When to plant Red bistort 'Firetail'?

Persicaria amplexicaulis 'Firetail' thrives in full sun or partial shade, making it adaptable to a range of garden positions. It performs best in moisture-retentive loam or clay soil, so avoid dry, sandy spots. Before planting, dig over the soil to a spade's depth and incorporate plenty of organic matter—well-rotted compost or manure—to improve structure and water retention, especially if your soil is on the lighter side. Plant 'Firetail' in March, April or May for spring planting, or in September and October for autumn planting. Both windows work well; autumn planting allows roots to establish over winter, while spring planting suits colder or wetter gardens where drainage may be an issue in winter. Dig a hole roughly twice the width of the root ball and the same depth. Position the plant so the crown sits level with the surrounding soil—planting too deep can lead to rot. Space plants 60 cm apart; 'Firetail' will spread to 60–90 cm over time and benefits from room to develop its clump-forming habit without crowding neighbours. After planting, firm the soil gently around the roots to eliminate air pockets, then water thoroughly to settle the plant in. Apply a 5 cm layer of organic mulch such as garden compost or bark chips around the base, keeping it clear of the crown itself. This conserves moisture, suppresses weeds, and feeds the soil as it breaks down. Water regularly during the first growing season until the plant is fully established, especially in dry spells.