I'm wondering if the shrubs are a citrus, they can look yellow if lacking nutrients and those shrubs look to have been cut back a lot. I've tried growing several types from seed, all lost now, one was years ago from a fruit which was a mandarin cross grown in Brazil which was called something like Mandora, that got big very quickly and had outgrown it's large pot so started to suffer, it also got covered in scale insects so I left it outside to the elements.
http://aromasvitais.blogspot.c...
Look at the similarity of Citrus aurantium ..
http://www.public.asu.edu/~cam...
It would have trouble flowering with being cut back so much, the flowers you can see look like they belong to the vine.
