What kind of flowers are suitable for the door steps?

What kind of flowers are suitable for the door steps? It is best not to put flowers.

There is a school of Feng Shui masters in Hong Kong who do not advocate planting flowers in front of, behind, or at home. However, Feng Shui masters of this school advocate planting bamboo, but the bamboo will not bloom. The reason is: the fragrance of flowers and plants can easily attract unknown flying insects and bring unknown bacteria and viruses. Once a person is infected, it is very easy for doctors to misdiagnose and miss the best treatment time. Some bacteria and viruses are currently untreatable. Are such views available for reference?