Morning Glories and setting suns

These are the morning glories that we started in February. Only four of the nine plants survived, but I am told that they will self-seed from this point forward. The length of daylight is getting noticeably shorter. The last two evenings I was mowing the grass until I could barely see and it was only 8:30PM when I came in. Officially, the sun sets at 8:00PM tonight. I was surprised to find that the length of daylight is about 3 minutes shorter each day (the length of daylight that we lose each day increases up until Autumn Equinox where it tops out at 2m 53s). By the end of September the sun will be setting at 7PM (September Sunsets). I had better setup some lights outside if I plan to do any gardening in the evenings this Fall.