The cloudless sulphur is a common resident in my backyard. However, from late summer into fall, it is one of the most abundant butterflies my wife and I see nectaring at the flowers growing in our flowerbeds. However, the numbers of cloudless sulphurs we spot throughout most of the spring and summer pale in comparison to what we are seeing right now.
A couple of days ago, as soon as I stepped out onto my deck, my eyes were immediately drawn to all of the cloudless sulphurs feeding or hovering above our Turk’s cap. When I approached the plant it seemed cloudless sulphurs were everywhere. This prompted me to try to count the multitude of butterflies that had congregated on this single, sprawling shrub. This proved to be quite a chore, as I could not see the entire plant at one time. However, after several attempts the best that I could do was count at least 28 of the large, bright yellow butterflies.
The cloudless sulphurs had descended on this perennial shrub to feed on the nectar harbored in its brilliant red, swirled flowers. 
Until recently, the clear yellow butterflies had to share this bounty of nectar with a swarm of ruby-throated hummingbirds. In fact, before most of these amazing little birds moved on south toward their winter homes, rubythroats far outnumbered cloudless sulphurs dining at this drought-resistant shrub.
This sight of so many clear yellow butterflies feeding at the stunning red flowers against a backdrop of dark green leaves is truly breathtaking. However, as much as I wish this spectacle would not end, I know, from experience, I had better enjoy it while I can. Soon many of these butterflies will continue towards their winter home.
If you want to set the stage for this colorful event in your backyard, make a point of adding Turk’s cap to your home landscape. If you do plant Turk’s cap in your yard, have a little patience. There is no way you are going to attract large numbers of cloudless sulphurs right away. In my case, as the shrub grew larger from year to year, it produced more blossoms, which, in turn, caught the attention of more cloudless sulphurs.
If you are eventually as successful in attracting as many cloudless sulphurs as I have been, I am certain you will feel your patience was handsomely rewarded.
“If you do plant Turk’s cap in your yard, have a little patience.”
Please quantify “little”.
Backyard Gardener,
Thanks for your comment. What I mean was it seems the largest numbers of butterflies are attracted to plantings that have large numbers of blooms. Consequently, when the plant is just getting started, don’t expect to the big numbers of cloudless sulphurs. However, it have the patience to wait for the planting to get larger, you should be rewarded with lots of butterflies. In the meantime, though, you should attract some hummingbirds, cloudless sulphurs, gulf fritillaries and the like every year.