Pocket Botanist
Check these first
- Look under the leaves for tiny insects.
- Check for yellow or brown patches on the foliage.
- Ensure the plant has good airflow.
Likely causes
Downy Mildew
Most likelyHow to tell: You will see yellow patches on the leaves that eventually turn brown. This happens during periods of high humidity.
What to do: Improve air circulation by spacing your plants further apart. Avoid overhead watering to keep the foliage dry.
Aphids
PossibleHow to tell: Small insects cluster on new growth and leave behind sticky residue or tiny discolored spots. You might see the bugs themselves on the stems.
What to do: Spray the plant with a gentle stream of water to knock the aphids off. For heavier infestations, use a mild insecticidal soap.
Find out what's wrong with your sweet alyssum
The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.
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When to worry
Small spots are rarely fatal, but they can spread quickly if left untreated. Worry if the spots cover most of the leaves or cause the plant to stop blooming.
Stopping it coming back
Water at the base of the plant to keep leaves dry and check for pests weekly.
Keep your sweet alyssum healthy from here
Save your plant in Pocket Botanist and you get care reminders timed for this plant, plus a care history that shows what worked. Identification and a health check are free.
Questions people ask
- Can I use a fungicide for the spots?
- You can, but improving air circulation and keeping leaves dry is usually more effective for Sweet Alyssum. Use fungicides only as a last resort.
- Are these spots contagious to other plants?
- Yes, fungal spores and aphids can easily move to nearby plants. Isolate the affected plant until it is healthy again.
More problems with Sweet Alyssum
Back to the Sweet Alyssum guide
This article was generated with AI from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.