'A shrub' or 'plant,' as in Genesis 21:15, denotes perception, but so little that it is hardly anything, in same way as 'trees,' but to a lesser degree. So 'to be cast under one of the shrubs,' signifies being destroyed regarding truth and good, to the point of desperation.

(References: Arcana Coelestia 2682 [1-3])

The idea of "lifting" is used in a number of different ways in the Bible. In general, it means connecting with a higher spiritual state for strength or enlightenment, though as with many verbs the context makes a great deal of difference. One of the most common uses comes as people lift up their eyes, which usually means coming into a state of perceiving what is true from the Lord. Lifting a hand or a rod means wielding power, making it common in the performance of miracles. Lifting the feet means elevating the most natural, external aspects of our day-to-day lives. Lifting objects means elevating them to higher uses, or sometimes just to protect them (Noah's Ark was "lifted up" in this sense). And so forth. In the negative sense, people can lift things up -- towers or other human structures -- representing a deeper state of the love of self.