- Arnold Arboretum of Harvard University
- International Lilac Site
- International Lilac Society
- New England Wild Flower Society
- New Hampshire Department of Agriculture - Division of Pesticide Control
- New Hampshire Department of Agriculture - Plant Industry
- New Hampshire Division of Forest and Lands - Urban Forestry Center
- New Hampshire Division of Forest and Lands - NH State Forest Nursery
- New Hampshire Moose Plate Program - Supporting conservation and cultural heritage
- Society for the Protection of New Hampshire Forests
- University of New Hampshire Cooperative Extension
- Wentworth-Coolidge Mansion - Site of the first New Hampshire lilac planting