The artist grew up in Kyiv and was inspired to paint by the views of the Dnieper River and surrounding landscapes.
He studied in the workshops of Ukrainian artists Nartsis Kocherezhko and Vasyl Korchynskyi.
His paintings often depict still life, sea horizons, city and natural landscapes.
Mr Nekrasov’s work features in many private collections across Europe, as well as appearing in international exhibitions.
The painter, who spoke to the BBC through a translator, said leaving home had been very difficult.
Once in the UK, he was inspired to paint “beautiful places in England, mixing grey colours with bright colours was very interesting”, said Mr Nekrasov.
“I started working in the Fullers Mill in spring and have seen the colours change from spring to summer, which was incredible,” he said.
“I like mixing colours and shadows, it’s the basis of painting, colour is life.”
Jude Law, the Ukrainian family’s host, was surprised when she found out Mr Nekrasov was an established artist.
She showed one of his paintings to Peter Newman, chief executive of Perennial, the charity which owns and maintains Fullers Mill, and he was “enamoured” by it.
Annie Dellbridge, the garden manager, said: “It’s amazing the way he captures the whole garden, not just in the image, but actually the feel of the garden too.
“We’re really pleased that he’s agreed to work with us.”
A percentage of the proceeds from the painting sales will go to the hospitals for the National Guards of Ukraine and to Perennial.
The exhibition will run until 24 September, from 14:00 to 17:00 BST on Wednesday and from 11:00 to 17:00 Friday to Sunday.