Half of my backyard is a steep bank that gets lots of sun..........?

Hi:
There are also many evergreen shrubs that would do well on your steep bank. I am a landscaper and designer and live in an area where there are many banks and slopes. One thing you can do is to put down a commercial landscape fabric called Jute. This is made for erosion and banks. It is made out of burlap. I will link you to the simple solutions of my website. There is a page on slope planting with evergreens. You may be able to get some ideas from this page. There are a variety of Junipers that act as a ground cover. I will link you to the gallery of plants section as there is a page on Junipers. Many of these plants are low maintenance. Great ground covers also are:

Creeping Thyme
Creeping Rosemary
Pachysandra

I will also link you to the site map, as this page has everything that is on the website. Browse through and see if you can find any other information that may help you. Good luck to you and have a great day!
Kimberly

http://landscape-solutions-for-you.c...

http://landscape-solutions-for-you.c...

http://landscape-solutions-for-you.c...

Some of the creeping herbs are great for holding a bank as they root where they touch. Try Oregano, Golden Marjoram or some of the low growing creeping Thymes. Not only will they hold the bank but you will be invaded by butterflies and bees after the nectar.
http://ottawahortiphilia.blogspot.com/20...
http://mountainvalleygrowers.com/ori...
Some of the low growing Sedums would look good too.
http://ces.ncsu.edu/depts/hort/consu...
All of these will thrive in hot sun and they are all easy to control as well.

Below is link to a plethora of ground cover plants all of which are good.
If I might make a suggestion and excellent ground cover would be daylillies they multiply quickly of course you probably want some sort of evergreen which is perennial and doesn't go dormant in winter.
You really need to decide according to your hardiness zone.
Pachysandrais for shady areas, not sunny
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excellent choice for evergreen
Blue Rug Juniper Plants
Ornamental grasses they will go dormant but leave a beautiful fall and winter color as well as wildlife habitat.

English Ivy

http://landscaping.about.com/od/groundco...
http://landscaping.about.com/od/groundco...

I love Kimberly's answer.
The birds would love you if you planted some strawberries in between while waiting for the bushes to grow and fill in.
Whatever you do, don't let anyone talk you into blackberries.