Actually I don't know the difference. I have tried to now the difference between the two but I couldn't that is why I came to this website. Please I need to know because it is part of my agricultural science assignment.

  • @Rob "Google" isn't very useful advice, because almost everything on the web about "biannual plants" is wrong.
    – alephzero
    Feb 19 '19 at 18:15
  • Biannual is usually a misspelling of biennial - the term 'biannual' is not recognised in horticulture. Explanations given in the answer below are accurate in terms of defining a biennial plant.
    – Bamboo
    Feb 19 '19 at 19:55
  • Please see my comment responses below. It is explained accurately in the answer. Thank you.
    – user22542
    Feb 20 '19 at 1:31
  • @user22542 - I did read your answer and looked at the links you provided, and in fact referred to your answer in my comment - nonetheless,its still important to point out what I said in my comment., i.e., "biannual" is not a horticultural term and is a misspelling of biennial when used to refer to plants.
    – Bamboo
    Feb 20 '19 at 11:54
  • @Bamboo - Sorry for any over-response on my part. I was overwhelmed with the sudden flurry of comments and some of them were wrong. It was late.
    – user22542
    Feb 20 '19 at 12:05

Yes, plant terminology can be confusing. I hope these answer your questions.

A biennial plant is one that takes two years to complete it's life cycle (examples are given in the link below). "Biannual" is a general term not often used with plants, but it can be used to refer to a plant that does something two times (twice) each year (such as produce fruit or flower). Note: This word causes much of the confusion because it can have the same meaning as "biennial" for general English usages and purposes.

A perennial plant is one that lives for more than two years.

An annual plant is one that lives for only one year and must be grown from seed each year.

For the arguments sake, I added the Merriam-Webster dictionary "biannual" definition link below (read about the dual meaning) under "Did you know?" at the link.




  • 1
    Biannual means "once every two years", not twice a year - that would be semi-annual. The definition for "biennial" is, as Bamboo noted, correct.
    – Jurp
    Feb 20 '19 at 0:10
  • It means both in a general sense (not plant related sense). The term is not often used with plants. Please read the links. Possibly you are not understanding the freedictionary definitions. Both definitions are valid and correct in a general sense.
    – user22542
    Feb 20 '19 at 1:22
  • 1. and 2. are given "alternative words used" at the end for each definition, but BOTH 1. and 2.are valid definitions for "biannual".
    – user22542
    Feb 20 '19 at 1:27
  • I added the Merriam-Webster definition link also. Please look down the page at the "Did you know?" section.
    – user22542
    Feb 20 '19 at 2:23
  • @user22542: I think you are too much arguing with dictionaries. I never ever seen "biannual" on botanic term as definition 1. I really think it is always used as "biennial" (biennes as used by Linneus [in Latin]). The therm "twice a year" is usually used on the other case, because: less confusing, it is stronger (we talk about yield, so money), and more precise (less about 6 months, but more like around 3 to 4 months twice a year (with still a dormient period). Feb 20 '19 at 8:16

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.