Possible Clues:

• Colourful digits useful in the nursery
• It's like Olive to recognise skinhead has attributes for career in garden centre
• Natural ability as a gardener
• Talent for gardening
• Inexperienced hands reveal growing talent
• Colourful evidence of skill in bed?
• Gardening skill
• Special ability to grow plants
• They will give you a bit of a hand in the garden
• Horticultural skill (or luck?)