Hi there. Ive grown blueberries for around 4 years with some success. You need to get some soil sulfur at acidify the soil. The pine needles make a decent mulch but dont provide any acidity to your soil. A soil test would be very beneficial as well. Are your leaves lush greeen? I would take alot based on the health of your bushes. I wouldnt be against using aluminum sulfate either,just use it in small doses.

Thanks Brandon. Can I find the soil sulfur at Lowe's or HD? I'll try that.

And the leaves are glossy green and look very healthy. I'm a little worried that they're the same type of blueberry and I'm not getting cross pollination. I would think the grower I bought from would have mentioned this, but I've read recently that you need several varieties to get good pollination. I'm thinking of adding a third plant if I can find one at this late date. I know it's too late for this year, but maybe that's a longer term solution as well as fertilizing more.

Some of the garden centers sell soil sulfur. You would need about 1/4 lb per shrub, to start. The mulch is pulled back, and the sulfur is evenly spread to cover a two foot circular area around the shrub. Then the mulch is replaced. It takes soil sulfur about one year to be metabolized by bacteria that live in the dirt. As a result, there is no immediate effect of adding soil sulfur, it is a long term solution. You can add some 5% white vinegar from the grocery store to tap water, and apply this mixture to your blueberry shrubs. This will lower soil pH immediately. Here in Madison, Wisconsin, I am using 12 fluid ounces of 5% vinegar mixed with 4 gallons of tap water. It is possible to get the soil pH too low, and kill the shrub. The soil pH should be tested before making additions of sulfur or vinegar/water, to avoid this fate. The least expensive method I have found for testing soil pH is by using bromocresol green dye indicator solution, available online from HMS Beagle. You simply dig up one tablespoon of dirt, from around the shrub, and mix it with enough distilled water to make a slurry. A clean coffee filter and plastic funnel is used to filter the slurry, and when you have a small amount of filtrate, about 1/4 teaspoon, a few drops of bromocresol green is added. The solution will turn blue, if pH is 5.4 or above. It will turn yellow, if pH is 3.8, or below. If the soil has pH between these two extremes, the solution will turn some shade of green.

Brandon right.
I live in South Carolina, so acid soil/ low pH is less of a problem.
I use Hi-yield liquid(Iron,sulphur,zinc,copper & manganese) in a soil application, but you can use it in a foliar application, too.
This way I have a balanced feeding.
A soil test would be good too.

The acidity of your soil is probably a big issue. Especially if you didn't amend it in any way before you planted. Peat moss mixed into native soil is a great way to acidify, but peat moss is a limited resource. I found sulfur in a small bag at my local Lowes sitting with all the other soil amendments and fertilizers.

Cross-pollination may be an issue in the future if you have two of the same varieties, but that won't come into play until you get flowers. No pollination occurs if you haven't had any flowers yet. From my experience, plants purchased online are generally quite small and take a few seasons until they start to flower and ultimately bear fruit.

Kim

Here is a link that might be useful: My Garden