Rowe was speaking on a conference call following the retailer’s full-year results, which show that it continues to face rough seas across both businesses.
In food, total UK sales for the year ending 31 March grew 3.9%, but like-for-like sales fell 0.3%. In clothing, sales fell 1.4% total, and 1.9% like-for-like. In both cases, results worsened each quarter.
Total revenue for the business was up 0.7% to £10.7bn, but profit before tax fell 62% to £66.8m.
M&S yesterday announced that 14 stores are set to close by next year in a wider plan to shutter 100 stores by 2022, as it seeks to rebalance its business to reflect more shoppers moving online.
The retailer announced last month that top marketer Patrick Bousquet-Chavanne and his deputy Rob Weston would be leaving the business, with marketing responsibility divided between Sharry Cramond, for food, and Nathan Ansell for clothing and home.
But Rowe denied this meant the two businesses would be fully divorced.
"M&S is a family of business united by a common brand, values and culture," he said. "There will be a time and place for that to be one campaign.
"We have 32 million customers and the vast majority shop across both businesses. Customers appreciate that we’re one brand.
"What we want to do is make sure we have leaders of each business with clear autonomy. We need to make sure those teams reflect the right marketing stance to trade those businesses."
The food business has been the star performer for M&S in the last decade, generally recording impressive growth while clothing & home has been in long-term decline.
Rowe admitted the food business had "underperformed" and pointed to a number of factors, including operational problems that affected the availability of products. But he also said some of the product innovation had been "too niche", adding: "We need to make sure our food business is more relevant to British families."