Trees, Shrubs and Conifers: Need tree ideas to correct my driveway monoculture, 1 by stressbaby

stressbaby wrote:
Hello. Bear with me while I post 3-4 pics. There is a question at the end...

We bought our house 9 years ago. At that time, the drive was lined with some 25 15-20' tall Colorado Blue Spruce. I should have seen it coming, because already when we moved in, two of the trees had been sawed off at the base and removed. Well, to make a long story short, after staking, spraying, fertilizing, horticultural consultations, samples to the extension office, etc, these 25 trees were pruned with a backhoe due to some combination of decline and disease.

Wanting to preserve the "allee" look to the drive, and failing to hear or heed any warnings against monoculture, I replaced all of these trees with Ulmus parvifolia. Yeah, I know...but I was following the advice of dear Dr. Dirr who fell all over himself in the 5th edition of the Manual praising this tree.

Well, to quote Lee Corso, "Not so fast, my friend." I have found only a handful of seedlings. But I have lost about 6 trees to some type of borer. Further, the tree is occasionally prone to producing bark-trapping narrow branch angles. Don't get me wrong, most of the trees are beautiful, and quick-growing. Most of the trees planted at 3' are now 15-20' tall. But I replaced three this winter and two more are gone or going.

Here is a pic.