Q.My African Black Daisies (Purple Ostepspurnum) are not blooming despite fertilization. Do I need to cut them back?
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.
https://www.gardeningknowhow.com/ornamental/flowers/african-daisy/african-daisies-osteospermum.htm