Both Birch hotels have fallen into administration, three years after the opening of the first site.
The Birch Cheshunt hotel in Hertfordshire has closed with immediate effect, while the Birch Selsdon in South Croydon is trading under the control of administrators.
Moorfields Advisory Limited said it was appointed as administrator to the Selsdon hotel on 17 November after the property ran into difficulty due to "cash constraints".
The 140-room Birch Cheshunt opened in 2020 and featured two restaurants overseen by chef Robin Gill, as well as a farm, three bars, 20 event spaces, a bakery, fitness studios and screening rooms.
An announcement on the Birch Cheshunt website said administrators at Teneo had closed the hotel.
"We are very sad to share this disappointing news and apologise for the obvious distress and disruption to our members, guests, suppliers and the great employees," the statement said.
In an Instagram post, Gill said the team had to "down tools with immediate effect yesterday [20 November]".
"I believe this is strictly a financial hit due to a lack of funds required for reinvestment into the sites that was needed to bring the properties up to standard," he wrote.
Gill said he had a "fantastic team" who are now unemployed and could "do with some help finding work".
"I'm assuming [the hotel is] now up for sale at a fraction of what the owners would have liked to sell it for and needs some love from investors with vision and passion to get it to where it needs, and deserves to be," he added.
Birch Cheshunt took over the site once occupied by the De Vere Theobalds Estate hotel and was originally overseen by the former managing director of the Ace Hotel London, Chris Penn, and entrepreneur Chris King, both of whom left the business last year.
It was a joint venture between Penn and King's management company, Performance Hotels, and owner Aprirose, the real estate investment company that bought the property in 2018, with £8.5m invested to transform the site.
The 181-room Birch Selsdon launched in Croydon this spring under current managing director Ayo Akinsete, with two restaurants overseen by chef Lee Westcott.
It is understood the hotel remains open while administrators work on a potential sale.
A Birch Selson member told The Caterer: "The gardener is on reception and they have let go of all the zero hours people. The lido is shut too. The animals are going back and we are told they will know by Friday exactly what is happening."
Milan Vuceljic, partner at Moorfields, said: "The Birch hotel group had a unique market proposition, which fitted with today's health and wellbeing culture whilst still boasting a Greater London location.
"We are currently continuing to trade the hotel whilst we explore various options, which we believe provides a good opportunity for potential purchasers."
The Caterer has contacted Birch and Teneo for comment.