The Humboldt Botanical Garden is a 44.5 acres (18 ha) botanical garden located four miles south of Eureka, California, United States. The Garden is near the South Bay portion of Humboldt Bay on the north side of the College of the Redwoods. Grading and site preparation began in August 2003. Featuring views of Humboldt Bay and the Pacific Ocean, the garden opened in 2006, with more development completed by 2008.
The Humboldt Botanical Garden (HBG) business office is located in downtown Eureka and is operated by the nonprofit Humboldt Botanical Garden Foundation which had over 1000 members in 2020 HBG is a member of the American Public Gardens Association, the American Rhododendron Society, and the American Horticultural Society Reciprocal Admission program.left|thumb|upright=1.4|One of the wild areas of the gardens, 2013.
The garden is "a repository for many rare and hard to grow rhododendrons and their companion plants" according to a local office of the American Rhododendron Society. HBG is listed by the California Native Plant Society as one of the 17 California gardens with notable California native plant collections.thumb|upright=0.7|left|[[Meconopsis betonicifolia similar to that found at HBG in the Temperate Woodland Garden. The area's climate, which straddles Mediterranean and Pacific Marine Rose Garden; Heather Garden; Pollinator Garden; Mediterranean Allee and Native Tree garden; plus five miles of hiking trails.
The Humboldt Botanical Garden is particularly interested in maintaining complete native conifer, Iris and western lily (Lilium occidental) collections. Its Mission Statement is: To cultivate a garden that provides an enjoyable discovery into the botanical world through education, participation and community service.
A summer music series and an annual native plant sale are held in the gardens. The gardens are available as a special events venue.
In March 2023, HBG became the northernmost site for safeguarding the state-listed endangered species Vine Hill manzanita (Arctostaphylos densiflora) which is native to Sebastopol, Sonoma County, California.
Another critically endangered species is the Wollemi pine (Wollemia nobilis), a native of Australia which has been planted at HBG.
thumb|upright=1.1|Humboldt Botanical Garden native plants
Research
Active research in support of conservation, general research, and education is supported. As of 2024, this has included research into Monterey Pines (Pinus radiata), habitats for native pollinators and their flower selection, removal of invasive species, and studying the effects of potential predation on foraging habits of bumblebees.