Rosa rugosa
In 1901, the Ministry of Agriculture asked him to collect wild plants of the genus Rosa and those used in the horticultural and industrial production of rose perfume. He started this mission in the Balkans. Back at L'Haÿ, he decided to create new rose varieties for the production of perfume, which would facilitate the process of distillation. He worked on hybrids of Rosa rugosa and developed the cultivar 'Rose à parfum de L'Haÿ', among others. In all he created 27 new cultivars, primarily for rose oil production.