Ericoid Rx Mycorrhizal Inoculant & Soil Amendment For Garden, Mycorrhizae Root Booster for Azaleas, Blueberries, Camellias & Rhododendrons, Root Stimulator & Soil Inoculant for Healthier Growth(16 oz)

Only giving 3 stars because the marketing scheme of saying to reapply every2-4 weeks when fungi innoculates once.

I have not used this long enough to know if it helps. I can tell you, the spores are viable. I have observed Tiny hairs growing looking for roots within a day or two of adding to my BLUEBERRIES. This is one of the few made for use on BLUEBERRIES In acidic soil.Happy customerTime will tell how much they helpEdited to addI am now a repeat customer. I could not find this item for a while. When it reappeared, I purchased immediately. The bag looks like it's fresh out of production with 2 full years until the expiration date.I purchased 8 tiny little blueberry sprouts last summer. I did not expect half of them to make it through the winter. They all survived and are currently thriving. Blueberries benefit from REPEAT APPLICATIONS unlike other forms of mycorrhiza that only need to bond once. I believe this product does irs job. I hope they continue to make it.