After spending time as a banker and teacher in London and Sussex, he came to national attention for his botanical articles and books, and was renowned for his landscape gardening work in Brighton during its period of rapid growth.
His grandiose Anthaeum project, an elaborate indoor botanical garden topped by "the largest dome in the world",[1] ended in disaster when the structure spectacularly collapsed just before its official opening.
The first 40 years of his life were spent in London and Sussex: he worked for a bank in Worthing and lived in the town, then moved to Brighton with his wife, Elizabeth Willmer who he had married on the 18 December 1800 at Petworth.
[11] In early 1831, the Brighton Herald newspaper stated that Phillips was due to sail on 1 February of that year to Caracas, where he would be appointed as the official botanist of Simón Bolívar's estate.
[11] On the 27 January the Sussex Advertiser reported that Mr Henry Phillips, senior, of Brighton one of the most active supporters of the Anthaeum is now confined to Horsham Goal, "the fall of that noble structure is understood to have caused the pecuniary difficulties which led to his imprisonment.
[11] In 1825, Phillips worked with Amon Henry Wilds again on an ambitious scheme to build a seafront square whose north side would be occupied by the Athenaeum—an exuberant Oriental-style glass and iron conservatory housing plants, a library and other public attractions, set in landscaped grounds.
Launching his scheme under a slightly different name, the Anthaeum (meaning flower-house), he secured land and finance from Sir Isaac Goldsmid, 1st Baronet and engaged Amon Henry Wilds as architect.
[11] The site provided by Goldsmid was in Hove, then a small town west of Brighton which was beginning to develop as a fashionable residential area: the Anthaeum was built immediately north of Adelaide Crescent, on which work had started in 1830.
[1][11][30] Inside the dome, which enclosed an area of more than 1.5 acres (0.61 ha),[11] Phillips planned an exotic garden with tropical trees and plants, unusual shrubs, a lake, birds and other features,[31] "not unlike the modern Eden Project in Cornwall".
English, whose decision not to build the intended central supporting pillar led to Hollis and Wilds abandoning the project, continued working with no proper supervision for several months,[33] despite Phillips' concerns; and on 30 August 1833, the day before its official opening, the Anthaeum spectacularly collapsed: "the immense ribs of iron snapped asunder ... and a great part of [the structure], from the height it fell, was buried several feet deep in the earth".
[11] Phillips' books and other publications included:[3][5][34] Pomarium Britannicum, subtitled An historical and botanical account of fruits known in Great Britain, ran to three editions published between 1820 and 1827.
[1] When Brighton and Hove City Council restored the gardens and grounds of the Royal Pavilion to show how they would have appeared at the height of the Regency era, they did so according to Phillips' ideas—specifically his belief that "a well-planted shrubbery depends on the selection of trees and shrubs which succeed each other in blossoming throughout the year, as well as contrasting shades of green ... and under-planted flowers".