Troubleshooting
Limestone Saxifrage problems — and how to fix them
Limestone Saxifrage (Saxifraga callosa) 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.
Root and collar rot
Winter waterlogging or excessively moist compost causes Phytophthora or fungal rot at the base of rosettes; ensure the crown is on a raised, gritty collar and that water drains away freely.
Vine weevil
Vine weevil larvae (Otiorhynchus sulcatus) feed on roots over winter, causing rosettes to collapse suddenly in spring; inspect pot-grown plants and apply a biological control (Steinernema kraussei nematodes) in late summer.
Aphids on flower stems
Greenfly can colonise the flower spikes in spring; remove by hand or use an organic insecticidal soap spray, taking care not to wet the rosette centre.
Prevent limestone saxifrage problems before they start
Most limestone saxifrage issues are care-mismatch, not bad luck. Dial in the basics:
Limestone Saxifrage problems — FAQ
Why is my limestone saxifrage root and collar rot?
Winter waterlogging or excessively moist compost causes Phytophthora or fungal rot at the base of rosettes; ensure the crown is on a raised, gritty collar and that water drains away freely.
Why is my limestone saxifrage vine weevil?
Vine weevil larvae (Otiorhynchus sulcatus) feed on roots over winter, causing rosettes to collapse suddenly in spring; inspect pot-grown plants and apply a biological control (Steinernema kraussei nematodes) in late summer.
Why is my limestone saxifrage aphids on flower stems?
Greenfly can colonise the flower spikes in spring; remove by hand or use an organic insecticidal soap spray, taking care not to wet the rosette centre.