My arborist just planted a river birch that looks pretty dead to me. The leaves are shriveled and the rootball is pretty compacted and dry from about 2 inches down from the top. He said just to water it and it’ll come along fine. How can you tell for sure that a tree is dead?
The Gardener’s Answer
Hello, Netha in California: Hopefully this arborist of yours is a certified one. There are a lot of self-proclaimed arborists out there but certified arborists are the real deal and take their profession seriously. They have to continuously take classes to stay up to date on their certification. As far as knowing if your river birch (Betula Nigra) is still alive is to scratch the bark to get to the cambium layer, which will be green if the tree is still alive. If you purchased this tree at a nursery you may want to check and see what their guarantee policy is or if your arborist has a guarantee or offers a replacement in case of loss. River birches are quite adaptable trees but are happiest growing in full sun to part shade. They are pretty disease-resistant and tolerate a range of soil conditions. At this time of year your tree is going to be losing its foliage and going dormant so you will not need to water as much as you would in the heat of the summer, but newly planted trees will still require a good soaking after they are installed. A thin layer of mulch will help retain moisture and heat, protecting the roots. At this point, if the cambium is still green, it will be a waiting game to see how it does this winter and hopefully it puts on new growth next spring. Do not fertilize this time of the year since this encourages growth that would be susceptible to winter injury. Hopefully the tree is healthy, planted properly, and you can enjoy it for years to come.