I am a professional landscaper in the Portland area. I am wondering if Betula jacquemontii have much of a problem with aphids or other pests. Everything I read says they do, but since this tree is one of the Great Plant Picks, I wonder if that’s not the case.
There is certainly the potential for aphids with this type of birch. I don’t think all the plants listed in Great Plant Picks are necessarily immune to problems, more that they can serve a particular purpose in the landscape. Betula utilis var. jacquemontii is also susceptible to bronze birch borer, according to Oregon State University.
University of British Columbia Botanical Garden Forums includes a discussion of the merits (or not) of this tree, including this comment from Seattle-area gardening expert Ron Brightman:
“Silver birch is customarily Betula pendula. It grows large and is an aphid magnet in my area. Betula utilis jacquemontii does not produce the same elegant weeping habit. But the clone commonly sold here displays stark white bark. Mine became infested with what looked to be the same leaf miner that can be quite abundant on native stands of B. papyrifera north of here. Finding the effects of the miners tiresome and this not being a rare tree here, I cut it down. Since native paper birch trees are abundant around Vancouver I would wonder if you might end up with the same problem.”
Here’s another link of interest, from Washington State University. It mentions that “this tree is susceptible to bronze birch borer, a wood boring beetle that will girdle the trunk. Aphids can be problem on the foliage. Excrement from aphid feeding can leave the ground sticky beneath this tree.”
Jacquemontii birch is common as a street tree in Seattle, and as the neighbor of a row of three of these birches, I can say that so far they appear relatively pest-free (I’ve seen a hint or two of sticky aphid honeydew on the leaves ), but they make voluminous leaf and bark litter which blows into my garden. I keep thinking the bark is wastepaper (grocery receipts, etc.). It looks great on the trees, but is a minor nuisance when blown far and wide.