Crookes said root-wrapped hedging that has not been planted out, weathered displays, "unshoppable" groups of shrubs and "half-dead yuccas" dumped at the back of planterias are problems that he encountered.
He added that aquatics and other concessions need to get up to GCA standards to match their landlords.
Other planteria issues highlighted by Crookes included specialist plants with poorer point of sale than "bog standard plants", broken straps on the tables of baby change facilities and pots stacked too high to be shoppable. He also noted that some retailers are squeezing aisles too close together.
The final GCA awards are due to take place in Dumfries on 22 September.