Don't know if I'm too late commenting on this. I live in a flat and have 2 hebes on my balcony. It looks like they've been sun damaged underneath... The top leaves are still green but the underneath looks just like dried brown wood and the leaves are all brown and dry... Is there a way to bring them back to life? I may have forgotten to water them a few times but am watering them again now... Hope someone can help!
If the tips look lively it's not dead. Hebes are fast growers, you need to keep up with the food and water. How big a plant and pot?
While there is still green there is hope
Sounds like dried out but are you sure they are not potbound? This would make them dry out much faster to the point where they can get so potbound that the water doesn't even penetrate. If they are, repot, if not just keep up with the watering and hope for new sprigs of life to shoot lower down. Unfortunately most Hebes are notorious for getting leggy anyway so if it takes too long for them to green up I would give up and treat yourself to some new ones.