Centaurea was once a common farmland weed, but breeding has turned it into a colorful annual for flowerbed or cutting. The tall group of Centaurea Cyanus reaches 2. 5 feet to 3 feet. The blue Diadem is a good choice with its large deep blue flowers. Dwarf group grows only about one foot and the best one to pick is the Polka dot. The blue varieties are grown for use in arrangements.
Water regularly in dry weather.
Sow seeds in September or April where they are to flower.
Centaurea are best in cool districts and will do well in almost any climate, provided the soil is on the alkaline side.
Dead head regularly.
Stake tall varieties.
Centaurea thrives in sun or partial shade. Flowers in June-September. Keep watch for mildew and aphids to which Centaurea are particularly prone.
Any well drained garden soil.
Most plant cells look like little boxes full of green disks. The disks are called chloroplasts. Other organelles inside a plant cell include a nucleus (where the DNA is kept), a large central vacuole (where water and other materials are stored) and a complex internal skeleton or cytoskeleton made of various proteins.