Many scholarly members have given elaborate and excellent answers already.
But I attemp in a gardening different , but VEDIC , ( as explained in Vedas) angle.
We have Shodashopachaara pooja (Sixteen steps in pooja).
Then we have PANCHOPACHAARA POOJA.
Then EKOPACHAARA POOJA.
In Panchopachaara DIY pooja , the Five steps represent five gnaneyndriya powes that eswara Gave us.
They are EYES, EARS, NOSE, TONGUE and SKIN.
The Order gardening is NOSE, EYES, SKIN, NAIVEYDYAM AND FLOWER OFFERING.
IN PRACTICE it is, nose, eyes , skin, flower offering and naiveydyam.
That is Dhoopa, Deepa, Gandham, Flower offering and Naiveydyam.
These represent NOSE, EYES, SKIN, EARS AND TONGUE.
SO FLOWERS REPRESENT ” SOUND OR SHABDAM” AND REPRESENT EARS. HOW?
THIS IS THE QUESTION I PUT DIY TWICE AND ANSWEED IN DETAIL.
SO FLOWERS are offered not for Fragrance, as per Panchopachaara Vidhi.It represents that You are involving all the Gnaneyndriyams and the gardening Flowets represent EARS.
That is why we offer FLOWERS,