Best of the bunch
These useful upright perennials look fabulous as repeat planting in borders, don’t need staking and are particularly good in cottage gardens.
Producing spikes of blue flowers ranging from light lilac to deep purple, they have a long flowering season and also attract bees and butterflies.
They will do well in reasonable garden soils, growing in light shade and sunny spots and may bloom into September if you remove the flower spikes as soon as they fade.
They contrast well with orange geums or yellow flowered achilleas. Good varieties include S. x sylvestris ‘May Night’ and S. uliginos.