KEEP an eye out for young plants of the excellent Verbena bonariensis, which starts flowering in June on stately stems that are usually taller than me. In the last few years, this extraordinary plant seems to have taken over every serious border scheme, though that could be partly because it won' stop putting itself around by self-seeding profusely, often in the most fetching places where it is good at combining itself gracefully with other plants.

In one part of the garden it has seeded itself in pea gravel in company with some shivering Stipa tenuissima and blue cranesbill, to great effect. It's an altogether good plant that rarely puts a foot wrong, though it does have a mild tendency to topple over in the wrong place, which can be rectified easily by discreet staking or tying. Beautiful planted en masse or with grasses, it's a transparent plant that allows you to see beyond it to the back of a border, so it doesn't matter if it's seeded near the front.

When young, seedlings are amenable to transplanting, but less so as they age. It has rough dark green leaves and wiry, angular, branching stems which can soar to a whopping six feet.

The lavender-blue flowers are luminous in sun, fragrant and actually tiny, though they grow in dense tufts, making strong heads of colour. They are produced generously from June until late autumn. A winner.