I have a flower bed with bark and only rhododendrons. I am trying to
discourage grass and weed growth around them. Recently, I mistakenly
applied lawn fertilizer to the rhododendrons and it burned their leaves, but
luckily survived. Lawn fertilizers have a lot of nitrogen, which actually
caused the leaf burn. But this gave me an idea.

Instead of using weed killers, which might seep to the rhododendrons roots
after a rain, has anyone tried to apply a bad fertilizer to the lawn to
stunt their growth? Is this too far fetched an idea?

What might discourage grass growth? Something like 0-10-10?

Tom