The Garden Community for Garden Lovers

Washington, United States Us

My Mahonia Oregon grape leaves' all turned red and stayed red for a year. It is starting to turn a little yellow now. The Oregon grape was planned 2 years ago and was beautiful. What’s wrong with it. Someone please tell me.

On plant Mahonia




mine has had some red leaves and I put it down to high temps and a lack of water. But there may be a better explanation. They have greened up this spring.

Welcome to GoY too :o)

27 Apr, 2020


They look chlorotic to me, Samparis. That is usually caused by alkaline or salty soil or water. A soil test may be in order, and sometimes the local Cooperative Extension can do that for you. Otherwise, there are many private labs that do soil and water tests.
If the soil pH is too high (>7.5), the solution is usually deeper, less frequent watering, switching out the rock mulch for an organic one, and/or applying soil sulfur pastilles--rather than the crystalline form.

27 Apr, 2020


Thank you for your comments. They are very helpful. Our soil is Ph 6.5 according to my tester.

28 Apr, 2020


Hmm...6.5 would be just about ideal for Oregon Grape. Maybe some rare mineral deficiency, like boron, or copper? Also, does your tester reach at least 6" underground? Have you ar a neighbor used a weed killer such as prometon or glyphosate nearby in the last two years? Adding a close-up of the newest leaves would tell us more.

28 Apr, 2020


that could explain mine then Tug as my soil in that area is pH 7.5 over bed rock chalk. As it is not far from a Camellia that I do give a feed designed for them [to prevent chlorosis] that would help the Mahonia stay green.

28 Apr, 2020


Severe lack of nitrogen could cause those symptoms, too. If it hasn't been fed recently, a handful or two of blood meal might help.

28 Apr, 2020

How do I say thanks?

Answer question

Related photos

  • Mahonia media Charity. (Mahonia x media (Lily of the valley bush) Charity)
  • Frosty Mahonia (Mahonia japonica)
  • Mahonia 'Charity' (Mahonia)
  • Mahonia 'Charity' (Mahonia)

Related products


Related questions

Not found an answer?