The trust put laid the blame at the door of London Mayor Sadiq Khan, who withdrew Mayoral guarantees for the project in April, saying further support would expose London taxpayers to too much financial risk.
In a statement issued today, the trust said it "has had no choice but to take this decision because of lack of support for the project going forward from the Mayor. We would like to thank all our donors and supporters who gave us unstinting support and encouragement along the way."
Growers and contractors should be compensated for work done on the Dan Pearson-designed garden. Thomas Heatherwick designed the £200m bridge, which attracted oppostion, mainly for needing public funds. Palmstead, Deepdale and Willerby's were among industry firms involved.
On 28 April, Sadiq Khan wrote to Lord Mervyn Davies, chairman of the Garden Bridge Trust, stating that he was not prepared to sign the guarantee for the annual maintenance costs of the bridge, a condition of planning consent, "despite previous assurances given about his support for the project".
At the time Davies said the board was still confident the trust could raise the money needed for the project to proceed.
Since then the Garden Bridge Trust has examined in detail all options available to it. This included discussions with a potential benefactor who was keen to provide the required guarantee. It also had further discussions with the Government.
The benefactor concerned and the trustees have all concluded that they cannot proceed without the support of the Mayor of London. Davies said he had raised £70m of private cash for the bridge.