Does anyone have any idea what kind of plant this is? What caused it to die off in spots like this? How to encourage growth?

I just moved into a house (in Portland Oregon) and am trying to fix the look of this chain linked fence that is in our front yard by a busy road.

To my eyes, the leaves at the bottom of the last photo look like English Ivy (Hedera helix) which is an invasive in many areas, including Oregon.

http://www.invasive.org/gist/m...
http://pages.uoregon.edu/ecost...

English Ivy is pretty hard to kill and is invasive in some states. Maybe it got sprayed by someone?

Yes definitely Ivy. Fabulous plant!

Its hard to kill so I suspect the fence will be completely covered again by mid summer. It makes a great plant for covering chain link as it wants to grow up.

When it reaches the top of the fence it will change into its "arboreal" habit. This is when it will flower and fruit.

If you like the look, I'd just cut out any dead growth and it will fill in quickly. It is on the invasive list in the PNW, and is a real problem when it escapes into wooded parks. But, since you already have it established, you may just monitor it to be sure it doesn't spread. As Sue notes, when the leaves change to more of a heart shape, it is getting ready to flower and fruit. At that point, you may want to cut it back as the birds will eat the fruit and spread the seed. Here's an article you might be interested in.

http://extension.oregonstate.e...