Hume took an interest in wild plants and especially on invasive species although his botanical publishing was sparse with only a few short notes in 1901 on a variety of "Scirpus maritimus" and another on the flowering of "Impatiens roylei". Hume contacted W.H. Griffin in 1901 to help develop a herbarium of botanical specimens. Hume would arrange his plants on herbarium sheets in artistic positions before pressing them. The two made many botanical trips including one to Down in Kent to seek some of the rare orchids that had been collected by Darwin. In 1910, Hume bought the premises of 323 Norwood Road, and modified it to have a herbarium and library. He called this establishment the South London Botanical Institute (SLBI) with the aim of "promoting, encouraging, and facilitating, amongst the residents of South London, the study of the science of botany."