Sandy everlasting, Helichrysum arenarium, a perennial belonging to Asteraceae family, is a source of valuable herbal material and therefore is under partial protection in Poland. It grows in sunny places on sandy soils, in abandoned fields, along roadsides and in dry forests and thickets, where it enters into symbiosis with arbuscular mycorrhizal fungi. The studies on the biology, ecology and cultivation of sandy everlasting have been vigorously pursued since 2003. The aim of this work was assessing the influence of root colonisation by mycorrhizal fungi on the growth and development of H. arenarium cultivated on clayey soil. Two independent experiments (in the pots and in field) were performed. In the first one, under laboratory conditions, the effect of inoculation of soil with arbuscular fungus Glomus intraradices on the biometric features of sandy everlasting seedlings was analyzed. The second experiment was designed to show the association of the root colonisation level with the biometric features of generative shoots grown in an open field. It was demonstrated that sandy clay is an appropriate medium for growing sandy everlasting, enabling a proper development of seedlings and ensuring high inflorescence yield. The amendment of soil with inoculum resulted in a significant decrease in the mass of vegetative and generative shoot parts and made the cultivation more expensive. The inflorescence yield (Inflorescentia Helichrysi) obtained from inoculated plots was lower by 36%.