Topic: Cosmos not flowering

[caroline7758]

In an attempt to brighten up my garden(having not planted anything new as selling the house), I bought some Cosmos plants from Wyevale. they are nice and bushy but have no sign of flowers. Googling shows this to be quite a common problem but with no definite reason- people suggest too much water or too much feed as they apparently grow like weeds in Brazil.

Can anyone give me any hope that they will flower eventually?

[Deb P]

I think it depends on the variety: I'm quite new at growing Cosmos, but have tried several different varieties this year. All sown at the same time, I have several plants that have not flowered yet, others have been flowering for months?! Hopefully yours are just later flowering varieties!

[caroline7758]

Just heard exactly this question on GQT. They reckoned either too much nitrogen/not enough potash, or poor seed.

[Deb P]

I guess a nice liquid feed wouldn't hurt then.....I'll try it on my barren ones then!

[Obelixx]

Make sure it's tomato or seaweed and not high in nitrogen.

[ancellsfarmer]

OP says they grow like weeds in Brazil, so are they likely suited to washed out barren land? Reckon you've done them too well, most plants flower/go to seed as a means of species survival, especially when attacked, starved, drought threatened.
Starvation would be my suggestion!!  Just my view.

[ed dibbles]

My approach is that annual flowers generally do better on poorer soil because the good life discourages flowering. The situation is the opposite for veg because for greens we want to discourage flowering. (brassicas, lettuce, spinach etc.) or we want large plants before flowering to increase yield. (beans, toms, squash etc.) So we feed the veg heavily.

Like you last year some of my cosmos, variety purity, did not begin flowering until the beginning of September from a spring sowing. By the time they were in their prime the frosts began and while they struggled on for a bit providing late forage for bees they were not looking good.

This year my cupcakes cosmos flowered early and are still looking good now. Another year they may do the opposite.

My experience of cosmos over a number of years is that this unreliable flowering is just in their nature.

[Deb P]

Mine are on average soil, the ones not flowering are from a mixed variety seed packet, and in the patch of about 12 plants, three are almost over, three tall but not flowering yet, the rest are still covered in flowers, so I think in my case it's the variety making the difference. I like growing them through other plants such as roses, dahlias and my new favourite single coloured Gladioli, I never thought I'd grow any of these!

[caroline7758]

An update on this- my first flower is just opening and all the plants have buds, so guess they were just late starters. Just hoping they're not too late to get some decent blooms, although it would be better if they would stay in bud until we move the pots to our new house in 2 weeks' time!

[Deb P]

Uodate: my nonflowerer is about five foot tall and still hasn't flowered! It has got some buds on it, I'm curious now what colour it is!