I am trying to help my neighbors select trees for their front garden. The trees will be in a parking strip that doesn’t have any structures near it or any overhead lines and it is on the north side of a fairly large 2-story house. We live in an old neighborhood with very large, grand trees. One tree I thought might be a contender, which is approved by the city (Portland, OR), is Cladastris kentukea. My only concern is that the seed pods might be messy. The neighbors themselves were thinking of aspen (nostalgic for them, as Coloradoans), but I didn’t think this was a good idea. What do you think?
I checked in a few places, and the main thing that might be disappointing is that in the Pacific Northwest, Cladrastis kentukea doesn’t flower reliably (although that solves the small trouble of seedpods, I guess!). Local tree expert Arthur Lee Jacobson says the following, in his book Trees of Seattle (2006):
“In nature this is an uncommon, even endangered species. It has been recorded to 87′ x 23′ x 96′ wide, and has reliable bright yellow or even yellow-orange fall color. Its heartwood is also deep yellow. Uncommon in Seattle, Yellowwoods are unreliable as flowering trees: their white flowers appear full force in some Junes, but are absent or weak in most years. They have no other faults except a branching habit prone to breaking up; careful pruning can help with this.”
(The Seattle-dwelling specimens of this tree which Jacobson lists are between 23-60 feet tall by 4 to 8 feet wide)
Below are links to information and images, from Oregon State University. This tree looks glorious when it flowers! Provided the spot is well-drained, and has no history of verticillium, to which Cladrastis is susceptible (see the link from SelecTree below for details), it seems like a great choice.
As an argument against aspen (Populus species, usually P. tremuloides in our area), Arthur Lee Jacobson mentions that they tend to sucker from the roots. The SelecTree site mentions twig and dry fruit litter, high allergen count, and numerous pest and disease problems.