The private foundation has specified the money is for one of the gardens on the bridge, on the north landing, with views on to The Houses of Parliament and the London Eye.
The Taylor Family Foundation supports charities and organisations helping children and young people in the areas of education, health, recreation and the performing arts. Established in 2007, its patrons are Ian and Tina Taylor. Ian is also president and chief executive of Vitol, one of the world's largest independent oil and gas trading companies.
It will cost £175m to deliver the Garden Bridge project. More than 65 per cent of the capital costs to build the bridge will be raised from the private sector. The trust says it is well on its way to meeting its target, with £140m pledged so far.
However public funding of the bridge is still controversial, with Transport for London and the Treasury each pledging £30m towards the bridge. London Mayor Boris Johnson has also promised to underwrite emergency and maintenance costs in case the Garden Bridge Trust is not able to meet pay its annual maintenance bills.