Cosmos bipinnatus in a late summer gardenOne of the absolute treasures of late summer is Cosmos bipinnatus, otherwise known as Mexican aster which makes you think of bright, clear colours and that’s what you get.

When I first started growing Cosmos, I would mistakenly buy plants from the local nursery and they would turn out to be the dwarf-sized Sonata series. Silly me, I didn’t pay attention and was disappointed they were not large and airy.

I soon learned we needed Cosmos bipinnatus Sensation and, buying them as small plants from local nurseries, I’ve been delighted at the way they fill the gaps later in the season.

This year, we grew Sensation from seed which have turned out to be magnificent plants but only four out of 10 have bloomed. The others have grown to an enormous size, some up to six foot and one is rather like a tree with its spreading, ferny branches.

So what’s afoot? Was it old seed? No. Have they been hit by cold and wet weather? No.

Are they in the shade? No. Have they had too much nitrogen? No.

They have been watered when necessary (not over watered) but I have to admit not adding bonemeal which might have encouraged flowering though I’ve never done so in previous years.

They were sown in pots in the greenhouse and planted out as small healthy plants about three months ago. Yes that’s right, three months. Yet Cosmos are supposed to take seven weeks from seed to flower.

Am I patient? No.