We have had 17 days in the over 100 degrees this summer and it is mid August. It is a little off beat but it works. Dan Trimmer told me a couple summers ago how to make hard to set seed plants set pods. So i will share what i have done. As hot as it is we still have plants in rebloom here in central Arkansas.
I had a clump of Boundless Beauty that was begining to rebloom. I think 4 scapes were ready to bloom. When the blooms started to open i dug the clump with the dirt left on the roots. I cut the root ball big enough to fit a 3 gallon pot(plastic). I did put potting mix in the bottom about 2 inches deep and after putting in the root ball i added potting mix to the sides. Leave plant outside and water thoroughly.
Next morning bring plant inside and if you have some light comming in a window on the south side thats where i would put the plant. I have glass doors on the back porch so that is where i put my pots. The plants stay inside for 3 days and go outside 1 day for watering. I used frozen pollen and fresh pollen depending what i wanted to use. This went on for about 3 weeks. i set a total of 24 seed pods on this pot. After bloom is over i moved plant outside in part shade so the plant could recover as it finished off the pods. 3 inside and 1 outside. I have tried this on 4 different plants and it works. I hope you will give it a try. I did cut the blooms off short so there wasnt as much weight on the ovary. you will see in the photos the pods are shedding the old bloom.
This bloom is a 7 inch dip seedling with a height of about 40 inches. We hope you had a great bloom season. jim