[1] After attending high school, Allard studied under Alexandre Boreau, the director of the jardin des plantes d'Angers.

In 1863, Allard became a member of the Société entomologique de France and voyaged to Algeria, Spain, and Portugal to study Lepidoptera and the regional flora.

[2] After the death of his father, he inherited the family estate and developed the gardens.

In 1885, he dedicated a polyantha rose variant to his father-in-law, named the 'Daniel Lacombe' [fr].

[5] The botanist Louis Blaringhem, his colleague from the Pasteur Institute, succeeded Allard as arboretum director.