Keeping cosmos short

Hello everybody, I inadvertedly bought regular Cosmos bipinnatus seeds, meaning to purchase dwarf Cosmos (I'm growing them in pots).

My question is, by breaking them can I make them flower at a shorter height? I doubt I have large enough pots for their full height.

Thank you!


  • LilylouiseLilylouise Posts: 1,013

    Hello Jovia - You could take the tops out which will hopefully make the plants bush out but they will probably still be a bit taller than the Sonata dwarf Cosmos.What size pot did you intend planting them in?

    Pam x

  • Well I have some choices, I could use 24 cm pots. Would that still be too small?


  • LilylouiseLilylouise Posts: 1,013

    I have grown a Sonata Cosmos in an 8" (20cm) terracotta pot  so I would have thought that 24cm would be o.k image The only thing you may have to do is give the plant a bit of support.

    Pam x

  • Great, so I can use these seeds. Thank you!

  • I had a similar query a while back. How big should the plant be before I pinch / take the tops off..... and how much should I take off?


  • Tropical SamTropical Sam Posts: 1,493

    Top them when you have 3 fully formed leaves - not seedling leaves. You will clearly see the difference. Keeping Cosmos in small pots will also keep them short, toping them will stop any flowers growing if you keep doing it - waste of time of geeting seed if you do so, unless you really like their leaves?

Sign In or Register to comment.