ceanothus thyrsiflorus dying overnight

Asked August 23, 2019, 9:26 AM EDT

Ive had a thriving ceanothus thyrsiflorus for about three years now. Almost overnight it turned brown (see first two photos). I can't think of why this could happen or what I can do. It's been a mild summer. We put cedar wood chips on the whole south landscape a couple weeks ago but none of the other plants reacted to that and there's no reason this shrub should have either-- well established and was extremely healthy. Can you please help with anything I can try to salvagey shrub before it's 100% dead? Thank you! I have another native plant on the NE side of the house that also turned half brown about a month ago for no reason. Its counterparts are still thriving. This is a ribes lobii and I've included it in the third photo.

Multnomah County Oregon

1 Response

Thank you for using Ask an Expert for help with your shrubs. From the photos you included, it appears that these plants died while others around them are unaffected.

Generally, when a plant fails so rapidly, I would look to the root system or the lower trunk. This could mean a mole or other critter so damaged the roots that the plant could no longer take up water. Some rodent or squirrel could have scraped/damaged/remove enough of the lower bark that the upper parts of the plant could not get water from the root system. Check around this part of the plant to discover any damage.

I agree that the applied mulch probably doesn’t play into this (as other plants were unaffected). Unless it provided cover for critters to do damage to the shrubs, unseen.

Scrape the bark of the affected limbs lightly, with a fingernail. If the wood beneath the surface is green, the plant may recover, given adequate water. If the underlying wood is brown, there is little hope for recovery.

For an eyes-on diagnosis, you could bring a branch or two to the Multnomah County Master Gardener Clinic at Montgomery Park (2701 NW Vaughn St. Suite 450). And for more information, you can call them at 503-445-4608 (Monday through Friday-- 10:00 am to 2:00 pm).