Should I pinch the dead flower once it blooms (deadhead)?
Yes, you should regularly dead head the spent flowers.
Here is a link with more information.
My African daisy used to bloom but it stopped in the summer and hasn't bloomed since.
There are two flowers that I know of with this name, and I am unsure of which you have, but I will include articles for both. It could be a fertilization issue if it is the Gerbera daisy, or a temperature issue if is it the type of marigold known as the African Daisy. These will not bloom in warm temperatures.
These article will help:
I have several African Daisy Plants. I bought them already bloomed. Them all of the blooms just dried up after a couple of weeks and no more have bloomed. Can you tell me how to make them bloom again?
When blooming, daisies require lots of nutrients. Apply an all-purpose fertilizer every month during their growing/blooming season. If using a liquid plant food apply weekly. After blooms become withered, cut dead leaves and blossoms to stimulate growth and produce more flowers.
Like deadheading pruning and pinching allows plants to remain bushy and continually produce flower blooms and reduces plant over-crowding.
Removing overcrowding foliage and stems will allow plants to receive plenty of sunlight.
can Dimorphotheca plant grow in sandy soil?
It would seem that they are more suited for clay soils, but they should be able to tolerate sandy soil types. This article will give you more information on the care of these: https://www.gardeningknowhow.com/ornamental/flowers/cape-marigold/growing-cape-marigold-annuals.htm
Flowers are dead. Two branches are bent and nearly dead How to prune? What items required to prune? I am 89 and new to plant knowledge
The African Daisy plant is not suited for indoor growing. They require full sun.
You can try to prune away the spent flowers and move the plant outdoors; you should make this transition to full sun over a period of a week or so.
Here are some links for you.
These were planted in the spring of 2017 and had large beautiful blooms. This year the blooms are very few and there is not signs of budding. There are numerous leafless stems as well. Do this need to be pruned back to support blooming?
Fertilize the African daisy in late winter or early spring, just before new growth begins and again in fall, using a slow-release, complete fertilizer with a formula like 6-10-4. Spread it out over the ground around the plant and water it in if no rainfall is anticipated.
Verify the NPK number in the fertilizer you used.
Too much Nitrogen in your soil can inhibit flowers.
My African Daisies (purple osteospurnum) were planted in Spring 2017 and bloomed like crazy. Despite fertilizing regularly this year they are not blooming much at all. Should I wait to see if it develops buds or does it need to be pruned/cut back? There are a number of long leafless stems on the plants.
This may be a case of over fertilizing; excess Nitrogen may give you a big leafy plant but little or no flowers.
A soil test is the only sure way to know what is happening in the soil.
These links have more information.