How to grow Hesperis
From the Greek hesperos, evening, when the flowers of some species become fragrant (Cruciferae). A genus of hardy plants including biennial and perennial species. Similar in form to Matthiola and Cheiranthus, and native to Europe and W. and N. Asia.
Perennial species cultivated H. matronalis, sweet rocket, dame's violet, dame's rocket, 2-3 feet, flowers fragrant in evenings, variable between white and lilac, May to July; vars. candissima, 15 inches, pure white, purpurea, purple. Double forms have appeared from time to time but are rare in cultivation.
Biennial H. tristis, 1-2 feet, flowers ranging from white through brick red to purple, fragrant at night, summer. H. violacea, 6-12 inches, violet flowers, June.
Cultivation H. matronalis and its forms will thrive in an ordinary soil with a regular moisture supply, in full sun. Plant in autumn or spring. Plants do best if fed by mulching with well-rotted manure in May. Remove spent flower stalks in autumn. Double varieties, when obtainable, benefit from occasional extra feeding with liquid manure during summer, and replanting in alternate years. Single varieties can be raised from seed sown inch deep in a warm spot outside in April. Transplant seedlings in June or July. Double varieties can be perpetuated only by cuttings, 3 inches long, taken from July to September, and inserted in a shaded position outdoors. Later cuttings, taken in September or October, require glass protection. Transplant in March. Established plants may be divided in autumn or spring. Biennial species are raised from seed sown direct in sunny flowering positions in July. Thin seedlings to 9 inches apart. H. violacea can be established on stone walls where a roothold permits.