Troubleshooting
Joseph's Coat Amaranth problems — and how to fix them
Joseph's Coat Amaranth (Amaranthus tricolor) 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.
Aphids
Can build up on soft growing tips; treat early with insecticidal soap or neem oil.
Root rot in wet soil
Amaranthus will not tolerate waterlogged conditions; improve drainage before planting.
Fading leaf colour
Almost always caused by insufficient sunlight; move to a sunnier position.
Caterpillars
Some moth caterpillars feed on Amaranthus foliage; pick off by hand or apply Bt (Bacillus thuringiensis) if severe.
Self-seeding
Produces copious seed and can self-sow prolifically; deadhead if spread is not desired.
Prevent joseph's coat amaranth problems before they start
Most joseph's coat amaranth issues are care-mismatch, not bad luck. Dial in the basics:
Joseph's Coat Amaranth problems — FAQ
Why is my joseph's coat amaranth aphids?
Can build up on soft growing tips; treat early with insecticidal soap or neem oil.
Why is my joseph's coat amaranth root rot in wet soil?
Amaranthus will not tolerate waterlogged conditions; improve drainage before planting.
Why is my joseph's coat amaranth fading leaf colour?
Almost always caused by insufficient sunlight; move to a sunnier position.
Why is my joseph's coat amaranth caterpillars?
Some moth caterpillars feed on Amaranthus foliage; pick off by hand or apply Bt (Bacillus thuringiensis) if severe.
Why is my joseph's coat amaranth self-seeding?
Produces copious seed and can self-sow prolifically; deadhead if spread is not desired.