I don't think that the slugs were after your Japanese maple tree. I think they were just escaping the rain. Every time it rains here, the slugs will climb up the sides of my house trying to reach higher ground. After the rain ends, I go around the house using my hand shovel to kill any that I find. This helps keep their numbers in check. Fortunately, they don't ever climb up my plant shelves and tables.

Often seen this in daytime...mind you I wouldn't see it at night.I've always assumed it might be to help escape predation but don't know for sure.They can devour sub 2year growth on JMs but usually only very early spring when there's nothing else about.

Just an update.
I have, still, a lot of slugs in the area of this tree.
When we went into this FULL BLOWN horrible heat/drought, the slugs quit climbing the trunk.

I think they just were because it was so wet.
Ick.

thanks all.

I think because of the wet weather they were after food that's not normally available to them. Slugs routinely climb trees here in western Wa. St.

Here's one 'rappelling' down out of a Japanese maple. :-)

Mike

Slugs love to climb my Gresham magnolias for some reason, but they don't eat the leaves or if so it's a few little nibbles. Very odd.

I have them climb my pecan and oak tree! Unbelievable