My sedum leaves are turning yellow and red and falling off, did I over water them, or did they get too much sun? I live in Minneapolis, MN zone 4, the pants are 2 years old and this is the second year they've done this.
Thanks for the picture of the gorgeous pond, but I don't see any Sedum there anywhere! If you're trying to grow them beside the pond, this is not their preferred conditions; they need good drainage, not waterlogging.
Plants that grow beside water in boggy soil are specifically adapted to that; some plants that actually like those conditions are Iris sibirica and Caltha palustris which have roots that are able to withstand constant immersion in water.
Sedum need to have sandy or even gravelly soil, which does not ever stay wet. As you may have found, wet soil doesn't do anything for them. Move the plants to higher ground, where they'll be much happier.
It's highly unlikely that they got too much sun - they love full sun and perform best there; however, if you live where it's really humid this can cause issues. Don't overwater the plants when the temperature and humidity is high.
Other problems that can cause similar issues are Anthacnose, a fungal infection that lives on the stems of the plants and overwinters there, and then reinfects the new growth in the spring.
You can prevent this by cutting the plants right down to the ground in early spring (I leave the stems on all winter to capture snow and provide shelter for overwintering insects).
Hope this helps get your Sedum back on track.
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