The plums represent negative electrons
Sounds like small plums or "cherry plums". You can google plums or miniature plums to see images.
Also, Google "Hedging 'Cherry Plum" to see a picture of the hedge.
No need to worry. Worms are small creatures and if accidentally eaten can be destroyed by acid in the stomach.
The flowers of the plum tree are cross pollinated (fertilised) by visiting flying insects, beetles, and bees transferring pollen grains from flower to flower. It is not sexual in the animal kingdom sense.