Eastern Hemlock Treatment

Asked February 17, 2020, 9:14 PM EST

I have a number of eastern hemlocks on my property. In early fall 2018 a tree service treated them with a systemic trunk application of Safari because they were struggling with an infestation of hemlock woolly adelgid. The trees were doing poorly even though in previous years they'd been consistently sprayed with a combination of horticultural oil and pyronyl. This year my hemlocks are fairly healthy, and the woolly adelgid is under control. My tree service is now recommending: 1. Pruning to remove dead limbs from the hemlocks to aid health by eliminating "attractive habitat for opportunistic insect and disease pests." 2. Using the phosphite product Fortiphite "to stimulate plant vitality" and to "switch on the hemlocks' defense system. Do you think that either or both #1 and #2 would help my hemlocks? Thank you.

Baltimore County Maryland

1 Response

It would not hurt to prune dead wood. Fortiphite is not needed.
Monitor the tree for the adelgid and treat if necessary. https://extension.umd.edu/hgic/topics/hemlock-woolly-adelgid-trees

Marian