Normally when gardeners talk of companion planting it will have some scientific basis to do with pest control or maximising crop yields.
You know, planting Rosemary with cabbage because Rosemary repels cabbage flies or marigolds with Aubergine as marigolds deter nematodes.
Here, however, we are celebrating nothing so practical, rather one of the most stunning, aesthetically pleasing combinations two plants can offer. And it is not a pairing that the natural world could provide unaided by human imagination and ingenuity – Perovskia Blue Spire comes to us from the Himalayas, Lavender from the Middle East.
On the practical front, both plants need full sun and good drainage, beyond that, they are equally unfussy. This compatibility even extends to their respective fragrances which complement each other so perfectly and subtly that it’s hard to put it down to chance. The scent of Perovskia Blue Spire’s wonderfully aromatic leaves is even reminiscent of Lavender.
The two have contrasting and complimentary silver-grey foliage and when the leaves of Perovskia Blue Spire drop in winter, the remaining grey to white stems provide a new and equally stimulating backdrop for Lavender.
It is in summer, though, that we can enjoy the full glory the two have to offer when both are in flower. As the name suggests, Perovskia Blue Spire has magnificent violet-blue, tubular flowers covering up to 30cm of its stem.
The swaying, cloudlike effect they produce is simply wonderful and, again, a perfect foil to Lavender’s more robust, structured flower stems.
The colour contrast is equally effective (even with a white flowered Lavender like Alba) and truly spectacular with the more traditionally coloured Lavender varieties from Dwarf Blue to Grosso; Hidcote to Imperial Gem; Richard Gray to Twickle Purple.
Finally, then, how best to bring the two together? Well, if you are fortunate to have a large garden, then don’t skimp – a sweeping display, Perovskia Blue Spire at the back, Lavender at the front, will justify every inch.
And if your garden is more modest, the same still applies – whatever space you can give these two will be rewarded whether you plant a clump of Perovskia Blue Spire ringed by Lavender (particularly effective in an island bed) or in a row behind.
And even if your garden is small, you can (should) still find space for both – even a couple of each will provide a glorious focus and you can even achieve this in a large container or raised bed.
‘A marriage made in Heaven’ may be a cliché, but plant these two and you’ll understand how it came about.