What is a biennial plant?
Q: What is a biennial plant?
A: A biennial plant is a flowering plant that takes two years to complete its lifecycle. In the first year, the plant grows leaves, stems, and roots (vegetative structures); then it enters a period of dormancy over the colder months. The next spring/summer the stem of the biennial plant becomes much longer and it flowers, produces fruits and seeds before it finally dies.
Q: How many biennials are there compared to other plants?
A: There are far fewer biennials than either perennials or annuals.
Q: Are there any conditions that can cause a biennial to complete its lifecycle in less than two years?
A: Yes, under extreme climatic conditions such as cold temperatures, a biennial may complete its lifecycle in only 3 or 4 months instead of 2 years. This is quite common in vegetable or flower seedlings that were exposed to cold conditions before they were planted in the ground.
Q: Can gibberellin be used to induce flowering in some biennials?
A: Yes, flowering can be induced in some biennials by application of the plant hormone gibberellin; however this is rarely done commercially.
Q: Does a gardener's perspective affect how long a plant lives for?
A: Yes, from a gardener's perspective, a plant's status as annual, biennial or perennial often varies based on location or purpose. Biennials grown for flowers, fruits or seeds need to be grown for two years while those grown for edible leaves or roots are treated as annuals and usually only last one year.
Q: What examples of plants are considered true biennials?
A: Examples of true biennials include parsley, Lunaria silverbeet sweet William colic weed and carrot; however pansies are often treated as an annual even though they're technically classified as being biennial plants.
Q: Are there any cultivars of certain normally-biennial plants that will flower during their first year from seed?
A:Yes - Plant breeders have produced annual cultivars of several normally-biennial plants that will flower during their first year from seed; examples include foxglove stock and hollyhock.
