Why are the leaves on my blueberry plants falling off?
I have five blueberries that I planted last year and this year. The leaves are red/yellow and falling off. They have been like this since early summer. Any thoughts? Do I need to make the soil more acidic?
As you know, blueberries are deciduous plants (meaning they shed leaves for the winter), so reddening/dropping of leaves in and of itself is no cause for alarm. But it is a little early for that to be happening, which means the plants are probably experiencing some kind of stress. Unfortunately, there are a number of things that can cause stress-induced foliage reddening or loss. I do recommend that you get your soil tested through the UMaine Cooperative Extension Analytical Soil Laboratory–it is certainly possible that you do need to add some sort of amendment, but I definitely wouldn’t recommend acidifying the soil without knowing what your starting point is. It may also be that the wet season we’ve had has stressed the plant, if the drainage is less than ideal, or altered the pH and nutrient content of the soil. The soil report will give you an idea of what your pH is, what your levels of required nutrients are, and recommendations from the lab for adding anything to correct the balance.
I will also pass along a link to the UMaine Cooperative Extension Bulletin #2073, Growing Wild Blueberries at Home for information on management and best growing practices. I see that you are using cardboard to smother some of the nearby grass, which is good, as turf can sometimes compete with the blueberries. If these were planted in a cleared lawn space, you may well be looking at pH issues. Keep in mind that blueberries like plenty of sun and well-drained soil–you might consider raising them a bit in a mount or berm if they are flush with the grass and tending toward wet soil.