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Wednesday - January 20, 2010

From: Beaumont, TX
Region: Southwest
Topic: Wildflowers
Title: Is Rudbeckia hirta annual, biennial... or what?
Answered by: Jackie OKeefe


The desciption for Rudbeckia hirta says it is biennial and blooms the second year then further down the page it says it is an annual, which is it? Will I see blooms the first or second year?


There are several factors which can determine a plant's longevity. Rudbeckia hirta (blackeyed Susan) thrives in a wide range of climates and soils. In the wild, having the adaptability to complete its life cycle in one season ensures survival in some environments, while being able to mature for a year before blooming promotes survival in other situations. Since weather conditions can vary considerably year-to-year, this adaptability is one of the qualities that makes  Rudbeckia hirta (blackeyed Susan) such a wide-ranging plant.

In Texas' warm climate, if your Rudbeckia hirta (blackeyed Susan) plant is sufficiently mature and gets enough rain/water it will almost certainly bloom this season. If it gets enough moisture through the heat of the summer, it will probably live for another year. If the spent flowers drop seeds, seedlings will sprout with the fall rains for a new generation of plants next year.

According to the  USDA's PDF Fact Sheet :

Adaptation and Distribution
Black-eyed Susan is naturalized in most of the states east of Kansas and the bordering areas of Canada. It is adapted throughout the Northeast on soils with a drainage classification range from well-drained to somewhat poorly drained. It will perform acceptably on droughty soils during years with average or above rainfall, but best growth is achieved on sandy, well drained sites. It is winter hardy in areas where low temperatures are between -30 ° and -20 °F.

Rudbeckia hirta

Rudbeckia hirta



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