The Chinese billionaire's empire came under heavy official scrutiny after a speech in October in Shanghai, which accused the regulatory system of stifling innovation, and the blockbuster $37 billion IPO of his fintech affiliate Ant Group was suspended.
Ma, once China's most famous and outspoken entrepreneur,
had been "lying low" and focusing on hobbies and philanthropy, Alibaba's executive vice chairman and co-founder Joe Tsai told CNBC in June.
He reappeared in Hong Kong in October, where he met at least "a few" business associates over meals, two sources told Reuters.
He then flew to the Spanish island of Mallorca, where his luxury yacht is anchored, his first trip abroad since he fell out with Chinese regulators, two Spanish newspapers reported last week.
Marco van Herk, commercial director at Dutch flower company Anthura, said on Wednesday he had been expecting to give a tour to a group of Chinese business executives earlier this week.
"We were totally surprised when Jack Ma stepped out of the car," Van Herk told Reuters. "He was very interested on a personal level. We talked about how they (orchids) could smell great and were beautiful at the same time."
Ma wanted to know all the details about the cultivation of the flowers. "We also focus on robustness, which is right up his alley because you get into how to offer a plant online packaging, rather than out of a store."
Ma visited several other business and research centres in the Netherlands, including the World Horti Center.
He was photographed in a baseball cap, wearing a white protective gown and holding flowerpots, while in another picture he is seen in jeans and a hoodie.
The billionaire, who retired as Alibaba's chairman in 2019, will continue touring European companies and research institutions involved in agricultural infrastructure and plant breeding, according to the South China Morning Post (SCMP) newspaper.
Ma believed combining the technology he researched with Alibaba's cloud computing, big data analysis and artificial intelligence could help modernise Chinese agriculture, people familiar with the trip told SCMP.
On Sept. 1, photographs of Ma visiting greenhouses in eastern Zhejiang province, home to both Alibaba and Ant, went viral on Chinese social media.
The next day, Alibaba said it would invest 100 billion yuan ($15.5 billion) by 2025 in support of "common prosperity", becoming the latest corporate giant to pledge support for the wealth sharing initiative driven by President Xi Jinping.
"I don't know if it will lead to any business, but it was valuable just to have him here," Van Herk said.
(Reporting by Donny Kwok and Anthony Deutsch; Editing by Lincoln Feast and David Holmes)