Advice From the Help Desk of the
UC Master Gardener Program of Contra Costa County

MGCC Help Desk Client:  I've attached photos of our Patriot blueberry bush. Why are the leaves turning brown and curling? The problem began about a month ago. We tried to treat with acidifying powdered fertilizer, applied to the soil and cultivated in prior to watering. We water every other day or as needed (we check soil moisture with a short stick). The plant is now sending out new growth which looks relatively healthy.

MGCC Help Desk Response: Thank you for contacting the UC Master Gardener Program Help Desk with your blueberry question. You wrote that the leaves were turning brown and curling.

Your photographs were helpful. We think the plant has been experiencing sun scald and/or water stress. Several different factors may be contributing to this.

1. Blueberries have a shallow root system. During times of high moisture demand the roots may not be able to keep the leaves hydrated. This is especially true for container plants in full sun where during significant heat spells they will likely need water every day. To help the roots function, we recommend that you put an inch or two of mulch such as wood chips, or well-decomposed compost on the top of the soil (but keep it at least an inch away from the stems). This will help the soil to remain cool and reduce water loss.

2. Shallow rooted plants are susceptible to damage from cultivation. When you apply fertilizer or acidifier, just water it in without cultivating. Plants with damaged roots will have a much more difficult time absorbing sufficient water.

3. Shallow rooted plants need room to expand sideways in order to have an adequate root volume. We recommend that you re-pot your blueberry plant into a wider container in the fall once the weather cools down (e.g. November). Wait at least 4 weeks after re-potting before applying any fertilizer.

Additional information on growing blueberries can be found at this University of California website http://ucanr.edu/sites/gardenweb/files/29062.pdf.

I hope that this information is helpful.

UC Master Gardener Program of Contra Costa County (JL)

 Note: The  UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions.  Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA  94523. We can also be reached via telephone:  (925) 646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog  (//ucanr.edu/blogs/CCMGBlog/).