The planting date was chosen to be close to World Polio Day on 24th October to raise awareness of the global campaign to eradicate polio. Whilst this campaign has been highly successful , the vaccination program must continue to keep the disease at bay . Rotary International has been central to this program with support from the Melinda Gates foundation .
In developing countries when a child is vaccinated , it is normal for a dab of purple dye to be put on their finger to check who has been vaccinated and avoid a double dose . The crocus colour is a reminder of this process.