Surface-enhanced Raman scattering (SERS) effect was used to demonstrate ultrasensitive optical detection of nucleic acids. In this work, the SERS spectra of seven genomic DNAs from leaves of Arnica montana (L.), Fam. Compositae, Astragalus peterfii (Jáv.), Fam. Fabaceae, Kalanchoe x hybrida, Fam. Crassulaceae, strawberry (Fragaria x ananassa Duch.), Fam. Rosaceae, carnation (Dianthus caryophyllus L.), Fam. Caryophyllaceae, apple (Malus domestica Borkh.), Fam. Rosaceae and Persian violet (Exacum affine Balf.), Fam. Gentianaceae were analyzed in the wavenumber range 200–1800 cm−1. SERS signatures, spectroscopic band assignments and structural interpretations of these plant genomic DNAs are reported. SERS spectra of nucleic acids are compared here with caution, because these signals are time-dependent. The SERS spectra corresponding to DNA from Arnica, Dianthus, Fragaria and Kalanchoe leaves show well-resolved, accurate bands, providing thus a high molecular structural information content. Based on this work, specific plant DNA–ligand interactions or DNA structural changes induced by plant stress conditions associated with their natural environment might be further investigated using SERS spectroscopy. Besides, this study will generate information that is valuable in the development of label-free DNA-based nanosensors for chemical probing in the living cell. Copyright © 2011 John Wiley & Sons, Ltd.