Ask GreenTech-Pagoda Dogwood

Q:
“One of my clients called to tell me the Pagoda Dogwood planted last year have orange branches and some dead branches. They said they thought they watered them enough. What can we do?”

-Residential Landscape Designer

A:
It sounds like you have canker on your hands, a fungus that turns the stems bright yellow, possibly with orange spots. Pagoda Dogwood (Cornus alternifolia ) is a useful and beautiful native tree, but like most Dogwood, is prone to canker if stressed. Canker can spread through the plant, so you will want to remove and dispose of the infected branches. Prune well below the yellow tissue, down to the base or collar of the branch. Be sure to disinfect the pruners between cuts to avoid spreading the disease. A ten percent bleach solution is an effective and economical sterilant for tools.

The good news is, with a little observation to figure out what stressed the trees and caused the canker, you can make corrections to set the plant on a healthy path. You will have to look at the site, handling, and care. Pagoda dogwood is a forest understory tree, so consider the conditions in its natural habitat: cool, shady, moist, sheltered, forest soil. If it is planted in a dry, hot, sunny, or exposed site or in soil that is heavy clay, it will be stressed and more prone to disease.

Digging is also a stress, and Pagoda Dogwood are one of the species that are naturally slower to recover from transplanting. We have seen better success with planting container-grown Dogwood, because of the reduced transplant stress as well as the ability to better regulate water and amount light in the container ranges (More information on GO Trees-Container Trees). Adequate mulch and water until the tree is established will also reduce stress and improve success.

If the site is going to continually be a problem for the Dogwood, you may want to look at alternative native plants that are more adaptable to the site conditions. Native Viburnums (Blackhaw, Nannyberry, Arrowwood) can have similar form, flowers and fruit, but tolerate more sunny, dry, or clay sites.

See this factsheet from UW Extension for more information

-Mary T. McClelland- GreenTech

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