Perovskia is neither Russian nor sage; rather, it is native to southwestern and central Asia, Afghanistan to Tibet. It is a member of the Lamiaceae (mint) family, as are the true sages in the genus Salvia. It was probably first called sage because its crushed foliage smells sage-like.
In the Garden
Russian sage foliage is gray-green, with small, finely toothed leaf edges and pale green stems that age quite attractively to silver-white in winter.
- Foliage is pleasingly but pungently scented when crushed or brushed against.
- Tall, long-blooming, lavender-blue flower spikes lend a cool, airy cloud of color to the garden mid- to late summer.
- Even in winter, groups of the white bare stems stand out as an attractive and prominent feature.
- Its loose, open habit makes this perennial an effective filler in the back of a border or above low-growing plants.
- Perovskia combines well with ornamental grasses and white or yellow-flowered perennials along with red or orange blooms.
- Plant Russian sage ranked in a row as a wide hedge, as 1 or 2 individuals, or in broad swaths to magnify its presence.
- Especially when in full flower, this plant makes an impressive site when featured apart from neighboring plants and above a layer of attractive mulch.
- Wide sweeps of blossoming spikes attract hordes of bees and butterflies, but deer do not bother this plant.
- Hardy to the lowest temperatures we see in Sonoma County, Perovskia also seems to be fairly resistant to leaf pests and most diseases.
Growth Habits
In cultivation since the mid-1800's, Perovskia is botanically a subshrub with woody lower stems and taller soft herbaceous tissue where flowers appear.
- It grows 3-5 ft. tall, spreads fairly fast and becomes robust with more rather than less irrigation.
- It is a bit of a rampant spreader by underground rhizomes after several years.
- Wait until after the last frost in spring before pruning Perovskia, then cut back hard to basal shoots about 6 in. above the ground, always cutting just above pale green buds.
- New growth emerging on low, woody stems encourages a denser habit.
- If plants are not pruned hard enough, growth can become lax and droopy, particularly when young.
- Several cultivars bring a range of growth habits to the garden.
- 'Longin' is a bit better-behaved than the plain species and has a more upright, formal growth habit.
- 'Blue Spires' grows to about 4 ft. with foot-long flower-heads from mid-summer into fall.
- 'Little Spire' is more compact to 2 ft. tall.
- 'Filigran,' the sturdiest and most upright of any Perovskia, is 2-3 ft. tall with silvery, fine, lacy or filigreed leaves, as the cultivar name suggests.
Water and Soil
Perovskia prefers relatively poor, well-drained soil, full sun, and little water.
- Fertile soil will boost leggy growth that requires support for tall stems or plants will flop and become untidy.
- It is quite drought tolerant and suffers when over-watered, but it must be irrigated regularly during the first growing season to establish a deep, extensive root system.
- Good drainage and aeration enable it to survive through wet winters and prevent root rot in saturated soil.
September 2023