Tulsi maadams (an altar for tulsi plant, ocimum sanctum, holy basil) were very common in most Hindu homes even in the cities. The tulsi plant was venerated as the representation of Goddess Mahalakshmi. People were also aware of the many therapeutical properties of the plant. This site elaborates some of them.
We avidly grab the tulsi leaf prasadam at the Hanuman shrine in Shree Anantha Padmanabaha Swamy temple. We regularly add the tulsi leaves in a decoction of herbs which we drink during breakfast.
Of late, due to the apartment culture, the tulsi maadams are slowly disappearing. I was happy to see this replica of a woman drawing kolam in front of a maadam at Dakshin Chitra.
Luckily, the kolams have not disappeared yet and one sees them in front of individual apartments and at the entrance of apartment complexes. During my morning walks the opportunity to admire the various kolams on the house fronts is an added incentive.