What zone are you in? I didn't think Abelia grew well anywhere south of 9a. I could be wrong. The UF sites says it will grow down through 9b, but I'm sure that was written before it got so much hotter. I think they need to reclassify some plants to 9a only.

You might have something there although they were bought in this area. I will contact the producer.

The USDA hardiness zones only apply to cold tolerance. There is nothing in that system that addresses summer heat and humidity or rainfall. Why they even bother to assign an upper level is a bit of mystery and is just confusing to most plant consumers.

Abelia x grandiflora can grow in very mild (summer hot) climates - it is commonly planted even in SoCal z10!! It is even commonly sold and grown in Hawaii (z11). I would question the watering practices first.........15 minutes daily may be too much or not enough, depending on your soils. Automatic sprinkler systems are seldom designed with the best interests of the plants in mind - even lawns in the hottest parts of the country do not require daily watering. And daily but shallow (short term) watering leads to plants without well-developed root systems. It is far better to water less frequently but of a longer duration so that the water penetrates deeply into the soil profile.

FWIW, glossy abelia is very heat and drought tolerant once established. I would cut back the watering to once or twice week but for a longer period - as much as 40 minutes to an hour. Use a soaker hose, drip system or even just the open hose end on a very slow trickle rather than the automated system. They are useless for the best irrigation of trees sand shrubs and a huge waste of water - as much as 80% is lost to evaporation.

Thanks! I'll try that and see what happens. It's easy enough to adjust. I have a ground level line with bubblers.