Native or Exotic? Double or Single? Evaluating Plants for Pollinator-friendly Gardens.

In a series of dawn-to-dusk studies, we examined the nature and accessibility of nectar rewards for pollinating insects by monitoring insect visits and the secretion rate and standing crop of nectar in the British native plant species Salvia pratensis , Stachys palustris , S. officinalis , Lythrum salicaria , Linaria vulgaris , the non-native Calendula officinalis , Petunia  ×  hybrida , Salvia splendens , and the possibly introduced Saponaria officinalis . We also compared single with double variants of Lotus corniculatus , Saponaria officinalis , Petunia  ×  hybrida and Calendula officinalis .