Hundreds of flowers have been swiped from Sandall Park in recent weeks and now volunteers are clamping down on the thefts.
A spokesman for Friends of Sandall Park, the volunteer organisation which looks after the park, said: "You will notice there are not many daffs in the park - this is because they have been stolen.
"Yes it is theft. Children and adults have been seen with armfuls.
"Many are just thrown down on the ground once they've been picked.
"They do not grow naturally in Sandall Park and those that are there have been planted by us."
Flowers growing in council parks are legally off-limits and the same goes for council-maintained displays on roundabouts or verges or any gardens planted by a particular organisation, nature reserves or protected land.
The rules are slightly different regarding wild flowers.
According to Dominic Price of wild plant protection charity Plantlife: "It is not normally an offence to pick the 'Four Fs' – fruit, foliage, fungi or flowers – if the plants are growing wild and it is for your personal use and not for sale."
Dozens of rare or endangered plants – from the lady's slipper orchid and adder's tongue, to threadmoss and sandwort – are, however, protected under the 1981 Wildlife and Countryside Act.
Added the FOSP statement: "The conclusion? If in doubt, save yourself the trouble and head to your local florist."