I sow cosmos in late April every year to fill in any later gaps with leftovers going in a big pot. This year the ones in the ground are flowering well with large flowers and the ones in the pot are all tall foliage with a few small flowers. I have read that annuals under stress can flower well to ensure seed production and I suppose the pot ones are luxuriating in the good compost for the moment. I've noticed that when I pull them out at the end of the season they have a very small root system.
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