The answer to 'landscape design yellowing' is that there are several common causes, including nutrient deficiencies, disease, pests, and environmental stressors. Yellowing leaves can be a sign of issues like nitrogen or iron deficiency, fungal diseases, pest infestations, or drought and heat stress. The solution often involves addressing the underlying cause through proper fertilization, pest control, or adjusting watering and sunlight exposure.
In many cases, homeowners can troubleshoot and address minor yellowing issues themselves. However, if the problem persists or worsens, it's best to consult a professional landscaper or horticulturist to properly diagnose and treat the issue.