Veronicastrum (Veronicastrum virginicum) is a hardy, herbaceous perennial that has been in garden cultivation for hundreds of years but has only gained popularity in the last couple of decades, thanks to a revival of naturalistic planting styles. Its vertical branching stems are excellent for architectural impact in sunny borders, and its long tapering blooms, made up of many tiny flowers, are a magnet for insects.
Veronicastrum forms neat clumps and is not invasive, with tall, slender stems emerging from lance-shaped, green leaves. The flowers of veronicastrum come in a range of colours from soft pink, lilac and white through to mauve and darker pink. Colour and interest last for many weeks in summer as the tiny flowers open gradually from the base to tip of each bloom. Height range varies according to variety – the shortest are around 1m high, with the tallest up to 1.5m.
How to grow veronicastrum
Plant veronicastrum in full sun or light shade in fertile, moisture-retentive soil. Once established, plants need very little care apart from an annual mulch in late winter. Leave dead stems standing through autumn and winter until they lose their structure. Cut back to the ground before spring.
Where to grow veronicastrum
Site in sun for the best flowers, although plants do still flower reasonably well in light shade. Plant in borders, in good soil. Veronicastrum looks best in groups or repeat-planted, in a mixed border or with grasses and perennials in a naturalistic-style planting scheme.
How to plant veronicastrum
Ideally grow in soil that is fertile and moisture-retentive, although not wet or waterlogged ground. Improve dry soils with plenty of organic matter to retain moisture. Plant in autumn, during mild spells in winter, or in early spring. Only plant veronicastrum in summer if kept watered for the rest of the growing season.
How to care for veronicastrum
Once established, veronicastrum needs little care apart from cutting back dead growth, and ideally mulching with garden compost or an organic mulch in late winter. Usually plants are self-supporting, although may need staking in wet years that encourage lush growth, or in exposed sites. Either use grow-through supports put in place during spring that become hidden by plant growth, surround each plant with canes and string, or insert twiggy hazel stems in the ground around the clump.
How to prune veronicastrum
Cut back dead stems to ground level, before the emergence of new growth in spring.
How to propagate veronicastrum
Unlike most herbaceous perennials, veronicastrum does not benefit from division, which can damage the plants. The best method of propagation is by taking cuttings from non-flowering side shoots in summer. Once rooted, grow these on in individual pots until well grown, to plant out the following year.
Pests and diseases
Veronicastrum is usually free of pests and diseases.
Advice on buying veronicastrum
- Veronicastrum is available from nurseries and garden centres, sometimes in a choice of pot sizes
- A range of varieties can be found from online suppliers, usually in 9cm pots though occasionally in larger 2l pots
- Do not confuse veronicastrum with veronica, which looks similar in flower but lacks the habit and stature of veronicastrum
Where to buy veronicastrum
Veronicastrum varieties to try
Veronicastrum virginicum ‘Album’ – pure white flowers. Height x Spread: 1.2m x 75cm
Veronicastrum virginicum ‘Cupid’ – deep lavender-blue flowers. H x S: 1.2m x 50cm
Veronicastrum virginicum ‘Fascination’ – mauve to lavender-blue flowers. H x S: 1.5m x 45cm
Veronicastrum virginicum ‘Lavendelturm’ – pale lavender flowers. H x S: 1.5m x 45cm
