I am looking for advice on planting a hedge to serve the following functions:
-Minimal or Easy Maintenance (For example, I wouldn't mind cutting down butterfly bushes once a year in the fall, so that they could spring back to life the next year...but, I don't want anything with thorns, selective pruning requirements, or reseeding requirements. The ideal scenario would be zero maintenance though.)
-Self Fertilizing (Nitrogen)
-Potentially a source of food or other useful materials. (However, this may conflict with my goal of deterring deer).
I plan to plant the hedge along a fenced-in garden. I would like the hedge to be tall/thick enough, once full grown, to deter any deer from jumping into my garden.
Do you have any plant recommendations for Zone 8A? I hope to plant enough variations in the hedge so that disease cannot take over the entire hedge at once.
How about a Fedge? You can make a great one that would be dense enough to keep animals out / in, provide a habitat for other animals, and food for you and the animals.
Most hedges need pruning to ensure a dense and low profile.
Serviceberry, Mulberry, Elderberry, Broom, Gorse as suggestions.
".....It is a suckering shrub which develops new plants from the roots and forms dense thickets 1–1.50 m tall with stems densely covered in numerous short, straight prickles 3–10 mm long. The leaves are 8–15 cm long, pinnate with 5–9 leaflets, most often 7, each leaflet 3–4 cm long, with a distinctly corrugated (rugose, hence the species' name) surface. The flowers are pleasantly scented, dark pink to white, 6–9 cm across, with somewhat wrinkled petals; flowering occurs in spring. 
The hips are large, 2–3 cm diameter, and often shorter than their diameter, not elongated; in late summer and early autumn the plants often bearfruit and flowers at the same time. The leaves typically turn bright yellow before falling in autumn....."
The reason I bring this up is that I think cuttings planted in situ provide a really cost effective approach that is attainable by more folks.. both in the cost of stock and in site prep.
I think that many (most?) plants that make food for us are eaten by deer... so some protection during establishment is useful... and I think the species mix must be such that you have both structure, and shade tolerant filler (posts and mesh).
For the structure, using a coppice species might be a way to get yield, and control height, while still using a resilient fast growing species.
We don't know where you are, so species recommendations are difficult.
Paul Cereghino- Stewardship Institute Maritime Temperate Coniferous Rainforest - Mild Wet Winter, Dry Summer
Buy a clumping one and you will not have to work to keep it from spreading too far (lucky you to be in zone 8 there is so many clumping you can grow). Here is a link to the bamboo garden in Oregon, they are far from you and shipping would be expensive but you can use this sight to see what kind of bamboo would best suit you and then look more locally for a source (I paid for shipment to IL because i wanted a specific one).
I send you straight to the price list because most of the information you will thumb through at first is all listed here. You want Zone 8, C for clumping, sounds like you will likely need one which tolorates full sunlight....choose your height. I personally look at the final cane sizes, the smaller the cane the more weeping it is, you want just fence so not much weeping, thicker canes are better (you must look at the individual plant pages for this).
Personally I love the look of weeping bamboos but they are too big for my property .
Not only do deer not eat it but in the end you can harvest the canes and use them for trellises and so much more. You can get more than one variety and then have mature canes of different sizes to use in whatever applications you can think of. Perhaps a really tall thick one of the north side of the property for wind block and big canes.
I have been adding hawthorne and mountain ash and willow in addition to the varieties mentioned above for a very mixed , multi layer perimeter hedgerow that is slowly taking shape, being added to piece meal. The idea of training and interweaving branches to form a more solid barrier to deer or keeping livestock in, is something I hope to try . I hope to be able to obtain food, and coppice or pollard for wood fuel as well making it multifunctional . You can look up the practice of weaving living branches and trunks into structures by searching for 'pleaching' .
From my own experience, deer will browse raspberries and elderberries. That said, they haven't done enough damage to either our raspberry plot or any of our elderberry bushes to warrant fencing them. Blueberries, on the other hand, may need more fencing--although even without fencing our blueberries are still alive and well.
I found a volunteer mulberry at the edge of the garden. It was growing right next to and around/within a weed that was in fully flower. Every time I shook the weed, my clothes would become covered in a yellow pollen and I would sneeze. The mulberry was quite healthy, though. Once I removed the weed, the deer then came and stripped it--there wasn't a green leaf left on it! I think the weed was hiding the mulberry from the deer. The mulberry still seemed to recover well, so we'll see if it grows this summer.
Another mulberry, this time one I planted, hardly grew at all until I fenced it. I guess the foliage is just a touch too tasty for the deer to pass by. At any rate, now that it's been fenced it has recovered from ground level to perhaps about 2 feet tall.
From reading in deer books, the best advice and counsel I might give is Your Mileage Might Vary.
And the LORD God took the man, and put him in the garden of Eden to dress it and to keep it. - Gen 2:15
The two armies met. But instead of battle, they decided to eat some pie and contemplate this tiny ad:
Heat your home with the twigs that naturally fall of the trees in your yard