I forgot to mention, and find that this is a very over looked resource on this forum, if you are not doing a forest garden or if your garden is going to contain many staples like peas, beans, tomatoes, squash and so on, anyone would be well served to check out the plethora of books written on ordinary or organic gardening. Local sources for these would be used book stores, thrift shops and your local library. Permaculture books are excellent for putting together a system, but I find them severely lacking in information on individual plant types and even pest/disease control.
While I do believe that a properly functioning permaculture system will have very few problems with disease and pests, most people don't start with perfect soil/climate and depredations and plagues can discourage the hardiest gardener let alone a person who is new to it. While I would recommend being very careful of many of the traditional remedies (aka poison, so on) (I don't use them), I have found that no information is wasted. The more you know, the better-informed choices you can make. Never take just one source's word for something that sounds weird to you. Books on forests and trees are also good information sources whether you are doing a food forest, or just a guild or two, or merely a sustainable garden. Other information sources on plants include gardening magazines and seed catalogs, local gardeners of all sorts, state agriculture and forestry extensions, local nurseries, public ornamental gardens, private and public forests (walking through them gives a feel for how real forests work), online agricultural information from many colleges and government programs (really, not everything the government is evil. Promise).
I am not just saying this. This is something I do myself, even after nearly thirty years of organic gardening. I have gardened in rich loam fields, sandy compacted small areas, clayey soils, and pots over the course of my gardening adventures. Even if I don't agree with someone/author on methods to results, I can usually find something to learn from them.
I keep most of it in my head because when I'm out in the garden its inconvenient to go searching for information for six hours, but keeping notes and copies of pertinent articles will serve you well and make it easier to find what you are looking for. I am new to "permaculture" as a system, but not to most of the methods that go into permaculture. Some of them are ones I've been using for years. I find that most of what I know about gardening is very useful in a permaculture context, and gives me a wide range of ideas to pull from. Remember, permaculture is a combination of cultures that works well enough to thrive and last with minimum input from you. The cultures being human culture and nature culture.
If you don't like/find useful the local plants, look around for plants that grow in similar climes around the world. For instance, lavender is not native here, but it comes from a very similar region soil/weatherwise in France. (Yes, I know there is more than one type of lavender. Anyway.) Thus lavender thrives quite well here with little or no care at all. Basil, also. Baby it in pots and the stuff keels over or just withers up and dies. Stick it out where it is hot and dry and in the local soil and it's very chirpy. <laugh> Who would have thought?
Also, just because its happy in your area doesn't mean you should grow it. Check FIRST for invasive stats. You don't want to accidentally introduce something like the 'kudzu in Florida' 'water lilies in the Lousiana waterways' 'fish tank weed loose in the Mediterranean' fiascoes. The difference between "very, very happy" and "invasive" in your area is like this: Snapdragons vs. bindweed.
I don't weed or water them and they still happily self seed all over my properties and bloom beautifully. Most of them are also perennial. They do NOT, however, spread over to my neighbors' properties. <-"very, very happy"
Gorgeous, lush foliage, happily climbs up my plants, knocks them over and smothers them. Nearly impossible to eradicate. Whack it off and you can barely tell a month later. Also, happily spreads via root and seed. Roots can travel 25 feet in a year, the longest root ever traced was 2 miles long. The seeds can remain viable for up to 50 years. The plant if flowering when whacked off will set seed from the whacked off section of flowers. <-"invasive"