@Samstamport -- are you looking for financial support? or just approval to be allowed to create some plantings?
In either case, I would suggest writing up a formal proposal stating what it is that you would like to do, and then present it to the city council and any local association of businesses (for instance, the town that I'm near has a "downtown development authority"). Or the Chamber of Commerce. There may also be grants available from the state or federal government, which I admit to knowing nothing about how to obtain.
And, I agree with Rick -- phrase your proposal in terms that will offer a benefit to the city and to the businesses!