According to
Étienne Pierre Ventenat, who named the Australian woody scrambler
Kennedia to honor John Kennedy, the firm supplied roses for the
Empress Josephine at
Château de Malmaison during the lull in the Napoleonic Wars provided by the
Peace of Amiens, 1802-03. Josephine's head gardener at Malmaison, Howatson, was English, but Alice M. Coats suggests that it was probably the well-established Scottish gardener and landscape designer,
Thomas Blaikie, who put her in touch with Lee and Kennedy; her relation with a London-based firm was one of the curiosities of garden history, according to Coats. By 1803 the Empress had run up an outstanding bill with them of £2600. She helped them support a young plant hunter, James Niven (1776–1827), at the
Cape of Good Hope, in expectation of sharing boxes of seeds and plants of never-before-seen rarities of the scarcely botanized
Cape Province:
heaths,
ixias,
pelargoniums and others. With the revival of war between France and Britain, John Kennedy had a special permit to come and go to the Continent, advising the Empress on the collection she was forming at Malmaison. There were setbacks: in 1804 she complained in a letter that shipments of seeds had been captured and detained; but in 1811 her expenditures with the firm again amounted to £700. At Malmaison, she installed a plant nursery, to ready her imports for distribution among French growers. Towards the end of the
Napoleonic Wars, Tsar
Alexander I and three of his family visited England. Grand Duchess
Catherine Pavlovna, young widow of the
Duke of Oldenburg, made a point of visiting Lee and Kennedy's nursery grounds at Hammersmith, reputed to be a magnet for any garden-minded visitor. Lewis Kennedy arranged for the appointment by Bryan Salvin of his brother John Kennedy (1719-90) as gardener on £30 a year plus accommodation at
Croxdale Hall in
County Durham. John worked there between 1748 and 1771, (before moving on to
Parlington Hall) and from 1750 regularly ordered trees and plants from his brother's nursery for the three walled pleasure garden the Salvin family had him create. == Retirement and succession ==