How to plant cosmoses (Asteraceae)
Cosmoses (Asteraceae) produce wonderful chocolate-scented, reddish-brown saucer-shaped flowers on tall stems. Native to Mexico, these herbaceous jewels look especially great planted with greyish-blue/reddish grasses and perennial plants such as achilleas, echinaceas and heleniums; for more visual impact, try mixing in red or yellow crocosmias.
Plant in moderately fertile, well-drained moist soil in full sun. Dead-head regularly to prolong flowering. Provide mulch in autumn and lift and store tubers in barely moist peat in frost-prone areas.
Cosmoses are supplied in 9 cm pots. Always unpack on arrival and store in a cool place until ready to plant.
Potential problems, pests and diseases:
- Aphids: these sap-eating insects can weaken plants and spread viruses. Whenever possible, pick off by hand using gloves.
- Snails and slugs: these pests enjoy munching on young shoots, stems, leaves and flowers. Watch out for damage!
- Botrytis/grey mould: this fungal disease usually caused by excessive moisture, warm temperatures and poor air circulation can initially be seen as brown spots/grey mould on the leaves and stems. If you spot any signs of this disease, immediately remove the affected bulbs/plants and destroy. Botrytis is an airborne virus and can spread rapidly in the breeze so do not compost any infected material.