fences that are near to it the bad luck starts when u pick the flower.this bad luck causes u you u drop plates and cups that are breakable. is this true? and if it is which flower is it?

There is no such thing as bad luck plants. Only if it is poisonous and you eat it, can a plant actually cause you bad luck. Treat all those myths with skepticism, good and bad luck is in your own mental attitude.

There is a plant with purple flowers that looks a little like a potato plant and it then goes on to produce purple shiny berries about 2mm in diameter. Yes it IS bad luck to pick this one as it is called woody nightshade and is the second most poisonous plant in the uk.
With regard to cups and saucers etc. i really think you need to take some things with a pinch of salt.

Better stay away from purple flowers, huh??