Many Hindu paths will use a personal altar in their daily worship. Those altars often include pictures of their spiritual teachers. Buddhists do this also. And flowers are, of course both beautiful, smell beautiful and are a source of inspiration.
So, a "meditation on a flower" is really just a meditation on God's beauty and purity.
If folks get hooked into some odd construction of phrasing...as is likely when the teacher is not a native English speaker....it is easy to mistake the literal for metaphor and the reverse.
People get freaked out by the notion of cults and start ascribing every single strange and weird idea to every innocent action or teaching by anyone from a different culture.
One really has to take time, learn the culture...and then, one understands that the teachings are just a re-phrasing of all the teachings from the Hindu tradition, since time immemorial.
The Yogi Lahiri Mahasaya also taught his students to "meditate on his picture" --- and before there was photography, teachers taught their students to meditate on the image of God - as embodied in a sculpture or drawing...saying that, in deep meditation, one can go beyond form and find the living presence of God, even through such a representation.