Best Mulches for Blueberries

Asked April 10, 2017, 8:34 PM EDT

what is the best thing i could top dress or mulch over my 12 blueberry bushes in my yard. I sprinkle sulfur after leaf drop and then before bud break, but i have been using a pine mulch, but only because i thought it might help with PH. I am in Roch hills and the soil was pretty neutral before i started the conditioning.

Oakland County Michigan blueberries blueberry production soil ph lowering soil ph

1 Response

Generally we mulch with whatever we can lay our hands on. Commonly used materials in Michigan are sawdust, bark mulch, wood chips (often from grinding up trees and shrubs). Avoid black walnut if you can. Sawdust should be aged a year before it is used.
The mulching materials will do little to change the soil pH. I often recommend amending the planting hole if a homeowner wants to plant blueberries in neutral soils. If your plants are still small I recommend replanting them.
I recommend digging a hole about 2 feet wide and one foot deep and mixing that soil half and half with peat moss (about a bale per plant) if the soil is heavy mix in an equal part of clean coarse sand.
DO NOT mix manure or compost in the hole they are neutral or even alkaline and raise the soil pH. Even you are going to use sulfur apply that under the mulch. I usually mulch with bark or wood chips and you will need to remulch every 3 or 4 years. Use rhododendron azalea mix for your fertilizer. Because you are mulching heavily use a rate about twice the rate recommended. The decomposition of the much uses a lot of the nitrogen. Finally do not fertilize after July 4. We do not want the plant growing vigorously into the fall when it should be setting flower buds at the shoot tips.
Finally you should keep the plants moist into September. If the plants become drought stressed in the summer they will be stunted and set fruit poorly in the fall.