Poor growth and dead buds on potted blueberries

Asked May 31, 2014, 10:46 AM EDT

I've been growing blueberry bushes in containers for a few years and I've had a pretty low success rate due to something that kills the plants. I have attached photos of the current bush that is dying, I'm hoping you can identify what is causing this so I can treat the plant. The varieties I have are Duke, Northern Highbush-Jersey and Half-high-Northcountry. I have the plants in Roots Organic soil in containers outside. The plant seems to wilt starting from the tips and moving inward. The buds on this plant swelled and seemed normal but then wilted and died this spring. Small leaf shoots are trying to grow but then wilt and die. The branches seem to turn either lighter or darker brown and spotty. This happened in the middle of the season last year, killing the plant, and is happening to a replacement bush at the beginning of this season. One of the bushes that was close to the affected bush seems to have similar symptoms on the branches closest to the affected plant. Do you know what is causing this? And if so, how can I treat it? I haven't tested the pH of the soil, and I know they like lower pHs but I'm confused as to how pH would affect another plant close to the affected plant but not all of the plants I own, as they are all in the same brand of soil. Thank you very much for your time. Sincerely, Adam Girard Albany, NY

Albany County New York

5 Responses

I am wondering if it is fertilizer burn. When do you fertilize and how much. how big or the pots. Looks to me like something is wrong with the roots. How often do you water in the mid season and is it the large plants that wilt in the summer but the small one that collapse in the spring.

Thanks for your reply.

I have the plants in 5 gallon containers.

In the summer I water depending on how much rain falls but during dry stretches it is generally once a week.

In terms of fertilizer, I only fertilize when it doesn't rain and I usually mix up a gallon batch of water with 1 T of Jungle Juice Bloom and .5 T of Jungle Juice Micro, (ends up being a 5-5-5 mix) then lower to the pH of the mix to about 4-5 and water all plants evenly. This probably ends up being about 1-2 times per month in the summer.

In the winter I just leave them outside, close to the house and cover the containers with snow.

The plant that died mid-season last year was a Duke if I remember correctly and the current one is a half-high variety.

Thanks again for your help!

I usually recommend a rhododendron azalea mix like mir-acid because it has the right fertilize mix for acid loving plants. But it does not sound like fertilizer toxicity.The swollen but not opening fruit buds look a lot like what we have see here in Michigan as injury from the cold winter. Generally blueberries do not like to get below -10 and at -15 and colder we often see fruit buds that start to swell and then stop. We also see little leaves come out of the leaf buds and little new growth. The small black leaves and brown partially open flower buds look a lot like injury from a spring freeze. Our spring was late but we did get some cold damage from freezes. I doubt that happened in Albany but how cold did you get in the winter. Anything above the snow would have been exposed to extreme cold on a calm cold night. Duke plants do get a lot of diseases. But I do not have a lot of experience with half highs. The fact that the buds are dead but the wood looks good argues against a disease.

Thank you again for your help, it is very much appreciated.

I looked up the climate data for the winter and the coldest temperature was -12, so right within your range of -10 to -15.

In terms of any sort of spring freeze, we also had a late start. The last freeze was April 25. After that, it got down to 34 on May 7 but from what I've seen on your spring critical temperature page that shouldn't have been enough to damage the plant even at petal fall.

Is there anything I can do at this point to hopefully save the plant?

Thanks again.

The freeze would have been early at or just after bud burst. Your leaves look like ours did a month ago. Late growth in the spring is another sign of winter injury. I would watch the plant and once you get good growth prune off the bad parts. If the plant grows vigorously from the base I would cut it back and grow a new top.