I heard of a growing medium called pinefines. Have you heard of it? Where do I get it?
Montgomery County Maryland
Pine fines is shredded, aged pine bark and it is typically used to help acidify soil (for acid-loving plants such as azaleas, rhododendrons, etc.). It is also good for adding organic matter and improving drainage, especially in clay soils. You can find it with other mulches in most garden centers and hardware stores.