Cordyline australis Discoloration: Sun, Water & Nutrient Balance

Your 'Red Star' cordylines on an east-facing Australian deck show yellowing top foliage while lower leaves and new center growth remain colorful. The one in more shade looks fine. Here's the diagnostic checklist.

Top 3 Causes

1. Watering extremes. Soggy soil (poor drainage) yellows tips; so does chronic underwatering in heat. Check: pot must drain fully. Water deeply when top 2 inches dry.
2. Nutrient imbalance. Excess nitrogen burns tips; long-term pot without feeding causes deficiency yellowing. Apply slow-release balanced fertilizer (e.g., 10-10-10) in spring, or liquid feed monthly during growth.
3. Sun exposure. Cordylines prefer full sun but tolerate part shade. Intense morning-to-afternoon sun in pots can stress roots if soil overheats. The shaded plant's health supports this.

Action Plan

• Repot any with circling roots into fresh, well-draining mix.
• Mulch pot surfaces to moderate soil temperature.
• Fertilize moderately; avoid high-nitrogen lawn fertilizers nearby.
• Monitor new growth — if it stays colorful, the plant is correcting itself.

Cordylines are tough. Address drainage and feeding, and they'll rebound with that signature burgundy glow.