Winter and spring weather effects on Pittsburgh’s Street Trees

You may have passed by Tree Pittsburgh’s office recently and saw the poor condition of our street tree. The tree is a Persian parrotia (Parrotia persica) and is being tested at about a dozen sites throughout Pittsburgh as a future street tree. Many other cities have added this tree to their lists, but without a single older specimen in Pittsburgh to evaluate, we started planting just a few. A few have grown very well, but the majority suffer from ‘bud blasts’ for the first few years. These ‘bud blasts’ are where most of the buds are killed off during winter by cold, salt, or some other factors. Some of the trees have shown a strong recovery in the third year after planting.

While many other species are enjoying the heavy spring rains, some species are not as happy. Bald cypress needs warm sunny weather to really start growing. They got off to an early start with a few warm days in April, but haven’t really grown much since then. Newly planted London plane trees also seem to be suffering.

This winter had a big impact on flowering cherries and Japanese Zelkova. The majority of newly planted dead street trees seem to be these two species. Many of the cherries had flower buds that began to open this spring before declining quickly as if they had been hit by a hard frost, even though we had no frost.

We will and encourage you to continue to monitor these trees and keep them healthy by weeding and mulching throughout the summer.