Are the house plants significant?

I couldn't ignore them once I started noticing. The temperate tree in the corner of the consulting room was almost bigger than those, more tropical, plants in John's office. Was it a cactus or a succulent, the first present for Cynthia/Cindy? it was the smallest plant and provided a link between John, Cynthia and then Ann.
The hanging basket can't have been so comfortable on his privates. It was an imaginative and appropriate guesture, considering Cynthia's love of plants, but surprising coming from the self-centred John. It endeared me to him; life with Ann must have been a bit of a trial, bit like life with a limpet. I didn't believe Ann's story, to the therapist, blaming John for her lack of interest in sex. The contrast between the sisters is stark if their respective domestic arrangements are anything to go by.