Quick answer
The problem is not having money but leaning on it. The verse contrasts a collapse with something green.
Read both lines
The verb in the first line is the tell: trusts. This book is not against wealth, and this same chapter has just said a generous person tends to prosper. What it identifies as fatal is treating riches as the thing that holds you up, because a support that can evaporate will eventually be asked to bear weight it cannot. The second image answers it with something living rather than something owned. Foliage is not impressive, but it is alive and it keeps coming back, and the comparison quietly says that the durable thing is a life rather than a holding.
Related: Proverbs 11:4 · Proverbs 23:4–5 · Psalm 1:3 · 1 Timothy 6:17
New King James Version®, Copyright © 1982, Thomas Nelson. All rights reserved. Full copyright information. Scripture provided by API.Bible.
Go Deeper
If this verse has been used to put weight on you that it was never carrying, ask about it directly.