(This will only address those plants that are truly a perennial and ones that we grow as perennials. There are number of our vegetables that are perennial in their climate, but we grow them as annuals – usually – in our climate. These are treated as annuals elsewhere.)
Perennial food needs to be an integral part of any food system. Perennials provide stability to the food supply, not needing to be planted all the time. They form association with fungi in the soil rather than bacteria using a more diversified soil ecology and greater resilience. Perennials add another delicious component to meals. Annual plants are harder on the gardener because they must be replanted every year. They are harder on the soil because they must grow quickly to full size and produce food within their growing season. A perennial, comparatively speaking, grows to full size and produces food at an almost leisurely pace.
Not being plants you remove from the soil every year allows the ground underneath them to develop long term associations that don't get disrupted every year. These plants are very important to the permaculture gardener as they form major parts of the food forest canopy.
Their importance cannot be minimized. Wes Jackson's Land Institute is working on perennial grains like wheat that will stand year after year in the field and eliminate a lot of the destructive planting and tilling we do annually in order to grow wheat, barley and other cereal crops.
A perennial is any plant that lives for several growing seasons and is not a tree. (A tree is a perennial, but we usually refer to trees as trees and use the word “perennial” to describe any plant that lives for several seasons and is not a tree.) Because they will live for many years, planting them requires more thought and careful consideration. The area must be kept weed free for many of these plants.
We have already been planting garlic, leeks, onions, shallots and onions. There are perennial onions – as follows:
Multipliers – these onions that grow by dividing – you plant one large bulb, and net many smaller bulbs. Shallots and potato onions are in this class. Some gardeners leave the bulbs in the ground to multiply and that probably works best if you have the room. If you don't, things get a little bit more difficult: You lift the bulbs at harvest time, divide them into bulbs you will eat and those you will replant. We have talked about growling shallots from seed or from sets – it's tough to do this kind of planting in SoCal because to get the bulbs to last until it's time to plant them again is tough: they should be stored in a dark and cool spot – something that is a little hard to find in Southern California. These multipliers are best for cooking – they are a little pungent for fresh eating.
Topset onions. Often called Egyptian onions or walking onions, they produce leafy green stalks with small bulblets forming on the top. If bulblets are not harvested, the leaves bend over allowing the onion to drop to the ground and root – so the onions move a little every year, hence the name 'walking onion.' When left in the ground, this onion increases in size. Harvest the bulblets and plant them individually in fall (if bulblets are very small, don't separate them before planting). Mild, tender young leaves (with no bulblets) over the winter can be used like green onions. The small bulblets make tasty pickles. The bulbs normally are left in the ground, but some can be harvested. Since their flavor is very strong, they're best cooked.
Chives – Common chives and garlic chives (sometimes called Chinese chives) grow 12 to 24 inches tall with lavender-pink flowers in spring, and a mild green onion flavor. Simply snip off lengths of leaves with scissors. The Chinese chives with their pronounced garlicky flavor (and aroma) are used in Chinese medicine as one of their healing herbs in addition to being a culinary herb.
Other bulbs we can plant include one of the most expensive spices in the world: Crocus sativus, Saffron. Easy to grow – and easy to misplace! – these crocus bulbs produce the bright yellow/orange stamens that are valued as a spice and also to dye the robes of Buddhist monks.
Often called 'herbacious' perennials, just above the ground are the herbs we commonly use and are so familiar with, they need no introduction: thyme, rosemary, oregano, and others are members of the mint family, including several delicious varieties of mint and are easy to grow. There are oodles of varieties of each, especially of thyme, and each of us will need to find the varieties that float our boat. When it comes to oregano, I've got my love and I proselytize its flavor to any one who will listen: Origanum heracleoticum – Greek oregano, which has a deeper, more complex flavor than the typical Origanum vulgare. As regards thyme, many of the more attractive thymes have added flavors, like lemon-thyme, lime-thyme and even orange-thyme. These are easy to grow in pots and in the ground – they need only ample water and some shade on the hottest days.
Horseradish is similar to herbs in that it is used primarily as a condiment – and, like herbs, it is an easy plant to cultivate, in fact, I've heard folks say it is nigh to impossible to get rid of, although I have gotten rid of it twice – once when I was trying to not get rid of it, so I think in our climate, with our lack of water, we have to keep it watered and shelter it a bit more than you can in other parts of the county. Bury a piece of root in decent soil and you'll see the leaves up shortly. Harvest by digging a bit of the root, peel and clean it, cut in cubes and whiz it in the Cuisinart and mix with white vinegar, adding more vinegar if you need to cut the heat. Do this in a well-ventilated room (outdoors?) as your body will respond as if you were slicing up very potent onions. Unless you dig vigorously you probably wont get out all the roots which will insure you still have horseradish growing. It has a reputation for spreading into nearby beds, so it should be treated with care. Keep it in a pot in the ground if this concerns you, or remain vigilant and count on luck. I cannot imagine a person with one horseradish plant not having enough for an entire block – so if you grow one, share it enthusiastically.
Rhubarb, also called pie plant is another perennial I insist on keeping around. If you like Marie Calender's pies, I'd stay away from eating straight rhubarb pies because they tend towards the tarter side of life and no amount of sugar hides that. Strawberries are a favorite of the wimps who can't take a straight rhubarb pie, like the folks who drink cream in their coffee. I say, if you can't take coffee black, maybe you were born to just drink milk.
Rhubarb was prized as the earliest food folks could get out of the garden after a long cold winter. In the spring that followed that cold winter, the first shoots out of the ground in a garden would be the bright red rhubarb shoots. Called 'pie plant' by many in the mid-west and south, pie and ice cream sauce are about the only uses for rhubarb and for many of those people, rhubarb pie is as much a tradition of spring as pumpkin pie is at Thanksgiving. I love mine with whipped cream or vanilla ice cream or just plain and I’ll two slices, thank you very much.
Most of the rhubarb in Southern California doesn't ever get really red which I think is due to the lack of truly cold weather, but even if the pie looks a little like 'celery pie' it has the same kick as rhubarb. Rhubarb, by the way, is one of the few plants from which we eat only the leaf stem, the petiole, – rhubarb leaves are poisonous.
Asparagus and artichokes are some of the most frequently planted annual herbs in the gardens of California. Artichokes we treat a lot like annuals in our gardens. They, unlike other perennials are easy to move whenever the moma plant dies back, her children, often called pups, can be moved easily from the original site and transplanted elsewhere.
Asparagus is unlike most of the plants we've covered and we'll have to look at it on its own merit. Purchase roots of asparagus in the late fall, early winter. The site must be chosen with some forethought because once placed, asparagus is difficult to relocate. From roots to your first picking will be two years and that picking should be light. Asparagus growers often like to dump aged manure on their asparagus bed every fall. I'm not sure that is necessary, but then I am only in my second year of my second bed so I have harvested very little asparagus... Your long-term asparagus project can come to naught if it gets infested with perennial weeds. Asparagus has very shallow roots which are easily damaged – perennial weeds can quickly ruin an asparagus patch - which is whence went my first patch. Asparagus is NO match for false garlic.
Artichokes are easily grown, the plant that produces chokes this year will die in summer giving rise to baby plants (called pups) which can be left on the plant or cut away and transplanted elsewhere. If you can leave the plants alone for three years, you will soon be giving artichokes away to your neighbors or making artichoke heart stew! Allowing some the last chokes to flower is a long lived tradition I adhere to because it elicits so many cries of joy.
Strawberries are much prized and if done correctly can provide a gardener with years of sweet deliciousness in season. They must be well-mulched, and attention to have mulch that doesn't also serve as a haven for snails and slugs must be given. Slugs and snails will decimate your strawberries almost as fast as children – although, children will eat the whole berry while a slug or snail will at least only take part of the berry allowing you to trim off the slug part and have the rest for yourself. Plan your strawberry patch with some forethought because it will be there for a long time, if you're lucky.
Blueberries, Vaccinium sp. There are several blueberry varieties that will produce nice berries in Southern California. They take about three years to get up to snuff – but they are easy enough, and once, established make for some great eating! Emerald, Jewell, Misty and Sunshine Blue are varieties suggested – I have only experience with Misty and I love it!
California Native plant specialists will point to Ribes aureum as being a native edible species. They are correct in the most strict sense of the word 'edible.' I would not want to be forced to a diet in which the starring role was played by the Golden Currant. About 30 of them comprise a decent mouthful and it is time consuming at the least to collect several mouthfuls off one plant. It is a good berry, but not amazing. It is however, the only Ribes species that will grow here in southern California – all those black current preserves are there just to tempt you. Remember, we can grow so much more than they can, we ought not covet that little they can grow without us.
Brambles - all the cane berries are called 'brambles.' They are almost all weedy and difficult to control, spreading by underground runners (that have thorns too!) but if you have the space and cannot do without them, they are easy to grow. Raspberries, Blackberries. There is a thornless white raspberry that is worth looking into if this sort of thing cranks your tractor.
Vines – grapes, kiwis, passion fruit are some of the more popular vines we grow for food. Especially if you have some fence (sturdy fence) that you can grow them on.
Apples, peaches, apricots, plums, nectarines, figs, pomegranates and persimmons all grow here as easy as it gets. The choice of variety is most important because many of these fruits need a set amount of chill time in order to produce fruit. Neither true cherries or pears do well in our coastal clime, although some of you further inland might find a pear or two that you can grow – cherries require the most chilling of all stone fruits.
First off, let's tackle the concept of 'chill hours.' Every fruit that need some cold in order to set fruit is said to need 'chill hours.' This measurement of how much cold a given variety needs is not well-understood and the amount of hours that given variety needs fluctuates, sometimes wildly, which let one know that this is not a hard science in the same way as gravity.
The easiest method is called The 45-degree-Fahrenheit-and-under model. Simply calculate a given variety's available chill hours by estimating how many hours it will spend in temperatures of 45 º F and under. One hour of time is equal to one chill hour. During the winter, you can add up the chill hourscumulatively, taking away one hour for every hour the temperature rises above 60º F. If you see an apple listed at 500 chill hours (like Fuji), and you live on the coast, cross if off your list.
Apples we can grow include, Anna, Ein Schiemer (both Israeli varieties that were bred for their conditions that are very similar to ours) and my favorite, Dorsett Golden, named 'golden' for medals and not for the color of the skin. All of these apples get apple scab which, though not fatal is still a problem. If you are inland and have more chill hours, Fuji could be one of your choices.
Apricots include Sunkist, which I think is the best apricot I've ever, ever tasted although Blenheim gets all the press. I don't know why.
Nectarines – our list includes: Snow Queen and Arctic Star.
Our peach selection is likewise slender, and while there are others, have to admit, Strawberry Free and Red Baron top my list.
Figs, mulberries, pomegranates and persimmons are not too picky about chill hours and we can grow almost all of them. These are all delicious fruits and can be quite productive blessing one with loads of fruit that can be somewhat overwhelming – we should all have this problem!
I wish I could get a pawpaw to grow here. This is a fruit with a texture like a custard and is endemic to the area around southern Ohio.
A number of productive almond varieties will produce lovely crops in Los Angeles. I was given two varieties a couple of years ago, one was tagged with the name 'Nonpariel' which means, non-parallel. The other, not being tagged, was promptly named 'Pariel.' I still don't know it's name! Most almonds require two trees (of different parentage) to cross-pollinate in order to crop decently.
We are not cold enough for filberts,pistachios or walnuts but we can grow pecans – I don't have any experience with any pecans as I only eat pecans a couple of times a year.
I would encourage anyone with any amount of land to grow a native oak tree. The acorns are edible and there is evidence that the presence of acorns played a significant role in humans becoming agricultural. The early agricultural communities could settle in one place and experiment in agriculture because they could pick all the food they needed from the local oak trees. Our California oak trees produce edible acorns that can be prepared for eating. Our own Valley Oak, Quercus lobata is one of the most edible of the species. While they might not be your first choice for food, the acorns can serve as a back up source and in the meantime, oaks provide habitat and food for a good number of Native Californian species.