Should I cut off the yellow leaves?

Yes, you can snip them off with clean scissors to keep the plant looking tidy. This also helps you see if the yellowing is continuing to spread.

Can too much sun cause yellow leaves?

Yes, if the plant is in full sun and the soil dries out too fast, the leaves will yellow. Move the plant to a spot with partial shade during the hottest part of the day.

Great blue lobelia: yellow leaves, causes and fixes

Check these first

Touch the soil surface to see if it is dry or soggy.
Inspect the drainage holes to ensure they are not blocked.
Check the base of the stems for any signs of mushiness.

Likely causes

Drought stress
Possible
How to tell: The leaves feel crispy and turn yellow starting from the edges inward. This happens when the plant goes more than 4 days without a thorough watering.
What to do: Water your plant deeply until water runs out of the drainage holes. Maintain a schedule of watering every 2 to 4 days to keep the soil consistently damp.
Overwatering
Possible
How to tell: The leaves turn a pale, sickly yellow and the stems may feel soft or mushy. This occurs if the soil stays saturated without any drying time.
What to do: Ensure your pot has excellent drainage holes so excess water can escape. Allow the top half inch of soil to feel just barely dry before watering again.

Yellow leaves on other plants

Find out what's wrong with your great blue lobelia

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.

When to worry

Worry if the yellowing spreads rapidly across the whole plant within a few days. It is normal for the very oldest, lowest leaves to yellow and drop as the plant grows.

Stopping it coming back

Keep the soil consistently moist but never sitting in standing water. Mulching around the base can help retain the moisture this plant craves.

Great blue lobelia: yellow leaves? Check yours with a photo

Every plant is a little different. Take a photo of your great blue lobelia and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

Get the app · Or check it from a photo now, free

Questions people ask

Should I cut off the yellow leaves?: Yes, you can snip them off with clean scissors to keep the plant looking tidy. This also helps you see if the yellowing is continuing to spread.
Can too much sun cause yellow leaves?: Yes, if the plant is in full sun and the soil dries out too fast, the leaves will yellow. Move the plant to a spot with partial shade during the hottest part of the day.

Guides to these causes

Dehydration

Why are my Great blue lobelia leaves turning yellow?