The answer to 'why is my garden erosion' is that garden erosion is a common problem caused by factors like heavy rainfall, sloping terrain, poor soil quality, and lack of vegetation. Symptoms include visible soil loss, gullies, and plants washing away. To address garden erosion, you can try solutions like planting ground cover, installing erosion control barriers, improving soil quality, and regrading the landscape.
If the erosion is severe or you're unsure of the best approach, it's often best to call in a professional landscaper or erosion control specialist. They can assess the situation, identify the root causes, and recommend the most effective long-term solutions for your specific garden and property.