trashing my yard?

hi, i'd love some feedback from those of you who live in homes in the cd, south of cherry.

i moved to the cd about a year ago (after renting on south cap hill for 20 yrs).  we really love our house, neighbors, and neighborhood (we're a few blocks from garfield).  we've met many of the people on our block, and have even had nice conversations with people from a few blocks away--so i feel pretty good about the people who live near us.

however, we've noticed that since we started working on our yard--general clean-up and planting a few flowers and bulbs--we regularly come home to some sort of yard vandalism.  first, it was small bits of trash (wrappers, etc).  a few days ago, someone pulled out one of my plants, threw it on the sidewalk, and kicked dirt all over the place.  tonight, i came home to large amounts of trash on the lawn, and one of our plants knocked off of our porch and crushed on the walkway (very upsetting to my young daughter, as she was the one who potted that plant).

at first, i chalked up the random trash to garfield teens (who often park on our block, and sometimes eat lunch in their cars).  now, i'm wondering if we've become a target because we're trying to make our yard look nice??

i know this sort of stuff happens to some degree in every neighborhood.  but we've never owned a home, or lived in a single-family dwelling in the 21 years that we've been in seattle.  our experience is limited to apartment dwelling.  i'm wondering if this is something that others experience on a regular basis in this neighborhood.  if i'm making myself a target by trying to pretty things up a bit (and i really mean a bit--a handful of daffodil bulbs, some ornamental grasses, a lavender plant), then i'll know to minimize my front yard care and focus all my work on our (fenced) back yard.  i don't want to have to fence our front yard, too, but it's something i'd consider down the road if needed.

thanks for any advice.