Known as the Douglas Chalk Collection, the plants were assembled in the 1930s by Chalk, an enthusiastic plant hunter and former student at the college.
"They used to be at Heaselands Estate nearby" said grounds manager Alan Phillips. "This brings it full circle." The 83-strong collection is recorded on a database to ensure continuity, he added.
The college has also been growing the rare black poplar (Populus nigra) for nearby Wakehurst Place, part of RBG, Kew.
According to Phillips: "They have been propagated from the remaining 34 trees in Sussex and will be planted out locally."