Centaurea nigra ssp. rivularis - Garden cornflower

continental : They prefer locations where they can receive direct sunlight for at least few hours.
Normally these are very rustic plants, therefore can be grown in the garden all year long.

alpine : It is advisable to place these plants in a very bright location, exposed to direct sunlight.
The Centaurea nigra ssp. rivularis are rustic plants, they can tolerate without any problem also intense frosts; during particularly rigid winters cover the aerial part with frost cloth.

mediterranean : Place these plants in a very bright location, possibly exposed to direct sunlight.
They are very rustic plants, that do not suffer from cold.

Fertilization Centaurea nigra ssp. rivularis : Fertilize our annual plants adding a slow-release granular fertilizer to the planting soil; later on give it regularly every 10-15 days, using a fertilizer to be added to normal waterings.

continental : It is advisable to water regularly, specially during the hottest months of the year, avoiding to leave the soil dry for very long periods; the Centaurea nigra ssp. rivularis like slightly humid substrates all year long. In autumn and winter you can avoid watering, or intervene during warmest days only.

alpine : Try to keep a mostly humid soil, remember to water generously specially in summer; we can avoid watering during the cold season, or decrease waterings, intervening only in case of long duration drought.

mediterranean : Water the Centaurea nigra ssp. rivularis rather regularly from March to October, always allowing the soil to dry out well between two waterings. Avoid water excesses or stagnating water; during the cold season waterings can be decreased or suspended.