Agastache 'Liquorice Blue' Seeds

Agastache rugosa is a Hardy Perennial (H4), though it's often treated as short-lived in the UK—not because it won't survive winters, but because it gives so much energy to flowering that many gardeners prefer to grow it fresh every few years for the most spectacular display.

Also known as "Korean Mint" or "Giant Hyssop," it originates from East Asia and Korea. It's incredibly vigorous and will bloom just a few months after sowing, often producing its first flower spikes by July from an early spring sowing. The essential oils in the leaves are intensely fragrant—on a hot day, you can smell the liquorice scent wafting through the air without even touching the plant.

Wildlife Champion: This plant is consistently rated as one of the single best perennials for pollinators. From midsummer through to the first frosts, you'll see bumblebees, honeybees, hoverflies, and butterflies working the flowers from dawn until dusk. It's listed on the RHS Plants for Pollinators list for good reason!

Agastache is wonderfully easy to grow, but it does have one golden rule: excellent drainage is essential. It hates sitting in wet soil during winter, when prolonged dampness is far more damaging than cold.

How to Sow:
Sow indoors from February to April. Surface sow onto moist, well-draining seed compost and don't cover the seeds—they need light to germinate. Keep them warm (around 18-20°C) and you should see seedlings in just 7-14 days. Germination is usually wonderfully quick and reliable.

Where to Plant:
Plant out after the last frost in late May or early June. They absolutely must have full sun and free-draining soil. If you have heavy clay, grow them in raised beds or containers, or add plenty of grit to the planting hole. They're highly drought-tolerant once established and actually perform better in leaner soils—over-rich conditions can make them floppy.

Ongoing Care:
Water regularly until established, then leave them to it. They're incredibly low-maintenance. Deadheading is optional—while it encourages more blooms, the seed heads look beautiful standing through winter (like dark architectural skeletons) and provide valuable food for goldfinches.

Overwintering:
In well-drained soil, Agastache can survive UK winters down to -15°C. Mulch lightly in autumn and consider cutting back to 15cm in late autumn to prevent water pooling in the crown.

The vertical blue spikes of Agastache create gorgeous combinations when contrasted with complementary shapes and warm colours:

• 🌼 Rudbeckia 'Marmalade': The colour clash here is simply stunning. The deep golden-yellow of Rudbeckia provides a vibrant, sunny contrast to the violet-blue of Agastache. Both flower generously from July through to October, creating a classic "hot and cool" prairie-style combination that pollinators absolutely adore.
• 🌸 Echinacea (Coneflower): The large, flat, daisy-like heads of Echinacea sit beautifully alongside the tall, thin vertical candles of the Agastache. This is a classic prairie planting combination beloved by garden designers—the textural contrast is simply perfect, and both plants provide exceptional winter interest with their seed heads.

Sow indoors in spring for flowers from July to October the same year.