white powder like substance on cedar hedge trunks
it seems to be a kind of fungus it started when we put wood bark mulch under the hedge what do we do Mike
Outside United States
A photo would be extremely helpful in answering your question. However, is the mulch actually touching the tree bark? If so, you need to pull it away by several inches to prevent moisture from accumulating on the trunk. Otherwise, you will have an environment that encourages fungus.
Keep in mind that the purpose of using mulch is to maintain moisture in the soil. The tree roots grow away from the trunk, so that is where the mulch should be: over the soil surface out to the drip zone of the foliage.
If this does not answer your question, please send a photo of the tree trunk and fungus and we can try to advise you further.