In the Bible (and in life), the idea of withering is usually connected to plants, and plants generally wither if they don't get enough water. Plants represent individual facts and thoughts, and water represents natural truth, or true concepts about life on an external level. To wither, then, generally means that disconnected ideas will not be remembered and will be useless if they are not sustained by deeper concepts that lead to good actions in life.

To wither, as in Psalm 1:3, means to dry up, or to lack good and truth. (Apocalypse Explained 419).

In Psalm 102:4, this signifies that the truths of good seemed to be dying. (Apocalypse Explained 403[6])

'Withering and drying up,' as in Ezekiel 17:10, referring to the east wind, signifies a state when there is no good or truth.

In Matthew 13:6, "wither" signifies the truths of good adulterated and dying. (Apocalypse Explained 401[35]).

Withering, as in Matthew 21:19, signifies the failing of truth and good in the natural. (Apocalypse Explained 403[21]).

(References: Arcana Coelestia 6693 [2], 6726, 8699, 8902 [6]; The Apocalypse Explained 518 [12], 627 [9])

6726. 'And put him in the weed at the bank of the river' means that at first it was among false factual knowledge. This is clear from the meaning of 'the weed' as factual knowledge, dealt with below; and from the meaning of 'the river of Egypt' as falsity, dealt with in 6697. For what this really means, that those who are introduced into God's truth are at first put among falsities, see just above in 6724. The reason why 'the weed' means factual knowledge is that every small plant mentioned in the Word means some type of factual knowledge. 'The weed' which grows at the bank of a river is inferior factual knowledge, as also in Isaiah,

The rivers will recede, and the streams of Egypt will dry up; reed and weed will wither. Isaiah 19:6.

'The rivers' stands for matters of intelligence, 2702, 3051; 'the streams of Egypt will dry up' stands for matters of knowledge; 'reed and weed' stands for the lowest forms of factual knowledge, which are sensory impressions. 'The weed' stands for false factual knowledge in Jonah,

The waters surrounded me, even to my soul, the deep closed around me, weed was wrapped about my head. Jonah 2:5.

This prophecy describes a state of temptations. The waters which surrounded him, even to his soul, are falsities, 'deluges of water' being temptations and desolations, see 705, 739, 790, 5725. The deep which closed around him is the evil of falsity. The weed that was wrapped about his head stands for false factual knowledge that beset truth and goodness. This is how it is in a state of desolations.