From my perspective as an Osteospermum, the most important thing for you to understand is my growth and flowering cycle. I am a perennial, often flowering from spring right through until the first hard frosts of autumn. My blooms, my pride and joy, are produced on new, fresh growth. This is the fundamental reason why pruning is so beneficial for me. If you allow my old, spent flower stems to remain, I will put energy into producing seeds there, a process you deadheading. By removing these spent stems, you signal to me to redirect my energy into producing more vigorous vegetative growth and, crucially, a new flush of vibrant flowers. This simple act aligns with my natural desire to reproduce and results in a much bushier, more floriferous plant.
The most frequent interaction we will have is deadheading. This is not a harsh prune but a precise and gentle encouragement. Please look for a flower head that is fading, wilting, or has finished its show. Follow the flower stem down to the first set of full, healthy leaves or to a point where you see a new side shoot, known as a lateral, beginning to develop. Make a clean cut just above this point, using sharp, clean secateurs or your fingertips. This action does two wonderful things for me: it prevents me from wasting precious resources on seed production, and it prompts the growth hormones at the leaf node below your cut to activate. This will stimulate that lateral bud to grow into a new stem, which will itself produce flowers, making me denser and more rounded with each cut you make.
While deadheading maintains my shape during the flowering season, a more proactive technique early in the season sets me up for ultimate bushiness. This is called pinching. In late spring or early summer, when my new growth is several inches long, I would greatly appreciate it if you would use your thumb and forefinger to pinch or snip off the very top inch or two of my main stems. This might seem counterintuitive, but it is a tremendous help. By removing my primary growing tip (apical bud), you disrupt the hormone that suppresses growth from the buds lower down on the stem. This forces me to branch out from those lower nodes, creating two, three, or even four new stems from where there was previously just one. Repeating this process on the new growth a few weeks later creates an incredibly full, bushy framework from which an explosion of flowers can emerge.
After a long season of glorious flowering, I can become a bit leggy and tired-looking by mid to late autumn. A more significant prune at this time is vital for my long-term health and shape. Please cut my entire form back by about one-third to one-half of its current size. Make your cuts just above a set of leaves or a node. This hard prune serves several purposes from my viewpoint: it removes any old, woody, or potentially diseased material; it prevents wind rock damage to my roots over winter; and most importantly, it encourages a flush of strong, compact new growth from the base when the warmer weather returns. This prevents me from becoming straggly and ensures I start the next season with a robust, bushy habit, ready to support another spectacular display of flowers for you.
