How to grow Dahlia (Dahlia pinnata)

Common problems

• Tubers rot before sprouting. Planted in cold, wet soil and watered too early. Wait for warm soil and hold water until green shoots appear.
• Tall stems snap or flop. Big blooms on unsupported stems. Stake at planting and pinch the growing tip to encourage branching.
• Holes and ragged petals. Earwigs or slugs feeding at night. Set traps, clear debris, and hand-pick after dark.
• Powdery white film on leaves. Powdery mildew in humid, crowded plantings. Space for airflow, water at the base, and remove affected leaves.