Helianthus
How do you plant your helianthi rhizomes?
Plant your helianthi, sold as Helianthus strumosus, using healthy tuberous rhizomes. This is the perennial vegetable, not a planting method for every sunflower. Plant in late winter or spring when the soil is workable, adjusting to severe local frosts. The rhizomes are hardy, while young shoots need closer attention.
Choose deep, well-drained soil that retains some moisture, in sun or light partial shade. Allow for the plant's height and the shade it may cast on neighbouring vegetables. Loosen a generous area, remove perennial weeds and add mature compost if necessary. Plant the rhizomes about ten to fifteen centimetres deep, with fifty to sixty centimetres between them and eighty centimetres to one metre between rows.
Use whole rhizomes or pieces carrying a viable bud. Cover them, firm lightly and water if the soil is dry. Mark the positions and weed carefully while growth begins. Maintain moisture without standing water. Choose a site you can monitor from the start: overlooked rhizome fragments can regrow and expand the clump over subsequent years.
How do you cut back Helianthus strumosus?
When and how do you harvest helianthi?
