Can't see it all that well but maybe this is a vine? that's what it looks like to me.the flowers are wisteria like in structure......
if no one i.d.s it, i'd suggest you try google searching for yellow flowered vine or going to the brushwood.com site and doing same.
best,
mindy

maybe it's a laburnum, goldenchain tree. if the leaves are alternate trifoliate?

Here is a link that might be useful: laburnum

Another Gardenweb member emailed me with the ID of this plant. It's Melilotus officinalis. I compared pictures of the plant on-line with my friend's plant and that is what it is.

Thanks for responding to my message, mindy. I'm pleased that we now know what's growing in my neighbor's yard.

Linda

Just wanted to add that this is listed as an invasive weed in areas as diverse as WI and the southeast. So your neighbor might want to rethink whether she wants this in her yard.