Bunker said he expected sales to be "at least 25% up" by the end of the month.
Bunker put the uplift down to "people coming in for a reason" and "reasonable weather leading to the linger longer factor".
He says a trolleyfull of plants bought in March is generally worth £70-£80, while shoppers in peak season in May tend to spend £30-£50 when buying a trolley of plants. Bunker says: "It's quality, not quantity. Saturday was very, very good, with all departments in the whole business 10% up."
Sunday last year was Easter Sunday so is not comparable, but Bunker says Mothering Sunday was 20% up on last year.
Alton's gives away 150 primroses from Woodlark Nurseries in a zinc pot to mothers who order a lunch in the restaurant.
Bunker said he sold 50 batches £25-£30 polygallas at the weekend, half for Mother's Day, adding: "We've sold something of everything."
He added: "March weather has worked in our favour. We have forward momentum and Mother's Day has carried it on."
Green Pastures owner James Debbage said his restaurant was booked out on Saturday and Sunday and "sales were significantly up on any other weekend we have had".
Bord na Móna head of commercial UK Steve Harper said: "Sales are increasing rapidly compared to last year."
Data from Halifax has found credit card spend over the weekend of Mothers’ Day (Friday, Saturday and Sunday) has grown from £69.6 million in 2014 to £71.9 million in 2015, before reaching £75.6 million in 2016. This represents an average rate of annual growth of 4.2%.
Halifax expected Mothers’ Day weekend card spending to reach £79 million this year.