Greater Knapweed Seeds (Centaurea scabiosa)

A bold and beautiful perennial wildflower with large, thistle-like purple blooms that bring height, colour, and pollinator interest to meadows and grassland plantings. A long-standing favourite of butterflies and bees, it flowers through high summer when nectar is most in demand.

Key Features:

• A haven for numerous pollinators
• Robust and long-lived perennial, thriving in low-fertility soils
• Tall, upright growth, adding height and structure to wildflower patches
• Approx. 130 seeds per 1g

Greater Knapweed (Centaurea scabiosa) is a showy and statuesque perennial with branching stems and generous flower heads that resemble soft thistles, though without the prickles. Each bloom is made up of fine, feathery outer petals surrounding a tight, central tuft, creating a bold yet intricate flower that’s irresistible to insects.

This is a taller wildflower, typically reaching between 60–100 cm, though it remains upright and well-mannered in most settings. The foliage forms a low-growing, slightly toothed rosette at the base, with flowering stems rising above from the second year onward.

Flowering begins in mid to late summer and continues well into early autumn, helping to bridge the gap between early wildflowers and the end of the growing season. Its generous nectar production makes it one of the most popular species among pollinators, particularly butterflies, such as the Marbled White and Meadow Brown, but bees, hoverflies and beetles also visit it regularly.

Greater Knapweed thrives in full sun and prefers free-draining soils. It’s especially at home in chalky or sandy conditions, but also performs well on loam with good drainage. It’s well-suited to naturalistic planting schemes and performs best where competition is not too intense, giving it the space to stretch and flower to its full potential.

Sow Greater Knapweed either in early spring (March to May) or autumn (August to October). Like many perennials, it can benefit from a period of winter cold to help break seed dormancy, so autumn sowing often leads to stronger spring emergence.

Prepare a weed-free, well-raked seedbed with a fine, crumbly texture. Scatter the seed evenly and press gently into the surface, covering lightly with a thin layer of soil or compost.

In its first year, the plant will usually form a leafy rosette while it focuses on establishing its deep taproot. Flowering typically begins from the second year onwards, with each season bringing taller stems and more blooms.

Once established, Greater Knapweed is low maintenance and thrives in nutrient-poor soils. After flowering, seed heads can be left for birds or cut back if tidiness is preferred, though allowing some to remain can support natural self-seeding and wildlife.

For garden applications direct sow at 1g/m2. For overseeding existing meadow planting or for new sowings on larger areas sow at a maximum of 2g/m2.

Greater Knapweed is a standout addition to wildflower meadows, grassy verges, field margins, and wildlife-friendly gardens. Its large, nectar-rich flowers are a magnet for butterflies, and the tall stems provide a useful landing platform for many insects. Later in the year, seed heads offer food for finches and other birds, while the plant's deep roots help anchor soil and support long-term biodiversity.

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Garden lawn seed, wildflower seeds, and wildflower seed mixtures are typically dispatched within 1 to 3 working days.

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Q1: Is Greater Knapweed suitable for smaller gardens?

A: Yes, although it’s a taller species, it behaves well and works beautifully in borders, prairie-style planting, or mixed wildflower beds. Its height adds drama without overwhelming.

Q2: How soon will it flower after sowing?

A: In most cases, flowering begins in the plant’s second year, as it puts energy into root development in the first. Once established, it flowers reliably each summer.

Q3: Does it need rich soil or feeding?

A: Not at all, it thrives in low to moderately fertile soils and actually prefers conditions without high nutrient levels. Overly rich soil can reduce flowering and cause leggy growth.

Q4: Will it spread aggressively?

A: No, Greater Knapweed is a well-behaved perennial. It may gently self-seed if allowed, but it doesn’t spread invasively or smother other plants in a mixed meadow.