Hi
I agree the gardens do look unkempt. We had a similar problem here in our village in UK. We have a community garden " Millenium Garden" it becam very neglected. Complaints were made to local council. Our council tax is one of the highest in the UK. The council made all the right noises but did nothing.
Local villagers got together and "volunteered" their time. A rota system was put in place so all we need to do is 2 hours every 6 weeks and the garden looks lovely. The gardens in san Cayatano are bigger so more of a commitment may be required? Volunteers? I would be prepared to help whenever I was in Spain, although my not living there would be restrictive.
Our voluntary clean ups are a great source of community spirit and have become a bit of a social event.
I'm not advocating local authorities not fulfilling their responsibility to our communities both here in UK and Spain. Not at all but if we were still waiting for the council to do something here our garden would be an overgrown mess!
Just an idea!
Take care.