As a species of Osteospermum, thriving in the intense heat of summer is in our very nature, originating from the sun-drenched landscapes of South Africa. However, even we have our limits. To help you help us not just survive but truly flourish during the hottest months, here are our top five requests.
Our roots crave a deep, penetrating drink rather than a frequent sprinkle. Light, shallow watering encourages our roots to stay near the surface, where the soil dries out quickly and we become vulnerable to heat stress. A long, slow soak that moistens the soil to a depth of 6-8 inches guides our roots downward, where it's cooler and more moist. This creates a resilient, self-sufficient plant. Please check the soil moisture before watering; if the top inch is dry, it’s time for that deep drink. Early morning is the ideal time, allowing our leaves to dry before the harsh sun arrives and minimizing water loss to evaporation.
While we are sun-worshippers and require a minimum of 6-8 hours of direct light to produce our best blooms, the relentless, scorching afternoon sun can be overwhelming. This intense heat can cause our metabolic processes to go into overdrive, leading to wilting and a slowdown in flowering. If possible, planting us in a location where we receive light afternoon shade from a tree or structure is immensely beneficial. This brief respite from the strongest rays is like a cool siesta, allowing us to conserve energy and resources for vigorous growth and blooming rather than mere survival.
Blooming profusely in high heat is an energetically expensive endeavor for us. We exhaust a significant amount of nutrients, particularly phosphorus and potassium, which are vital for flower production and root health. A light application of a balanced, water-soluble fertilizer or a formula specifically designed for blooming plants every 4-6 weeks during the summer can make a world of difference. However, please avoid heavy, high-nitrogen fertilizers, as they will encourage an excess of weak, leafy growth at the expense of our beautiful, heat-tolerant flowers.
Our greatest fear is "wet feet." Soggy, compacted, or poorly draining soil is a death sentence for our roots, especially when combined with high temperatures, which can quickly lead to root rot. We insist on a home with exceptionally well-draining soil. Amending garden beds with compost, perlite, or coarse sand ensures the perfect structure. For those of us in containers, a high-quality potting mix and pots with ample drainage holes are non-negotiable. This ensures that after our deep drink, any excess water can flee quickly, leaving our roots happily oxygenated and healthy.
To keep us looking our vibrant best and channeling energy into new growth, a practice known as "deadheading" is essential. This simply means gently removing the spent, faded flowers by pinching them off at the base of the stem. This prevents us from wasting precious energy on seed production and instead signals the plant to initiate a new flush of buds. Furthermore, if we become leggy or overgrown in mid-summer, a light trim—cutting back by about one-third—will revitalize us, promoting a denser, bushier form and an explosion of new blooms as the season continues.
