Troubleshooting blueberries

Asked April 10, 2018, 11:00 PM EDT

Hi! I have two blueberry bushes, each with a different problem. One bush has tons of flowers but almost no leaves. The leaves I do see look healthy, though they are extremely sparse. The other bush also has lots of flowers and is quite bushy, but the leaves are a dark purple, some with brown spots around the edges. I recently applied sulfur (probably 3 weeks ago) and an all-purpose slow-release fertilizer. I'm happy that the fruit outlook is looking good for my two bushes, but it worries me that the leaves aren't looking great. Thanks for your help!

Multnomah County Oregon blueberry diseases small fruits

7 Responses

Blueberries may be affected by various diseases, some of them quite troublesome for home gardeners. At this time of year, it may be that only the old leaves are affected. If so, the remedy would be to remove them, then discard in the trash.

If new laves are affected, it’s probably too late to spray because sprays work only if applied before new infections begin to develop.

We need to have a clear diagnosis before recommendations are suggested, a process which relies on clear images of the problem.

Please send 3 images of both shrubs. Because you can only attach 3 images to one reply, you will need to reply to this email twice, once for each bush. The preferred images are 1.) the bush and its surroundings; 2.) the bush, itself; and 3.) a branch with both healthy and affected leaves.

Other details which may be helpful:

- The name of each blueberry shrub.

- When did the problem begin?

- What have you done so far? And what was the result – helpful or not?

This publication may also provide some useful information: "Growing Blueberries in Your Home Garden" (https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/ec1304.pdf)






Hi Jean, 3 photos of each blueberry attached. Not sure what variety they are. The only thing I've done so far this year is apply some sulfur, which was recommended to me by someone at a local nursery. Thanks!

Additionally, I began to notice these issues in early March. And the sulfur doesn't seem to have improved much. Thanks!

It’s true that sulfur decreases soil pH, but it takes an extended period to do so, about 6 months. So, it’s unlikely to see any response this soon after applying it.

In order to carry our problem-solving for your blueberries further, please answer the following questions:

1. How long ago did you plant the blueberries?

2. Were they bareroot plants or in pots?

3. (a.) Was the soil pH tested before planting? (b.) If yes, did you use a home kit or send a sample to a professional laboratory? (c.) What was the pH?

4. What kind of fertilizer do you use for the blueberries?

5. How do you water? (Hand-held hose; sprinkler; or drip system?)

6. How often do you water?

7. How many hours of sunlight do the blueberries get?

I look forward to receiving your responses.






Hi Jean! 1. How long ago did you plant the blueberries? 1 year 2. Were they bareroot plants or in pots? Pots 3. (a.) Was the soil pH tested before planting? (b.) If yes, did you use a home kit or send a sample to a professional laboratory? (c.) What was the pH? No 4. What kind of fertilizer do you use for the blueberries? All purpose fertilizer, EB Stone. I also planted them with a ton of new compost. 5. How do you water? (Hand-held hose; sprinkler; or drip system?) Hand-held in the summer, as needed any other time during the year. 6. How often do you water? This past summer, probably 2-3 times/week as it was so hot. 7. How many hours of sunlight do the blueberries get? 8 - 10 hours Thank you!

Thank you for the extra details.

The key, here, is that these are young plants and are most likely struggling a bit because of a somewhat high pH. Even so, we should be able to give them a good push toward the vigorous shrubs you need. Please review the info in “Growing Blueberries in Your Home Garden” as it has many of the answers you need. (https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/ec1304.pdf)

I didn’t think to ask when you planted the berries. Since they were in pots, perhaps it was summer or fall? If so, they barely have the beginnings of a sturdy root system. So, that needs to be your focus.

As soon as possible, remove all the flowers. (I realize that’s not what you want to do, but we have to change the plant from a reproductive mode to one that produces leaves and roots.) It’s critical that the shrubs develop a sturdy root system. If the plants are still a bit straggly next spring, again remove all the blossoms.

Blueberries need soil which is more acid that the natural range. The added “ton of new compost” most likely made the soil even less acid. To a certain degree, you’ll need to play catch up with adjusting the pH downward. The recent addition of sulfur was a good beginning. Changing the fertilizer to ammonium sulfate will help as it will continually do a small, but critical, part in lowering the pH. Fertilizer must be present when the shrubs begin to leaf out, then repeated several more times during the growing season, as described on page 4 of the above publication.).

Also add mulch, 2 to 3 inches deep, under the shrubs and extend it outward past the ends of the branches. A good choice is Douglas‑fir sawdust or bark, as noted on page 4.

Make certain the soil never goes dry. Your goal is evenly moist – the mulch will help with that. Never allow the soil to be soggy or dry. (Again, see page 4.) I see many stones on the surface of the soil. If that’s the general condition of the ground, the roots may be drying out more rapidly than you suspect.

If you have further questions, please ask.






Thank you, Jean! I'll work on following through on your advice.