Rudbeckias or coneflowers, natives of North American vast prairies, arrived in Europe long time ago with a very ambitious and secret plan to colonise the Old World (of course, it is my interpretation). Being very prolific responded with great generosity to hospitable new lands and spread quickly within gardens they were planted. And not only within. Confinements of all sorts are not for such energetic plants like rudbeckias whose ruler-according to Zodiac readings -is the sun and fire their element. They can dominate every territory showing uncompromising determination while seducing everybody with ornamental leaves and graceful flower heads.
The perennial species Rudbeckia laciniata cv. Goldball forms tall (2m, 7 ft) clumps of upright leafy stems which now, in August, terminate in numerous ball-like yellow flower heads. A great view, I must admit, but not everlasting. The stems are quite prone to become warped or break if the wind is strong or heavy rainfall occurs. Timely support with bamboo canes is much needed. This cultivar is one of the most vigorous and if left unattended, it will quickly conquer a large territory of the garden smothering the neighbouring plants without mercy.
The original type forms single flower heads with a few petals pointing out and down. It does not spread by underground root offspring like the previous one, but have worked out a better solution: seeds. And are they vital! Anyone who has this really beautiful plant in the garden knows what I mean. I advise caution while spring works in the garden. If you see young plants of this rudbeckia do not think twice before digging them out.
Rudbeckia fulgida var. sullivantii is a quite moderate black-eyed-susan, especially its new cultivars. They grow to reasonable heights (ca. 1 m/3 ft) and their stems are sturdy enough to withstand all summer dynamic weather conditions. A great choice for every summer blooming garden. The black centres (in reality flowers) are ornamental even after the yellow petals disappear. We can leave them in the garden or cut and arrange a dry interior decoration.