blooms were plentiful and healthy one day and next the blooms are closed and look like they are dying
Each Gazania flower does not last long. They close up each night.
Frequent deadheading of the spent flowers will encourage more flowers.
DO GAZANIA TREASURE FLOWERS REQUIRE FULL SUNSHINE?
The sun makes them open, while shade and overcast makes them close. This article should help
I have a large tub of Gazanias which have always bloomed, but this year they have spread well and are quite robust, but so far there are no blooms. I water every couple of days, so could I be over watering?
They could need to be divided and spaced out more if this is the same container they've been growing in for years now. Also the soil medium could be leached of the nutrients they need to bloom and fertilizing could help
Should the flower be deadheaded when it dies off?
Deadhead the plants on a regular basis. The plants will benefit from being deadheaded because less of the energy is put into making seeds.
I planted the gazanias as ground cover 2 years ago. They filled in nicely but now are beginning to get bear spots - leaving just the long vines with no leaves or flowers.
You can take cuttings to fill in empty areas.
I don't think it sounds lazy. There will be weeding for the 2-3 weeks it takes Gazania seeds to germinate and throughout the growing season. Some weekly weeding in exchange for a colorful yard and no lawn care is a good trade. Make sure to purchase the true perennial or groundcover gazania. The flowers aren't as big or dazzling but plants are more reliably perennial. Watering until the plants are 4-6 inches to get them off to a good start while the roots get established. Have fun. https://www.gardeningknowhow.com/ornamental/flowers/gazania/gazania-treasure-flowers.htm
how and when do I propagate and or split gazania plants
Thank you for including a picture. What you have are blanket flowers, Gaillardia, not Gazania. They are lovely flowers and known to bloom all summer until frost. They are termed a "short-lived" perennial and 3 years is about all one can expect of them. Saving seed is easy: store seed over winter in a jar in the refrigerator. In spring, after danger of frost is past, sow the seed outdoors, cover lightly and keep the ground moist, not wet. Of course, start seed earlier indoors if you wish. In late spring (they don't come up early) check your plants and divide them once they have fully emerged. The plant self sows so you may not need to divide them.