initially the gardener didn't knew the results of his plants but later he found that plants due to variations led to difference in traits .
which produced plants with larger flower and plants with smaller one
later with the passage of time larger flower become a survival advantage or it was artificially selected which lead to increase in the no. plants with larger flower resulting in decrease in no. of plants with small one.
speciation occured as their were traits present one with larger flower and other with smaller one.
as plants with larger flower tend to have a survival advantage the naturally selected this trait . thank you.