Troubleshooting
Coast Rock Cress problems — and how to fix them
Coast Rock Cress (Arabis blepharophylla) 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.
Summer root rot
The most common failure: overwatering during summer dormancy in Mediterranean climates causes fatal root rot. Treat like a bulb — withhold irrigation almost entirely from June to September.
Poor performance in hot, continental climates
This species is strongly adapted to cool, mild coastal conditions. In regions with hot summers above 30°C, it struggles and often dies out. Reserve for USDA Zone 7–10 gardens with mild summers or grow in containers that can be sheltered.
Aphid infestations on new spring growth
New growth in late winter and spring can attract aphid colonies. Blast off with a strong jet of water or apply insecticidal soap spray. Natural predators (ladybirds, lacewings) are usually effective outdoors.
Prevent coast rock cress problems before they start
Most coast rock cress issues are care-mismatch, not bad luck. Dial in the basics:
Coast Rock Cress problems — FAQ
Why is my coast rock cress summer root rot?
The most common failure: overwatering during summer dormancy in Mediterranean climates causes fatal root rot. Treat like a bulb — withhold irrigation almost entirely from June to September.
Why is my coast rock cress poor performance in hot, continental climates?
This species is strongly adapted to cool, mild coastal conditions. In regions with hot summers above 30°C, it struggles and often dies out. Reserve for USDA Zone 7–10 gardens with mild summers or grow in containers that can be sheltered.
Why is my coast rock cress aphid infestations on new spring growth?
New growth in late winter and spring can attract aphid colonies. Blast off with a strong jet of water or apply insecticidal soap spray. Natural predators (ladybirds, lacewings) are usually effective outdoors.