Police are appealing for information after thieves took about 30 plants from public gardens in Bakewell last week.
The theft took place just two days before judges were due to visit the town for the East Midlands in Bloom competition.
Around a dozen plants were stolen from the sensory garden where they had just recently been placed and a further 20 plants were
taken from assorted bedding in Bath Gardens.
Carnations, lavender, rosemary, thyme, oregano and agapanthes were stolen from the sensory garden, where plants are chosen especially for their ability to stimulate all senses.
Cllr Frank Hall said: "Someone removed them very carefully and deliberately.
"I don't think it was to sabotage the town's chances in the competiton, otherwise why not just vandalise the place?"
However, Cllr Hall said there was a positive aspect of the plants being stolen because it showed people's dedication to the town's environment.
He added: "After the theft on Wednesday I went down on Friday morning before the judges arrived and I found three U3A (University of the Third Age) volunteers on their hands and knees, replacing the plants.
"All U3A members are over 60 and there has been no budget for the competition, so they would have paid for the replacement plants themselves. I also noticed that the district council replaced those stolen in Bath Gardens."
