Hi I have established blue berries. They have been in the ground 4 years. My soil has a lot of clay. When I planted them, I prepared them well, but now I noticed that they need a topsoil or something, because roots are scene and clay is apparent. So my question is, what should I add to the top the soil.
I would suggest mulching around the plants with pine bark or wood chips. Four to six inches of mulch would work well. This material will break down and add organic matter to the soil and you will need to apply more mulch every 2 or 3 years as the mulch decomposes. If you are fertilizing you need to increase your fertilizer rate by about 50% as the decomposition of the mulch will consume some of the nitrogen in the fertilizer. I don't think you should use the decorative mulches such as stones or recycled tires that do not break down since the decomposition of the mulch will help the soil and the blueberries in a clay site.