I've ordered these roughly by theoretical future performance and usefulness to us in our current location.
Garlic, Elephant Garlic, and Shallots (INULIN ROOTS)
Edibility: Roots and greens raw or cooked
Growth: Clumpers to about 2-4' tall. Foliage grows from late fall or early winter, then dies down with summer drought.
Harvest: Roots dug in summer. Normally one harvests everything and stores the roots for eating. When we miss plants, they seem to perennialize, but we've only harvested greens from them, and haven't tried to work out an ongoing perennial root harvest.
Culture: Most productive in full sun, but we've had success growing them under trees where they get shade from spring til summer. Adapted to summer drought.
Yield: Not sure of pounds per square feet. Supposedly garlic and elephant garlic roots contain more than 600 calories per pound! Unfortunately, that comes in the form of inulin, and of course one can only eat so much garlic per day.
Potato - Solanum tuberosumWe haven't actually grown a lot of potatoes. I have an ideological bias against the carbohydrate-heavy, high glycemic load potatoes provide, since I'm aiming for a paleodiet. Plus I have my doubts as to the long-term yield of potatoes once certified virus-free slips can't be imported.
Edibility: Root, cooked only.
Growth: Clumping, to about 2' tall and up to 3-4' wide.
Harvest: Available from early summer through fall. Seem to store OK in the ground, though normally people harvest the full crop and store it for winter consumption.
Culture: Seems to do OK in heavy shade, though normally grown in sun. I think it needs some watering, but I haven't paid proper attention.
Some people grow potatoes as true perennials, allowing the plants to continue in place while harvesting some of the roots from time to time.
Yield: Can certainly give very high yields, both in pounds and in calories per square foot. We've had moderate yields of about .5 pounds per square foot, without putting much care into it.
Cinnamon Vine - Dioscorea batatasAlthough people can and do harvest the actual roots for eating, it takes a lot of digging to access the deep brittle taproots. I plan to use them in the future for their aerial bulbils, rather than the roots.
Edibility: Root and bulbils cooked. Root comes very close in taste and texture to potatoes.
Growth: Deciduous herbaceous vine. Gets maybe 7-8' tall in a growing season here.
Harvest: Bulbils form in summer, and it seems best to lay a tarp under them to catch them as they fall.
Culture: Provide some sort of vertical support in full sun.
Camas - Camassia quamash, leichtlinii, & cusickii (INULIN ROOT)Staple root crop for northwest native americans. We're still getting our patches going (fairly slow to propagate and spread themselves). See also my report-back on foraging camas.
Edibility: Root cooked. Unlike many inulin roots, these taste very gummy and unpleasantly starchy unless fully cooked (ie, 9 hours in a pressure cooker) at which point they taste like caramel candy.
Growth: Spring ephemeral bulbs to 1-3' tall depending on species. Slowly spreading patches.
Harvest: Dig during dormant time from summer til late winter. Harvest the largest bulbs and leave behind the smaller ones.
Culture: These do fine in winter wet including standing water. Presumably best with full sun access during main growing season, though may work well under late-leafing trees. Adapted to summer drought.
Canna lily - Canna indicaWe killed one plant a few years ago, I believe because we grew it in standing water over the winter. (Thanks to the fellow (Matthew??) who mailed me the starts from the east coast!) One year ago we planted a new division from a patch doing well in this climate.
Edibility: Root cooked. Mild starchy taste.
Growth: Slowly spreading clumper to about 3-4'?
Harvest: Harvest in fall or winter after foliage dies down (with the first frost??)
Culture: Likes moist soil (but apparently not full-on standing water!). We placed our start in our main garden area, which got watered once or twice a week through the dry summer.
Yield: Our division definitely made substantial roots this year, and I see potential for good yields.
Parsnip - Pastinaca sativaWe've been trying to get self-seeding patches going, but we haven't seen very good growth from seeds. Perhaps too much slug pressure? Or too much other plant competition with not enough soil disturbance from us?
Edibility: Root raw or cooked.
Growth: Biennial clumper to 3' tall. Seems capable of going dormant during summer dry season and resuming growth with fall rains.
Harvest: Perhaps any time of year?? Considered sweetest after some autumn frosts.
Culture: Full sun, disturbed soil. Supplemental watering probably helps a lot.
Grape hyacinth - Muscari neglectum
Edibility: Roots cooked. I find them very bitter and tolerable only in small amounts mixed with other food. Tulsi detects only mild bitterness, so can eat more of them.
Growth: Bulb spreading fairly quickly. In growth from fall or mid winter through summer, dying down with the drought.
Harvest: Presumably the dormant season, from summer til fall or winter.
Culture: I assume full sun is best. Adapted to summer drought.
Chinese artichoke - Stachys affinis
Edibility: Root raw or cooked, supposedly crispy and nice nutty flavor.
Growth: Running herbaceous mint to 3' tall.
Harvest: In the fall? You'll always miss some, so the plant will grow back year after year.
Culture: Sunny position with moist soil supposedly ideal.
Yield: Plants for a Future database says about .25 pounds per square foot.
Earth chestnut - Bunium bulbocastanum
Edibility: Root raw or cooked (though cooking doesn't seem to add anything to the taste or texture). The best tasting root I've ever had, even a little tastier than skirret! Leaves raw or cooked, available through the winter. Seed raw or cooked as a cumin substitute.
Growth: Slowly spreading clumper to about 18" tall. Takes a while to get established, but our patch has finally formed a dense carpet after 2-3 years of growth from three original small divisions.
Harvest: We've only harvested once, last December, by digging under a dense clump and flipping it over, then removing the marble-sized roots thus exposed at the top of the flipped-over-clump. After harvesting many or most of the roots, I flipped the clump back over, and it seems to have recovered just fine.
Culture: Could possibly be used as a ground cover, though very slow to establish. We have ours in full sun, and give them some water in the summer along with the rest of the front yard. (Maybe once or twice a week.)
Yield: Probably very small, since the roots are so small. But perhaps an established clump can yield good numbers on an ongoing basis. Probably lots of potential for breeding work!
Miscellaneous spring ephemerals - Triteleia, Brodiaea, Dichelostemma, Erythronium (INULIN ROOT?), etcI've tried to start many of these from seeds with very low success (I suspect massacres by slugs), so haven't gained much personal experience. But I think they have potential as an understory crop.
Edibility: Roots cooked. Some may have edible leaves cooked.
Growth: Spring ephemeral bulbs, growing from late winter til summer.
Harvest: During dormant season. Harvest largest bulbs, and leave smaller bulbs to continue growing.
Culture: Suitable as understories to late-leafing shrubs and trees. Adapted to summer drought.
Woodland chervil - Anthriscus sylvestrisSee also my crop summary
Edibility: Root cooked (and raw??). Leaves raw or cooked. Maybe seeds raw or cooked?
Growth: Clumping biennial (or perennial?) to 4' tall. Ours stayed in leaf through this past winter. They normally set seed in late spring and maybe die off after that?
Harvest: Dig roots maybe year round??
Culture: Doing fine in full shade with almost no supplemental water.
Sweet cicely - Myrrhis odorata
Edibility: Leaves raw or cooked, usually with sweet anise flavor. Immature seeds raw, tasting like licorice jelly beans. Root raw or cooked, supposedly with the same flavor, though the one older root I've tried didn't taste like much.
Growth: Clumper to about 3' x 3'. May keep a few leaves over the winter, but mostly grows from early spring til hard frost.
Harvest: Probably best during winter? Also possibility of harvesting excess seedlings in summer?
Culture: Full sun to part shade. Probably requires some supplemental water in summer.
Lovage - Levisticum officinale
Edibility: Leaves raw or cooked, a celery substitute. Seed raw or cooked (haven't tried this.) Root cooked; I don't remember it tasting like anything exciting when I tried it once.
Growth: Clumping to 6' tall.
Harvest: Not sure when to harvest the root for best results.
Culture: Full sun to full shade. Tolerates drought just fine.
Orpine - Sedum telephiumMostly interested in this as a potential ecoroof root crop. We've just begun to grow it, so I don't know much about the root harvest.
Edibility: Leaves raw. Root cooked.
Culture: Supposedly full sun to full shade. Definitely drought tolerant.
Edibility: Leaves cooked (I think they tasted OK the time or two I tried them.) Roots cooked, but I've never really liked them when I've tried them. Not sure why.
Growth: Spring ephemeral bulbs, spreading at a medium rate. Die down with summer drought.
Harvest: Probably best during dormant season, from summer til late winter.
Culture: Full sun probably best during growing season? Adapted to summer drought.