I bought two Rose of Sharon plants to give as gifts. One last year and the other several years ago. Both show no signs of life yet and it's June first. I told both plant owners that this shrub is a slow starter. Is it possible that both shrubs are now dead, or should we give them a bit more time?

Also the older one has grown well over the past few summers, but sets lots of buds and then does not bloom. It is planted right where the sidewalk and driveway meet.

Yes, Rose of Sharon are typically late emerging in the spring, yet by now there should at least be some sign that that will happen. Twigs should be pliable. Scrape the bark with your thumbnail and you should see a wet green color. A dry green is saying no moisture is making it up into the canopy. if the buds fall away when touched, they are dead. it is not uncommon for a Rose of Sharon to grow well for a number of years and then abruptly fail to leaf out in the spring. General requirements include:Full sun to partial shade; moist, well-drained soil; tolerant of alkaline soils. While the canopies may have failed, check near the soil line and look for any signs of sprouting.