If you had any doubts about how much a potting mix affects plant growth, here is your evidence. The 'Marie Pavie' cuttings on the left were planted in Foxfire farms mix. The one on the right was planted in Promix HP. These are just 3 samples from the 8 cuttings taken on 6/15/2014, and the results are consistent. Same results with the rosemary cuttings. Hard to find the Promix HP, however.