trees into pots and not kill the remaining one. I want to over winter the ones I transplant to pots that I plan to bury in the ground. Then just prior to them breaking dormancy in the spring I want to replant them into their landscape spots which will have supplimental watering access. As for my original post's intended question: since birch trees have more of a surface growing root pattern, will there be any purpose to root prune the two I want to move? If so, when would be the best time to do that?

It is usually the same reason for the yellowing. They are river birches so they are used to living alongside rivers. Any other place and they will have some leaf loss during the hottest of summer days. This will not hurt the tree, but is actually the way the tree deals with water issues. I heard in the urban landscape they can last only maybe 25-40 years, but that is not always the case. Good Luck!

LOL!! Brandon, I read that statement with exactly the same thought: "Gro low sumac is the most popular choice." ......sez who?? And why would one necessarily want the same approach as everyone else? There are literally hundreds of low growing, ground hugging choices for this situation if one wanted to cover the ground but it is not a requirement for river birch or any other tree. Mulch works perfectly fine if root protection is your intent. And any perennial that needs periodic lifting and dividing is not a good choice for underplanting larger trees. The root disruption is potentially quite damaging to the trees and the longer one waits before any necessary dividing, the harder it is to accomplish and with a higher degree of disruption.