Hi! Thanks for your response.
I didn't bother because every 6-pack of annuals I've bought for the past 5-6 yrs had styro in it. I wasn't going to drive 45 minutes away to hope that wasn't the case this year, then go home empty-handed and also $10 poorer for the gas it took.
I object on several fronts. First, it's trash, I don't want bits of any kind of trash being purposely buried in my yard, I don't live in a landfill. Second, it does nothing to 'amend' soil. Third, it's ugly to look at. Fourth, unless picked up, it just stays there indefinitely.