If you want a splash of blue near the front of a border, then low-growing herbaceous perennial Veronica austriaca subsp. teucrium 'Royal Blue' AGM is perfect.
Its common name, ‘saw-leaved speedwell’, gives a lot of clues about its appearance. The clear blue flowers are held in short spikes above the toothed leaves.
Veronica 'Royal Blue' forms a bushy plant about 45cm (18in) in height, but it is advisable to cut it back after flowering to encourage a compact habit and good flowering the following year; it may even bloom again the same year.
It prefers a sunny position, although it will tolerate some shade. Grow in a sheltered position in a loamy, moderately-fertile, moist but well-drained soil (acid, alkaline or neutral). To ensure these conditions for this and all our herbaceous perennials we mulch our borders in early spring with a composted mix of chipped bark and animal manure.
'Royal Blue' is best grown in an informal planting scheme as we do here at Rosemoor, where you can find it at the front of the border in the Spiral Garden and the West Country Town Garden. It is generally pest free, but watch out for mildew.
For harmony in the border, plant with other blues; for example, hardy geraniums (deep blue Geranium 'Brookside' AGM and lighter Geranium Rozanne 'Gerwat' AGM are good ones to try) and silver foliage plants including Artemisia. Purple foliage such as Heuchera villosa 'Palace Purple' will go well and orange geums - for example, ‘Dolly North’ and ‘Totally Tangerine’ - will add a bit of ‘zing’. The magenta flowers of Erodium manescavii or Geranium sanguineum will give added depth in colour.
This plant is available from Rosemoor Plant Centre along with a range of plants that will look good planted alongside. The blue of this Veronica will combine with almost anything you fancy and its usefulness as a front-of-border plant in a sunny position is hard to beat.