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Cosmos not flowering?

KmehKmeh Posts: 151
in Plants
Anyone else having this problem? Look healthy, plenty of foliage and about 70 cm tall. I gave them some tomato feed yesterday in the hope it might spur them onwards. They had little flowers when I was still gardening them off and now nothing! 

Any solutions?

Thank you
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Posts

  • FireFire Posts: 17,116
    Sometimes they can take eons to flower. Last year they waited and waited in statis until Oct; it drove me crazy. Do they have full sun? The thing to know is that if they flower late, you will probably get a great, full scale blow out show all the way to the frosts.
  • B3B3 Posts: 25,270
    Sometimes rich soil will slow them down but they'll get there in the end
    In London. Keen but lazy.
  • KmehKmeh Posts: 151
    I have very heavy clay. So rich in some respect I suppose. It's a nightmare to work with!  They get a large amount of sun - it's a south facing courtyard. 

    I did give them a good top chop in the early days because I planted them far too early and they got ultra leggy in their pots whilst too cold to plant out. Could this contribute.?
  • FireFire Posts: 17,116
    Yes
  • Pete.8Pete.8 Posts: 10,338
    I think soil is the main reason.
    I created a new bed a few years ago and manured it very well in the autumn.
    Next year the cosmos grew to 6ft+ before flowering. Rain and winds had already caused them to snap a lot of branches so some sprawled to abut 6ft across too, but they did flower well by about Oct.
    The following year wasn't so bad and better still the year after as the nutrients became depleted.
    From that experience I guess it's due to the soil being too rich, so they just keep growing. If they have plenty of food why not?
    Poorer soils keep them shorter and make them bloom earlier.
    I'm growing the dwarf ones this year to be on the safe side
    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • FireFire Posts: 17,116
    I loved my late flowering cosmos (yes, planted in manured soil). When the flowers did arrive, they shone in a garden bereft of other flowers by that point, and they were like trees - huge and covered in dark pink blooms, right into November. It was amazing. They make great cut flowers too. Maybe it's a plant to sow in succession. I would dearly love mine to self-seed, but they never do.
  • strelitzia32strelitzia32 Posts: 767
    @Pete.8 how are you finding the dwarf ones? I did the same as you and switched to them this year, I'm a bit disappointed. They're really really dwarf, I was expecting 2ft to 3ft of branching stems and lots of flowers, but almost all of them are tiny, maybe 18 inches max. Enough flowers for their size, but was expecting more...
  • Pete.8Pete.8 Posts: 10,338
    strelitzia32 said:
    @Pete.8 how are you finding the dwarf ones? I did the same as you and switched to them this year, I'm a bit disappointed. They're really really dwarf, I was expecting 2ft to 3ft of branching stems and lots of flowers, but almost all of them are tiny, maybe 18 inches max. Enough flowers for their size, but was expecting more...
    Yup - mine are the same.
    I sowed mixed seed too Cosmos Sonata Dwarf mixed. 
    The plants are flowering and every one so far is the same shade of pink.
    The plants are still small, but I have grown them before and they got to be about 3ft by late summer and were really sturdy plants - time will tell..
    Knowledge is knowing that a tomato is a fruit.
    Wisdom is not putting it in a fruit salad.
  • Matt_Matt_ Posts: 48
    I'm growing some Cosmos Bipinnatus Purity this year, all sown in early March but very staggered in flowering times. Three of them next to each other in the same bed; one has been in flower for almost two months, the next has been flowering for a couple of weeks with taller stems and larger flowers, and the third plant still isn't flowering. Not sure there's any wisdom to gain from this...
  • KiliKili Posts: 1,048
    Mine have been flowering for a month now they have gone absolutely bonkers, deheading everyday hundreds of flowers. Below is a small selection from an 18 foot bed. Its like that all the way along the bed. These thugs are swamping the dahlias but they do look great in a long bed.
    This was a new bed I created and the soil was crap. Threw some old compost over it and a bit of FBB and they have done very well.

    I too grew the dwarf variety last year and found them to be disappointing as they were very small, cant complain really as it does say dwarf on the packet  :)


    'The power of accurate observation .... is commonly called cynicism by those that have not got it.

    George Bernard Shaw'

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