Vandalism

I am gutted.

You know I spent quite some time designing, building and planting my xeriscaped border outside my house as a contribution to my neighborhood, country and environment. Unfortunately, some vandals – most probably kids who go to the school opposite my house – continue to wreak havoc in it by willfully damaging the plants.

Here are just some of the heart-wrenching results of their labors:

I will survive! vandalized cactus plant

and these taken yesterday:

vandalized cactus plant

The question I have is why? Why do they have to do this? They throw rocks at the lovely plants and just walk away. What do they actually get out of it?  And what can I do to prevent them from doing this?