hi the ground looks a bit dry so i would give them some water if you temp is as hot as that i would give them a good soak at night and early morning they should pick up give them time good luck.

Agree, they need more water, especially being in Southern California in the full sun. The soil looks very dry. Keep the soil moist. Consider mulching.

They look desperate for a drink! Especially being so newly planted and in the hot sun.

If you are on the coast, you will need to give them 3-7 gallons for their first watering, then about a gallon every other day for the next two weeks. Due to the lower humidity in the desert, they should be watered every day for the first two weeks, there. I would also think about if the root balls fell apart during planting, or, how hard did you work at "loosening up the roots"? It is difficult to overwater Lantana, as long as there is any drainage at all. In the long run, Lantana becomes semi-drought tolerant, but only after it has had a chance to grow deep roots.

Thanks folks! I still struggle with this whole watering thing... Too much vs too little ;(

I have been watering since, the smaller one seems to be responding a little better, I am hoping the other one begins to perk up a bit. Luckily the Indian Hawthorn I planted at the same time seems to be doing ok!

Just wondering if you could rig up some temporary shade until they recover, to cut down moisture loss from the leaves?

I would give them the good watering late evening, to give
the plant overnight to have a good drink.
Also rig up the shade.