Centaurea macrocephala

Centaurea macrocephala, also known as giant knapweed, resembles a massive dandelion, with its huge, tousled, golden-yellow head emerging from a rosette of very large dark green leaves. This hardy perennial forms an imposing and decorative upright clump, ideal for adding verticality to sunny borders. Easy to grow in any light or gravelly soil, even poor and chalky.

Giant knapweed belongs to the Asteraceae family and originates from subalpine fields in Armenia and neighbouring regions of Turkey. It is an herbaceous, deciduous perennial with a taproot, forming a basal rosette that can reach up to 80cm (32in) wide, from which emerge flowering stems that reach a minimum of 1.2m (4ft). The plant then forms a lush, erect clump with numerous leafy stems that extend to their tips. The nectar-rich and honey-bearing flowering occurs from July to September, in the form of enormous golden-yellow heads that are 9cm (4in) wide, with a base composed of shiny brown bracts shaped like clubs. The stems are uniflorous. The rosette leaves are entire, medium green, narrow and ovate, measuring about 25cm (10in) in length. The cauline leaves are positioned all the way up the flowering stem. They are slightly smaller, lanceolate, and undulate, and bear the same green colour. Both leaves and stems are tomentose.

Centaurea macrocephala is a truly ornamental plant, perfect for the back of sunny borders. Its undemanding nature means it can be planted with tall blue thistles like Onopordum acanthium, Cynara cardunculus, and Eryngium giganteum in average and dry soils. It can also be paired with other tall and slightly wild plants such as Verbascum olympicum, Ligularia stenocephala, Cynara cardunculus, Verbena bonariensis, Campanula lactiflora, and Ferula communis for a picturesque effect. It can also be planted in a large rockery. It's worth noting that its flowers hold up well in bouquets and can be used in dried arrangements.