Claudio Contreras / Texas indigo snake (Drymarchon melanurus erebennus) close up amongst Vervain (Glandularia sp.) flowers, Laredo Borderlands, Texas, USA. April

Tim Fitzharris / Vervain (Verbena officinalis) at Franklin Mountains State Park, Chihuahuan Desert, Texas

Loic Poidevin / Large White butterfly (Pieris brassicae) feeding on Verbena (Verbena bonariensis) flower, Vendée, France. August.

Loic Poidevin / Scarce Swallowtail butterfly (Iphiclides podalirius) on Buenos Aires Verbena (Verbena bonariensis) flower, Vendee, France. July.

Ingo Arndt / Mata negra (Mulguraea tridens) flower. Torres del Paine National Park, Patagonia, Chile. December.

Heather Angel / Honey bee (Apis mellifera) nectaring on freshly opened yellow Lantana (Lantana camara) flowers. Flowers turn pink when nectar no longer provided. In garden, Tanzania. Native to tropical Americas.

Heather Angel / Wild sage (Lantana camara), flowers turn pink following pollination. Native to tropical America. Invasive species, Tanzania.

Heather Angel / Wild sage (Lantana camara), flowers turn pink following pollination. Native to tropical America. Invasive species, Tanzania.

Ernie Janes / Argentinian vervain (Verbena bonariensis) and Giant feather grass (Stipa gigantea) in garden border.

Ernie Janes / Spider flowers (Cleome hassleriana) and South American vervain (Verbena bonariensis) cultivated plants growing in garden, Norfolk, England, UK, August.

Nick Upton / Chaste tree / Chasteberry / Monk's pepper (Vitex agnus castus) flowering in Zakros gorge, Sitia Nature Park, Lasithi, Crete, Greece, May 2013.

Claudio Contreras / Texas indigo snake (Drymarchon melanurus erebennus) amongst Vervain (Glandularia sp.) flowers, Laredo Borderlands, Texas, USA. April