cosmos oddity (flowers, poinsettia, butterflies, spring)

[harry chickpea]

I planted cosmos early this past spring and they grew up tall and healthy but refused to bloom, even with bloom-booster fertilizer. Now that it is fall, suddenly there are blooms. I'm trying to figure out why that happened. Ideas?

[Zoisite]

It means you planted short-day cosmos, they require more hours of uninterrupted darkness than day light to flower. Here is an explanation about the difference between short day versus long day plants.

https://extension.oregonstate.edu/ne...ong-day-plants

Some good examples of short day plants are cosmos, christmas cactus, poinsettia and my favourite which is pineapple sage. It grows tall with many branches of luxurious foliage through spring and summer and at the middle of October when daylight hours are much shorter it starts to produce flower buds and then is coming into full glorious bloom with scarlet flowers by the end of November and into December.

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[elnina]

Interesting info about the long day/short day plants. Learned something new today. Thank you!

[Threestep2]

Originally Posted by Zoisite

It means you planted short-day cosmos, they require more hours of uninterrupted darkness than day light to flower. Here is an explanation about the difference between short day versus long day plants.

https://extension.oregonstate.edu/ne...ong-day-plants

Some good examples of short day plants are cosmos, christmas cactus, poinsettia and my favourite which is pineapple sage. It grows tall with many branches of luxurious foliage through spring and summer and at the middle of October when daylight hours are much shorter it starts to produce flower buds and then is coming into full glorious bloom with scarlet flowers by the end of November and into December.

.

Absolutely. I did not know the scientific reason but relied on pineapple sage as a last buffet for hummingbirds and butterflies for a long time. Our bush in OK is scarlet red and asking for guests.