Blue Spires

Russian Sage – Perovskia atriplicifolia Little Spire

I’m quoting from Graham Stuart Thomas’ book, Perennial Garden Plants and I think he is a fan.

Ardent sun-lovers for well-drained soil. In shade they will flower but tend to sprawl. Though truly shrubs they are best cut to the ground every spring to encourage strong shoots and good flowers.

Perovskia atriplicifolia hails from Afghanistan to Tibet. A beautiful plant of the sage family and thus aromatic. The base sends up grey-white stems and aromatic coarsely-toothed leaves, gee-white beneath, supporting elegant bright lavender-blue flowers, like lavender, but in open spires. A lovely combination of colours and it is in flower for many weeks. The grey stems are attractive in winter. Full sun, good drainage, ordinary soil. This grows and flowers remarkably well at Wisley, Surrey, on top of a retaining wall. Beautiful with Anemone tomentosa.

‘… the plant is worth a place in the choicest garden for its graceful habit and long season of beauty.’ – William Robinson The English Flower Garden

Helen Yemm, writing in The Telegraph in 2003, is also a fan.

How to grow: Perovskia

Watch out, here comes the last and tallest member of the sun-lovers.

By Helen Yemm
26 Jul 2003
For those of us who love the outdoor drama of flowering aromatics, late July and August can be a disappointing month. The cistuses and sages have finished, lavenders are passing their peak and catmint, cut down around mid-July, is resting. But thankfully, on to centre stage comes perovskia, the last and tallest member of the sun-lovers. A brilliant swathe of Perovskia atriplicifolia in full flower in late summer can give a flagging garden a wonderful lift.
Commonly known as Russian sage, perovskia was named after the Russian count who first introduced it to Western gardens about 100 years ago. But this late summer/early autumn performer, a member of the Labiatae family, has its origins further east in the arid, rocky soil and wide open spaces of Afghanistan and the Himalayas.
Perovskia is a sub-shrub that grows annually from a woody base. The most commonly encountered form is Perovskia atriplicifolia ‘Blue Spire’ which each year puts out 3ft to 4ft tall erect silver stems clothed in ovate, deeply cut and lobed greyish leaves. At the end of the summer its stems terminate in long panicles of tiny, soft-violet tubular flowers. The effect is of a bluish haze hovering above the border, which is particularly effective among the longer shadows and in evening light.
An added bonus is that the leaves of perovskia are strongly aromatic when brushed or crushed and smell of both sage and lavender. The stems are deciduous and, with a little grooming and adjustment in late autumn, have a slender, upright, bleached presence in the garden that can last throughout winter.
‘Blue Spire’ is a real sun-worshipper, best planted in small groups to make a big impact. Its slim growth can be difficult to accommodate in smaller planting schemes. ‘Little Spire’, which was introduced fairly recently, grows to about 2ft and is suitable for gardens with less space. All perovskias need good drainage, are suitable for growing on shallow chalk and will adapt well to seaside conditions – provided they are grown in full sun.
Growing tips
In addition to a site with year-round sunshine, success with perovskia is all about pruning. In our climate the plants come late into leaf. They should be hard-pruned back to a little woody framework, no more than a few inches tall, just as they are beginning to leaf up. This will probably not be until mid-April.
If plants are pruned too early and too hard they may simply give up and die. If in doubt, it is best to wait until May when they will be in full growth. However, if perovskia is not pruned hard enough the growth can become lax and floppy, particularly when the plants are young. The untidy mess that ensues, while still attractive in a wild and woolly way, does not show the plant off to its best advantage and the flower spikes may get swamped by neighbouring plants.
In common with many aromatic, grey-leafed plants from more extreme climates than our own, perovskias actually seem to thrive on starvation rations and in parched places, putting on too much lush sappy growth if fed and watered, mulched and pampered along with the majority of our garden plants.
Another big advantage is that perovskia seems to be unattractive to leaf pests and not susceptible to disease. But beware of plants offered for sale too early in spring, already in leaf. They may have previously had the protection of the grower’s polytunnel and they may suffer a set-back from the cold if planted out too soon.
When planting, incorporate some grit into the soil to ensure perfect drainage, together with just a little bonemeal. Once the plants are established they will be generally trouble-free. Perovskia can be propagated from semi-hardwood cuttings taken in July.
Good companions
In planting schemes of grand proportions perovskia works well grouped en masse under big open skies, its silver shoots masking the fading leaves of underplanted spring tulips and alliums as summer advances, and eventually forming a shimmering blue haze when viewed from a distance.
For me, however, perovskia is at its best planted in a fairly tight group, hemmed in with other plants of slightly smaller stature that enjoy similar hot and sunny conditions in the garden – and it grows particularly well in gravel. In early summer its rising silver shoots are a magnificent foil to fellow blue-flowered, grey-leaved plants – Nepeta mussinii, dwarf lavenders, Cerinthe major, dainty calaminthas, eryngiums, purple sage and smokey-leafed Geranium pratense ‘Victor Reiter’. They look wonderful surrounded by clouds of self-seeded sky-blue Nigella damascena ‘Miss Jekyll’ and the upright heads of Allium nigrum. Later, as it achieves its full height and its hazy blue flowers develop, perovskia looks stunning among taller plants with more ethereal, late-summer presence: Verbena bonariensis, wafting grasses such as the Deschampsias that turn golden in late summer and the delicate smokey veil of lofty bronze fennel with its limey flowers.
Where to buy
Perovskia atriplicifolia ‘Blue Spire’ is quite commonly available from garden centres and nurseries, often sold in late spring and early summer already in leaf. The new smaller variety P. ‘Little Spire’ is subject to Plant Breeders Rights and may be more difficult to find.