Topic: Cosmos

[Palustris]

Just been asked by a good friend about thnese plants, never grown them so no ideas. Question is, does one pinch out the tip to encourage branching or do they naturallly branch as some other plants do?
Have tons of info on the varieties etc., but not one book says how to grow them on!

[Gardengirl]

I am in the same quandry Eric.  I obtained some via swaps last autumn with Lady Cosmos (who incidentlly is the expert on these plants).  She did say they liked sandy soil and that they should be left in clumps when planting out the seedlings.  I would be interested to know if any pinching out is required.

Pat

[Ceratonia]

Don't think there's a hard and fast answer. We grew hundreds of Cosmos last year - I pretty much filled up anywhere that had a gap in May with them. Very good cut flowers for the house.

They do produce a long primary stem if you don't pinch out. If you're growing the taller varieties like Versailles that's probably what you want - looks quite effective when a number are grown very close together.

The more dwarf ones (eg Sonata) which you want to be bushy should be pinched out, of course.

[Marianne]

Hi Eric,

I buy them every year as twigs.  Pinch out the centre and they would grow upwards and outwards.

They have never failed me.  In fact, will post a picture when I am home - they flower well into autumn and are absolutely gorgeous !
 ;)

[simon404]

I'd agree, pinch them out. I grew "polidor" and "ladybird scarlet" last year and they still reached at least 3 feet.  :)

[Marianne]

This cosmos was bought as a single twig and grew rather big, and bi-coloured too !



I am now growing clematis, jasmin and ivy up that ugly fence.  Can't wait for it to be covered !

[Charlotte Sometimes]

I grew Cosmos "Daydream" last year, and don't recall pinching out the growing tip... they did fine!  But then I wanted them tall.   ;D

[Val]

Has anyone got the chocolate one? I put it in last year and I've heard it can be slightly tender it hasn't made an appearance yet should it have done by now?

[Marianne]

Yes I too read about the chocolate cosmos but have never seen one.  Maybe they are only available from very expensive nurseries  ???

[Ceratonia]

Cosmos atrosanguineus is chocolate cosmos. I have one in a pot which I bring in over the winter. It forms a tuber like a dahlia and doesn't like a hard frost. The flowers are more maroon/black than brown I would say and the chocolate smell is only very faint, although more noticeable on a warm evening. I got mine from a neighbour - she was propagating by dividing the tubers, but I've certainly seen seed advertised in quite a few catalogues. Flowers last for ages, but the foliage gets quite messy.

Val - Just checked in the greenhouse and mine has not made an appearance yet. I seem to recall last year that the foliage didn't appear until May or even June - I think I was on the verge of chucking it out. My neighbour leaves hers in the ground over-winter with some mulch. I think wet is probably more of a problem than cold.

[Marianne]

Hi,

I am puzzled now as I thought cosmos was an annual that died down at the first signs of frost.  Mine certainly do.   ???Are the chocolate ones hardy ??? 

[Gardengirl]

I had a chocolate one in the garden.  It lasted about three years before 'pegging out'.  I seem to remember someone on GW saying that they are hardy, but to take cuttings just in case.

[Marianne]

Thank you Gardengirl !
 :D

[Val]

Thanks everyone, I think probably this year if it appears I'll be taking cuttings.

[Marianne]

I wish you luck Val ! :D