Ilkley in Bloom is asking people to look out for thieves taking plants from flowerbeds around town.
The voluntary group is preparing for the visit of the Yorkshire in Bloom judges on April 16 but says flowers have been taken from two areas its members have planted.
Plants were dug out of a trough near the Old Bridge, and more were taken from a trough in the South Hawksworth Street car park.
Ilkley in Bloom raises money itself for plants, to improve the appearance of the town, as well as boost Ilkley’s chances in Yorkshire in Bloom.
The group is also calling on dog walkers not to let their pets foul a wildflower area in Bolton Bridge Road.
A litter pick is being organised by Ilkley in Bloom on Tuesday before the Yorkshire in Bloom judges visit.
Volunteers are asked to meet in the central car park at 6.30pm to help out.