The poppy, which cost £750, will join a scrapbook diary with pressed flowers of a machine gun core soldier's journey from Salonika - now called Thessaloniki in Greece to Serbia, donated by a relative. The London museum has used the flowers from the front as a starting point for an exploration of the effect World War One had on parks, gardens and memorials and how horticulture influenced life during World War One, from the home front to the Western Front.
Curator Russell Clark said exhibition will also look at the difference that thousands of gardeners leaving their occupations to fight had on large estates and public parks as well as those historic designed landscapes which were dug up to for food production. The huge loss of man power led to many women taking up gardening.
The museum is also working with the RHS to tell the story of the British interned at Ruhleben in Germany, where three quarters of the interned civilians joined the horticultural society.
The exhibition runs from 1 October to Christmas and is supported by the Heritage Lottery Fund.
- Alan Titchmarsh's 50 years of gardening: A personal history of gardening in 101 objects runs at the Garden Museum until 31 August.