I took this picture while driving behind a landscape company’s truck. Can you see the foliage sticking up out of the back of the truck? There is a nursery/supplier nearby and I suspect they picked up these plants at that nursery and are headed to their job.
It is so important to cover and protect while transporting plant material, especially deciduous plants. Subjecting the plants to the extreme exposure and winds of road travel without a tarp or other cover will cause the plant to dessicate, i.e. lose excessive amounts of moisture. There is a good chance these plants will be harmed enough to show visual signs of stress, partially or totally defoliate, and maybe even die.
I know of one nursery/supplier that will not let you leave their yard without properly covering the plant material you just purchased. And yet it amazes me that a “professional” landscape company would not have their people trained in one of the most basic rules of the trade.
If you are a homeowner and transporting plant material, bring an old sheet, painter’s tarp or purchase an inexpensive tarp at a hardware store. If you’re in the trade, make sure your trucks have tarps in their tool boxes and train everybody on the how to protect plant material. Anticipate the different types and sizes of plants, and the different ways they should be covered.
Nursery plants are in a compromised state to begin with. Do everything you can to protect them.