It is fading prematurely due to insufficient water. Water thoroughly until water comes out the drain holes, and see if it doesn’t perk up.

It has enough water. So insufficient water is not the reason. Yes it’s a terrace but it’s not hot enough yet. Very cool temperatures. Could it be too much water? Or something else? Infestation?

But you may be right, they may not like direct sun for to long (is that right?). It’s still not hot outside, quite pleasant but I noticed the flowers were pretty perky in the morning, and now after probably 5 hours of sun they are drooping. Not because of drying. Unfortunately I don’t have the luxury of moving to shade, part shade/part sun. So I’ll just have to deal with this…. Thank you for the comments

Can you raise the pots up by placing in a stand of some sort?

debra

Fertilizing before blooming (a big one), warm temps, direct sun, wind, low humidity, blooms getting wet, can all work independently or in concert to shorten the bloom period and cause blooms to go over faster. Anything sound familiar?

Too much water is also a potentiality because the low oxygenation that accompanies it limits the plants ability to take up and efficiently move water to the plant's most distal parts, which would be leaf tips, leaf margins, and blooms, while blooming. How do you determine when it's time to water? Do you allow water to collect in the saucer and be reabsorbed by the plant?

Al

Hi Al, yes some of those do sound familiar. There’s wind as it’s a quite exposed terrace, it was still pleasant cool weather in May but yes very direct sunlight for a while. I’ll see next year. In the meantime now they got small black dots under their leaves - pests of some sort, trying to deal with that. I just love when they’re in full bloom in spring when nothing else is in bloom (they bloom here mid to end may) so I’ll keep trying… thank you everyone for all the answers. Now it’s July and it’s SUPER hot so I’m dealing with droopy dahlias that I thought love full sun (apparently not that strong and full sun as is now in July).

@Ken - what type of medium should I use to help keep cool when it’s too hot outside?

they are shade plants in your z7... no media is going to overcome the fact the the plants can not cope with full blinding blistering sun on a brick surface...

if you move the pots into the mid day shade.. that would be the best you can do... they wont mind full sun at dawn and dusk ... there usually isnt any heat associated with those time periods...

boy.. should have done some spellchecking on that first post.. lol ...

ken

  Ken I know it might be a bit expsive    a dolly the type they put  packages on or furniture on  they will  have they  wheels  to move them back and  forth

 Howard