Troubleshooting
Coreopsis 'Sienna Sunset' problems — and how to fix them
Coreopsis 'Sienna Sunset' (Coreopsis 'Sienna Sunset') is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Colour fading in heat
Very high summer temperatures can bleach the warm sienna tones. In hot climates, light afternoon shade may preserve flower colour.
Crown rot
Waterlogged soils are the main threat. Ensure excellent drainage, particularly during winter.
Aster yellows
Phytoplasma spread by leafhoppers distorts flowers and foliage. Remove and destroy affected plants immediately.
Aphids
May cluster on new growth. Wash off with water or apply insecticidal soap.
Clump centre die-out
Divide every 3-4 years in spring to keep plants vigorous and free-flowering.
Prevent coreopsis 'sienna sunset' problems before they start
Most coreopsis 'sienna sunset' issues are care-mismatch, not bad luck. Dial in the basics:
Coreopsis 'Sienna Sunset' problems — FAQ
Why is my coreopsis 'sienna sunset' colour fading in heat?
Very high summer temperatures can bleach the warm sienna tones. In hot climates, light afternoon shade may preserve flower colour.
Why is my coreopsis 'sienna sunset' crown rot?
Waterlogged soils are the main threat. Ensure excellent drainage, particularly during winter.
Why is my coreopsis 'sienna sunset' aster yellows?
Phytoplasma spread by leafhoppers distorts flowers and foliage. Remove and destroy affected plants immediately.
Why is my coreopsis 'sienna sunset' aphids?
May cluster on new growth. Wash off with water or apply insecticidal soap.
Why is my coreopsis 'sienna sunset' clump centre die-out?
Divide every 3-4 years in spring to keep plants vigorous and free-flowering.