Cultivation

Cut flower suitability — Rudbeckia hirta, coneflower

Rudbeckia hirta L.

Rudbeckia hirta is a 'cut-and-come-again' crop whose vase life depends on the flower opening stage and strict water hygiene due to high risk of bacterial contamination.

In the reference 8 varieties crop Black-eyed Susan, where this is mentioned in the description.

To obtain high-quality cut material, Rudbeckia should be harvested after the inflorescences have fully opened and the stems have become firm and rigid. Readiness is verified by the shake test: the stem should remain stable when shaken. Harvesting immature buds too early results in rapid wilting.

The stems of this crop are covered in stiff hairs, which contributes to rapid bacterial growth in the water and blockage of the xylem vessels. To extend vase life up to 5–10 days, strict control of water cleanliness is required. Regular harvesting of spent blooms stimulates the formation of new buds throughout the season.

Stem quality and length are directly dependent on the photoperiod: Rudbeckia hirta is an obligate long-day crop. Under insufficient light conditions, the plant forms a rosette without producing a flower stalk, while excess light (over 16 hours) induces excessive stem elongation, reducing their structural strength.

General information about the subject — on the page Suitability for cutting.

Sources8

Varieties of Black-eyed Susan mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.