Q.LED lighting around Weigela bushes–can they cause a kill?
I have two beautiful Wine & Roses Weigela bushes in my backyard. Until this spring they have been wonderfully full and growing healthily. This spring there is a huge amount of dead branches in the plant. After a mild winter, this is very unexpected. The only change in environment for these bushes was the additional small LED landscape lights last summer to up light the bushes. Is it possible the LED lighting killed the bushes? Yes, this seems ridiculous to me, but the dead areas are almost coinciding with the location of the lighting. The LEDs generate no heat…but ran on a 6 hour/day timer all winter (did not even melt the little bit of snow we DID get). While I am aware I can trim the bush back and reshape it, I’m concerned I have somehow damaged the plants with this small lighting. Help?
Though LED lights that run all night have been known to interrupt a plants normal growth, it's doubtful your low wattage landscape light is the cause of your plants die back.
It is more likely attributed to winter die back.
Prune back the dead parts of the plant.
https://www.gardeningknowhow.com/ornamental/shrubs/weigela/growing-weigela.htm
https://www.gardeningknowhow.com/ornamental/shrubs/weigela/pruning-weigela.htm