Salvia japonica: is a small herbaceous perennial from Asia 10-20cmH with pale blue flowers in spring and summer.
Salvia japonica is a small winter dormant clumping Salvia .
Flowers: are small, pale blue, semi tubular with the hood jutting out, the stigma exerted further out,while the bottom middle lobe is reflexed down to open up the throat to allow bees and insects to enter the corolla. The two side lobes stand up to enclose the landing platform for insects.
Flowering stems appear in early summer, lasting till early autumn.
Flowers appear in small whorls of 4 flowers, evenly positioned along a shiny green stem. Stems are long, approx10-15cm long, held above the foliage to attract passing insects.
Calyces: are a bright green, lobes being sparsely ribbed, bluntly pointed and shiny. These remain on the stem after the flowers have dropped, drying nicely if carrying seed.
Leaves: are a dark midgreen and pinnately lobed with 5 lobes, the central lobe being largest. Leaves are shiny above, well veined with soft crenations around the margins. Each leaf is approx 10-15cm long, forming a nice compact neat basal clump, with the flowers arising from the centre of the clump.
As Salvia japonica is such a small clumping plant, it makes an ideal plant to be grown in a pot or in a rockery.
Place pots under deciduous trees or open evergreen trees where the plant can enjoy dappled sun or semi shade. If growing the plants in the ground, then they make a lovely border along a path or around a pond etc..
Plant with other very small shrubs and perennials that enjoy the same dappled sunny position. plants from a woodland situation would be ideal companions.
Although winter dormant, S. japonica should have well draining soil with enough compost to keep the soil moist but not wet during the hot summer months.
At the end of autumn, when the plant will be preparing to “go down” for winter, clean away spent flower stems, old leaves, but lightly mulch the crown, to keep it warm over the cold winter months. Mulch can be gravel or grit to stop snails from feasting on new shoots as they emerge in spring.
In spring when the new shoots appear, feed and mulch well with a sugar cane type mulch to keep the root area cool during the hot dry summer months.
Propagation: can be either small basal cuttings taken in spring and late summer from new growth, division of the clump or by seed sown in early spring.