Tuesday, June 21, 2011

Perennial polyculture: New Designs

This is part three of a three part series on perennial polycultures:

  1. Designs: a five year review
  2. Species profiles
  3. New designs


Following the massive failure of our original polyculture designs (see part one), I spent some time this past winter utilizing my hard-won knowledge of our successful perennials to try again. I didn't design anything for greens, since we have more than enough already established and coexisting quite nicely. I focused instead on root crops, which have proved more difficult to just plant here and there for a few reasons (not all reasons apply to all root crops):
  • Soil disturbance damages adjacent perennials or roots of woody plants
  • I lose track of where I planted odd plants after they've gone dormant, so can't harvest the roots
  • Roots (especially those starting from small tubers or seeds) get outcompeted by other perennials
In this post I'll present the polycultures we're trying this year. I'll also mention a few other ideas I've had but haven't tried to implement. Refer to part two of this series, species profiles, for individual plant characteristics, presented in roughly the same order in which they appear in polycultures in this post.



Garlic & Skirret

Garlic & skirret in foreground
volunteer burdock & more skirret in background
This bicrop makes use of different time niches with these two root crops. I planted garlic at about 9" between bulbs, with skirret between with 9" spacing to other skirrets and 4.5" to neighboring garlics. Garlic grows through the winter and has died down in early summer by the time skirret has gotten big enough to begin competing for light. Garlic bulbs should lift out easily without disturbing the skirret, and skirret's drought tolerance allows for non-irrigation of the garlic while the bulbs dry down.

This patch could be replanted in the same place year after year by harvesting all the skirret in September and October, then replanting garlic cloves and skirret crowns. Or move the garlic to a new patch and harvest the skirret as needed through the winter, replanting the skirret crowns into that new patch as they become available.

Skirret, Day Neutral Strawberry, & Oniony Thing

This patch combines the need to thin strawberry plants with the need to thoroughly dig up skirret roots. It works because you can leave skirret in the ground for two years before harvesting, and because we have day neutral strawberries which should be thinned in late fall or over the winter. (June bearing strawberries should be thinned after they bear their crop in mid summer). I planted four rows 15" apart in a 5' bed, with skirret and strawberries alternating in their rows every 8". (16" between strawberries, 16" between skirrets, 8" from a skirret to the closest strawberry.)

I planted some sort of evergreen oniony thing between the rows to have some winter growth of its edible leaves. Originally I planned for the ongoing disturbance of the skirret & strawberries to prevent the oniony thing from getting swamped out. But as of mid June, the oniony thing is dominating the area and I'm aggressively harvesting their leaves to open up space for the strawberry and skirret!

This fall I would harvest skirret from two of the four rows (rows 1 and 3), replanting skirret crown divisions after harvest. This will wipe out most or all of the strawberries in those two rows. Next year the strawberries left in the undisturbed rows 2 and 4 will recolonize rows 1 and 3, while the skirrets in rows 2 and 4 grow for a second year.

Next fall I would harvest the skirret in rows 2 and 4, wiping out those strawberries and replanting the skirret crowns. Then follow the same pattern in the future, harvesting two rows each year, such that each row is harvested every other year. This should keep the strawberries from crowding themselves out, as a natural byproduct of thoroughly digging the soil to harvest the skirret. I would adjust the size of the skirret crown divisions in future years to integrate well with the strawberry growth rate--smaller if the skirret is outcompeting the strawberries, or larger if the skirret is getting swamped.

Skirret, Oca, & Potato

This patch uses time niches to some effect, though it doesn't have any winter evergreens.

Oca and potatoes alternate in rows with 16" from one oca to the next potato, (32" from oca to oca and 32" from potato to potato.) I spaced two rows 30" apart in a 5' bed. I then planted one row of skirret halfway between the oca/potato rows, with skirret on 12" spacing within its row.

Skirret and potatoes grow vigorously early in the season, with oca putting on growth more slowly. We'll harvest potatoes July through September, with skirret still providing shade for the oca in the heat of the summer. With the cooler cloudier weather in September, the oca vegetation should quickly fill out to use up the space left behind by the potatoes. We'll dig all the oca tubers out after the first frost, and harvest skirret as needed through the winter. We can either reimplement the same polyculture in the same bed, or rotate it to other beds to prevent disease problems with the potatoes.

Oca, Asiatic Lily, & Yellow Asphodel

Confusing mess w/unplanned strawberry etc

Utilizes different time and height niches. These are planted in an understory wedge to the north of a young persimmon. At 6' tall the persimmon casts minor shade. Oca is planted on 30" centers with asphodel surrounding it on 10" centers. One lily is planted in the center of each oca "triangle". I don't have enough asphodel propagated yet, but eventually their density could be increased to about 6" between plants.

Asphodel grows from fall through winter til early summer, making its roots available for harvest while the oca is still small. The oca and asphodel provide ground cover for the lily, which grows above them. Harvest all oca after first frost, and harvest lilies as needed through the winter.

Lilies and asphodels can be harvested with fairly minor soil disturbance, so the main conflict might be the effects of oca harvest on the asphodel roots with their new-ish growth going into winter.

We planted this polyculture into an area somewhat invaded by strawberries, and with remnant camassia and weeds including dandelion & popweed. We may have trouble with the strawberries especially, since we don't have a strong ground cover or weed excluding element.

Yellow Asphodel, Good King Henry, & Violet

Utilizes height & time niches. Violet should be an evergreen (we're using Viola odorata) for permanent low ground cover and winter greens, with the yellow asphodel and good king henry (GKH) growing up through it. The GKH begins growing late in the spring, but the other two plants should help suppress early weeds, and the asphodel will then die down in summer for the GKH to fill out further. We should be able to harvest the asphodel roots in the summer with minimal disturbance to the GKH.

I planted GKH about 2' apart, and would eventually like to have asphodel at 6-8" spacing filling all the interior area. We don't have enough asphodel plants yet for full density, so they're more sporadic for now. The violets will fill in wherever they find gaps.

Jerusalem Artichoke, Mashua or Groundnut, & Chinese Artichoke or Creeping Bellflower

Jerusalem artichokes with small
chinese artichoke underneath
This polyculture has a core structure but multiple possible plants to plug into the different niches. It mimics the well known three sisters guild of corn, beans and squash, which Eric Toensmeier has proposed morphing into the perennial guild of jerusalem artichoke, groundnut, and chinese artichoke. This polyculture makes use of above ground space niches, but not of time niches, since these root crops require heavy disturbance for harvest in fall through early spring. With the possible exception of the creeping bellflower, they should all benefit from the regular ground disturbance and loosening of the soil.

We're retaining jerusalem artichoke as the vertical element; we had an existing 100 square foot patch. However, we've never had much success growing ground nuts here, so we only planted 3 or 4 which survived from last year, instead mostly planting mashua on 3' centers as the vining element to climb the jerusalem artichokes. We can easily supply nitrogen via our urine so we don't require the leguminous groundnut for nitrogen fixation.

For the ground cover layer, we're trying about half a dozen fast-spreading chinese artichoke in half the patch, with creeping bellflower 1-2' apart as another vigorous, shade tolerant root crop in the rest of the area.

Our patch gave us about 100 pounds of jerusalem artichokes last year (1 pound per square foot). It makes sense to knock back the jerusalem artichoke production a bit in favor of more root diversity, and hopefully the total yield of roots will increase while we're at it.

Brief Mention

Oca & Tomatillo / Ground Cherry

Ocas & tomatillo at bottom
tree collard and mashua at top not part of guild

Inspired by oca-testbed's oca & tomato bi-crops, I've planted 3 ocas, 2 annual ground cherries, and 2 tomatillos with 10" between each oca and its neighboring ground cherry or tomatillo (20" from one ground cherry or tomatillo to the next).

Squash & yacon

I planted some squash seeds at 6' centers and yacon halfway between at the 3' mark. The yacon should grow tall enough to hold its own by the time the squash reaches it, to share the space niche a bit. It may work somewhat as a time niche, too, as squash often dies back in early to mid fall with powdery mildew, while the yacon can keep growing until frosts kill it.

Not Implementing

Oca & squash

We created an accidental time niche bicrop a few years ago when a squash covered up some oca for most of the summer, but started dying back with powdery mildew in early fall, allowing the oca to explode in growth and fill out the space. We didn't get much of an oca yield--but I wasn't experienced enough at that time to pay close attention to frost and harvesting all the oca promptly. So maybe we got some roots but they rotted? Or maybe the squash didn't allow the oca to grow well enough to produce roots? I'd like to try this again with squash on 6' centers and two or three ocas at the 3' point in between. Or try combining it with the squash & yacon polyculture, with the squash and yacons spaced further apart to allow oca some breathing room between the larger plants. (See oca-testbed's polyculture mound of yacon, oca, and chinese artichoke.)

June bearing strawberry & summer root crop

I've tried to design a polyculture which combines digging some root crop with the need to thin June bearing strawberries in late summer, after they've finished cropping for the year. I've had a much harder time with this than with day neutral strawberries (see my polyculture with skirret above), since very few root crops can be harvested in the summertime after two years of growth to allow the alternating row harvest method. Strawberries fill out quite well by mid spring, creating a lot of competition for anything shorter than they are, limiting the ability to sow seeds or plant small divisions at the beginning of the growing season. Further, the root crop can't be allowed to outcompete the strawberries too badly -- we have some burdock in our patch, and we have to keep harvesting the huge leaves (we do eat the leaf stalks) or the strawberries get totally covered up!

Spring ephemeral bulbs such as Camassia, Triteleia, Brodiaea, or Erythronium might work for the row harvest method, especially if you establish a solid patch first, then add strawberries later. Or instead of harvesting a full row at at time, you could do a distributed harvest of the thickest clumps of bulbs, disturbing patches of strawberries here and there while eating the largest ephemeral bulbs and leaving the small ones behind to regrow quickly the following spring. Or try root crops whose seeds can germinate in the autumn, overwinter as a small plant, and grow quickly in spring: black salsify (Scorzonera hispanica) or dandelions for full row harvest after 1.5 years, or black salsify, dandelions, or parsnips for distributed patch harvest the summer after they've been sown.

Monday, June 06, 2011

Perennial polyculture species profiles

This is part two of a three part series on perennial polycultures:

  1. Designs: a five year review
  2. Species profiles
  3. New designs


In Perennial polyculture designs, I mentioned inadequate knowledge of plants as one barrier to successful implementation of my designs. We've now gained enough knowledge of a few perennial plants to try again. With this mouthful of a title, I give the relevant design characteristics of perennial vegetables we're trying in polycultures this year. Unless otherwise noted, I consider these plants primarily root crops, though some have secondary uses like edible flowers or leaves. By the way, for more information on many of these unusual root crops, including some polyculture experiments, see:
  • Oca testbed - nice details on tomato & oca bicrops, plus lots more on oca and some on other roots
  • Radix Root Crop Research and Ruminations - pioneering work with many roots I haven't tracked down or in some cases even heard of before
  • Obligatory link to Plants for a Future database.

Species characteristics

Garlic (Allium sativum)

  • Harvest time: July or August
  • Harvest process: Lift all bulbs, which doesn't require much soil disturbance. Store in cool dark place.
  • Planting process: Plant cloves in October or November, which doesn't disturb soil, but cloves shouldn't be disturbed by other digging after being planted.
  • Generally doesn't require any watering, and in fact shouldn't receive water in July so the bulbs can dry out for long term storage.
  • Vegetative growth: small amount of leaves over the winter, growing more actively in spring. Die back in July with the summer drought.

Skirret (Sium sisarum)

  • Harvest time: October through April. Stores in the ground all winter.
  • Harvest year: can harvest after one year of growth, or leave in the ground for multiple years for more and larger roots, which seem less prone to having a woody core.
  • Harvest process: Dig large chunk of soil from around plant (up to 2.5' diameter with older plants), pull out crown. Cut off roots, optionally divide and replant crown. Can be difficult to find in late winter after stalks have rotted away.
  • Drought & shade tolerant
  • Vegetative growth: Appears mid-season (April), grows fairly quickly to 3-5' tall (depending on age of plant), and dies down in early fall (October). Dense, casting heavy shade.

Garden strawberry (Fragaria x ananassa)

  • Use: berries
  • Harvest time: summer through fall
  • Best with full sun and adequate water through growing season.
  • Benefits from thinning (following the annual harvest for June bearing varieties, and in the winter for day neutral varieties)
  • Vegetative growth: semi evergreen to 1' high, spreading quickly from runners

Potato (Solanum tuberosum)

We haven't actually grown potatoes very much, but my understanding so far:
  • Harvest time: June onwards. Can probably store in the ground through the winter?
  • Harvest process: Seems to need a fairly thorough excavation of the soil, especially to find all the roots. We had many potatoes return this year from last year's plantings, so this seems to have potential as an overwintering perennial. Disease buildup normally demands crop rotation.
  • Supposedly fairly drought and shade tolerant.
  • Vegetative growth: Starts growing in late March or April. Reaches 3' wide? Yields supposed to improve with hilling up soil onto the lower stem.

Oca (Oxalis tuberosa)

  • Harvest time: after the first light frost(s) kill the foliage, but before hard freezes damage the tubers, which often dwell close to the soil surface.
  • Harvest process: Dig out all the roots, generally concentrated at the center, though some may form where foliage touches the soil. Store in cool dark place for the winter, replanting some tubers in spring. In mild climates, tubers missed at harvest time may resprout on their own in spring.
  • Appreciates some shade during heat of the summer, but may not tolerate too heavy competition. We tried it as a ground cover amongst other plants one year, and they swamped it out with very little root yield.
  • Vegetative growth: Leafs out in April or May, generally low growing to about 1', though can clamber up other plants if it needs to gain access to sunlight. Doesn't put on much growth until September, when cooler cloudier weather kicks in, at which time the foliage explodes to 3-4' wide.

Asiatic lily (Lilum sp)

  • Harvest time: Late fall through early spring.
  • Harvest method: Compact bulb, so fairly easy to harvest with minimal soil disturbance. Leave large offsets behind to regrow. Can be difficult to find in late winter after top stalks have rotted away.
  • Like their feet in shade and top growth in sun, thus well suited to combination with a low ground cover.
  • Vegetative growth: comes up in early to mid spring, grows to 3-4' tall, and dies down in fall.

Yellow asphodel (Asphodeline lutea)

  • Harvest time: Can definitely harvest in the summer, and I think we can dig roots year round.
  • Harvest process: Medium soil disturbance, concentrated around center of each plant. The plants make numerous offsets, and each plant has multiple thin roots. So you can harvest some entire plants and leave/replant others, or cut some of the roots off of each plant and replant them all for slower/less vigorous regrowth. Not sure yet of the best method.
  • I think it prefers full sun, and probably doesn't need any irrigation.
  • Vegetative growth: somewhat sparse, to about 1.5' tall on flowerless plants, or 3' tall on single flower spike. Doesn't seem to compete all that well with other plants, so may do best with a low growing ground cover for weed exclusion. From the Mediterranean, so well adapted to our summer drought by dying down in mid summer and coming back with fall rains, staying green through the winter.

Good King Henry (Chenopodium bonus-henricus)

  • Uses: leaf crop (spinach substitute) and seed crop (used like quinoa, though smaller).
  • Harvest time: leaves throughout season. Seeds over a period of about three months, July through September.
  • Harvest process: seeds require periodic picking every week or two as different seed stalks ripen at different times.
  • Somewhat shade & drought tolerant, though I assume for optimum seed production we should give it full sun and summer water.
  • Vegetative growth: comes up in late spring, reaching about 1.5' tall and perhaps a bit wider. In our back yard where chickens roam, we have a fairly pure stand of GKH and it does fine. In our front yard, (because chickens aren't eliminating the other plants? or because the GKH hasn't dominated the root zone yet?) the GKH gets crowded out by the early spring growth of nipplewort (Lapsana communis), lemon balm (Melissa officinalis), and wood avens (Geum urbanum) and I've had to weed the bed this year. Like the yellow asphodel, would probably benefit from a low growing weed suppressing ground cover.

Jerusalem artichoke / Sunchoke (Helianthus tuberosus)

  • Harvest time: October through April
  • Harvest process: Major soil disturbance. Will always miss some roots so that it will regrow the next year. Can be difficult to find roots in late winter after stalks have rotted.
  • Drought and shade tolerant
  • Vegetative growth: appears mid spring, reaches 8+' tall. Dies off in late fall.

Mashua (Tropaeolum tuberosum)

  • Harvest time: In theory, should harvest after the first light frost(s) kill the foliage, but before hard freezes damage the tubers. Roots seem much hardier than oca and yacon, though, such that they might store OK in the ground through the winter.
  • Harvest process: Fairly thorough excavation to dig all roots, storing in cool dark place for the winter. We usually miss some of the roots so that it regrows the next year.
  • Appreciates some shade during heat of the summer
  • Vegetative growth: Vining to at least 10' tall, climbing other vegetation. Appears in mid spring and grows at a fairly steady rate until frosts.

Groundnut (Apios americana)

(c) 2004 Steve Baskauf
We haven't had much success with this plant, but we haven't totally given up on it yet..
  • Harvest time: dormant season, late fall? through late spring?
  • Harvest method: Extensive excavation required. Leave some tubers behind to regrow.
  • Fixes nitrogen
  • Vegetative growth: vining, scrambling up surrounding vegetation. In our climate, appears around June and disappears in September or October.

Chinese artichoke (Stachys affinis)

We've only grown these for one year, so I base this mostly on the literature:
  • Harvest time: Dormant season (fall through early spring)
  • Harvest process: Probably requires major soil disturbance, especially since I don't think dead plants leave woody stalks behind to mark their spots. Will regrow in spring from tubers you missed.
  • Moderate moisture requirements?
  • Vegetative growth: appears in early or mid spring, gets about 1' to 1.5' tall, runs quickly (mint family) and forms good ground cover. Not sure exactly when it dies down.

Creeping bellflower (Campanula rapunculoides)

  • Harvest time: I think we can get usable roots year round.
  • Harvest process: Fairly major soil disturbance. Need to dig towards the center of the clump to find usable roots. I suspect it will keep regrowing vigorously after each harvest with no need to deliberately leave roots behind.
  • Very shade tolerant, and competes well with other vegetation.
  • Vegetative growth: Leaves appear in early spring and make a good source of greens while others are somewhat scarce. Plant reaches about 3' tall and runs vigorously. I think that without irrigation it responds to our summer drought by going somewhat dormant, resuming growth in the fall before dying back for good over the winter.

Thursday, June 02, 2011

Perennial polyculture designs: five year review

This is part one of a three part series on perennial polycultures:

  1. Designs: a five year review
  2. Species profiles
  3. New designs


When we first moved to this site in 2006, I designed, on paper, elaborate perennial polycultures for tree understories. In each guild I included at least one plant to perform the main "food forest" functions: nitrogen fixation, nutrient accumulation (generally deep taprooted plants), beneficial insect feeding (plants in the carrot and sunflower families), aromatic pest confusing (onion family and mint family with their strong odors to throw off pests trying to find their preferred plant), spring ephemeral for early season nutrient cycling, ground cover, and foot tolerant path cover. I also wanted all the plants to have some direct human use, whether as food or medicine. And I tried to minimize inter-plant competition by matching vigorous runners with taller clumpers, plus designing for a combination of taprooted, fibrous, and flat rooted plants. I placed plants under each tree according to their sun requirements, designing for a fairly mature tree canopy casting significant shade (with some thought to the transition period of full sun in the early years.) And I matched guilds to tree root patterns, so that a taprooted tree would mostly have shallow rooted plants under it, and vice versa. Example polyculture design (1 MB PDF) I can't call these designs complete failures. The exercise of working them out helped me think through all the factors involved, and helped me learn the on-paper characteristics of many interesting perennial plants. I'm glad I did it. However, I never successfully implemented a single design, for several reasons.

Reasons for failure

Plant (Un)Availability

Our Process

To create my list of desired species, I diligently went through every entry in the species table at the end of Volume II of Edible Forest Gardens by Dave Jacke and Eric Toensmeier, plus all the species rated 4 or 5 in the Plants for a Future database. I added a few plants from books like Simon Hickmott's Growing Unusual Vegetables, local edible plant nursery catalogs, and odd mentions here and there. I came up with a great list of about 175 potential guild plants. I worked from the list to create my polycultures, then began tracking down the plants to implement the guilds. I hadn't anticipated the difficulty I would have locating the plants, even in the form of seeds which posed their own propagation learning curve. Over the last five years I've ordered hundreds of species of seeds from dozens of seed companies, spending hours researching and combing through plant catalogs. (My two most useful plant source search engines: Dave's Garden Plant Scout and UMN's Plant Information Online.) I managed to track down 90-95% of the species on my original list, though I kept adding more species of interest over the years, so that I still have dozens of species I would trial here if we were staying in this bioregion. Of the species I could find, only about 50% grew successfully. The rest never germinated, succumbed to slugs, got outcompeted by other plants, rotted from winter moisture, died with drought, or disappeared while we weren't watching. With the skills I've gained over the years in seed starting and with willingness to provide some extra babying to the most interesting species, I'd probably re-try another dozen or two of those failed species if we were staying here longer.


The long, drawn out process of tracking down seeds over several years, starting them up, waiting for them to get large enough to plant out, and having many of the attempts fail to produce a viable plant meant we never had all the planned species for a given polyculture at once. So my on-paper designs had to adjust to accomodate what I actually had available, with additions over the years as I successfully grew out new plants to incorporate. I still tried to make additions based on the original factors of guild function, top growth, and root patterns, but inevitably my incremental plantings lacked the full integration of my theoretical designs.

Inadequate Knowledge of Plants

I gathered as much information as I could on plant habits, culture requirements, and uses before designing my initial polycultures. But the books can only give so much detail on the intricacies of a living organism's life cycle, don't always accurately describe a plant's response to our particular climate and site, and certainly can't tell us whether we'll actually like eating the plant, or which part(s) we'll value the most, or what time of year we find the plant most useful.


Size, life cycle, & harvest methods: Skirret

The literature led me to believe that skirret (Sium sisarum) would grow to 3' tall by 1-2' wide. We've found that, on our site, that accurately describes a first year plant with its flowers, but older plants easily reach 5' tall and 3' wide. In mid-summer, after our typical weeks without rain, the first rainstorm or the first irrigation via our sprinkler weighs the foliage down so much that the whole plant flops right over. So my skirret placed carefully 1.5' from the edges of paths fell into them and created a maintenance problem. Other subtle details of skirret's life cycle and harvest methods affect how it integrates with other plants:
  • The roots radiate outwards in all directions from the central crown, necessitating a thorough excavation of the soil to find all the roots. So as opposed to something like garlic with a bulb easy to pull out without soil disturbance, skirret does not work well under trees and shrubs, nor next to perennial greens. Instead, it needs to integrate with other root crops or self seeding annuals.
  • The foliage dies down relatively early in the autumn, before the first frosts, allowing early harvest and potential cover crops or garlic plantings. Many of the roots we grow can't be harvested until November or later, so this timing makes a big difference in polycultures or time niche planning.
  • Skirret top stalks stay visible for several months into the winter, but by late winter or early spring they've rotted off, making it difficult to find the root locations. So it works best to have predictable locations for the skirret, or situations where it doesn't matter if some plants regrow in the spring where we missed harvesting.

Life cycle & harvest methods: Creeping bellflower

Creeping bellflower (Campanula rapunculoides) volunteered in our yard. I identified it, looked it up, discovered it's considered invasive in gardens as it runs rapidly but that the roots are edible, and devised a plan of allowing it to grow in place, with periodic harvesting of the roots from the edges to keep it in check.

Several times I dug up the edges to find the roots, but never found anything larger than spaghetti, tough and fibrous with nothing that seemed actually edible. I wondered whether this was a famine food, or if I had defective plants, or what. Finally I happened to dig into the center of my neighbor's patch of the plant, and discovered numerous sizable roots up to 3/4" diameter and 1' or longer! So apparently the plant only makes large roots over time, and my plan to harvest young roots from the edges won't work.

Parts used: Scorzonera & Dandelion

We originally planted scorzonera (Scorzonera hispanica) as a root crop. Soon thereafter, we learned that the leaves make an excellent lettuce substitute, so the plant became primarily a perennial green, with self-seeded plants as a bonus root crop. So rather than growing scorzonera in frequently disturbed soil in zone 2, we grow it in an undisturbed zone 1 bed. Conversely, we originally considered dandelion (Taraxacum officinale) just a leaf crop, best used during early spring then weeded out. Last year I discovered the roots make an excellent vegetable in their own right, providing a low maintenance root crop in the summer. So now we let the dandelions stay and harvest them from late spring til fall, when more desirable roots become available.

Inappropriate zone placement

I missed a very basic permaculture principle with many of my original polyculture designs. I didn't pay attention to what sort of yields went under which trees in the yard, and their accessibility from our front door. So I had leaf crops designed under trees in the far corner of the yard, which in practice I would almost never get around to harvesting.

Crop balance

When I first designed our guilds, I had no concept of how many leaf crops we would need vs roots, shoots, berries, seeds, etc. Since the perennial plant world offers many greens but relatively few foods from the other categories, I overdesigned leaf crops by default.

Difficulty implementing self seeding annuals

I sometimes consider myself a terrible gardener, such as when I have to admit that I failed--several years in a row--to grow pigweed (Amaranthus sp) and lambs quarters (Chenopodium album). You know, those weeds that gardeners everywhere else persistently pull out of their beds year after year. I tried several different species of amaranth, and at least two of Chenopodium, and I don't think I ever got any to grow the first year, let alone persist as an annoying weed. My original designs incorporated several other self seeding annuals: breadseed poppy (Papaver somniferum), miner's lettuce (Montia sp), land cress (Barbarea verna), corn salad (Valerianella locusta), and some biennials like evening primrose (Oenothera biennis). Only the evening primrose has really succeeded here; the rest never got started or have failed to robustly self seed. I attribute the failures to our heavily mulched, rarely dug soils. The first two years (especially the first), everything had a thick layer of wood chips. I tried spreading a thin 1" layer of soil in some places to seed plants like the amaranth & chenopodiums, but those tend to germinate in late spring or early summer with more heat, which coincides with the end of our rains and thus drying out of those 1" layers of soil. In subsequent years, we had heavy slug pressure, and rarely had bare patches of soil with full sun to support such pioneering annuals, especially late in the season. I did include root crops amongst those self-seeding annuals in my original design, to facilitate creation of bare soil, but with the exception of evening primrose (whose root I dig over the winter), those combinations of digging & self-seeding never really came together.

Spring Ephemerals Not So Useful

I made a small design mistake by including, in each guild, a spring ephemeral as suggested in Edible Forest Gardens. These ephemerals begin growing in late winter or early spring, taking advantage of full sun conditions before shrubs and trees above them leaf out. They flower early in the season, then die back to the ground as shade increases. On the east coast, with its harsher winters and frequent late winter snowpacks, these ephemerals play a crucial role in "catching" nutrients early, preventing snow melt or rains from leaching them out before the woody plants come into growth. In the pacific northwest, we have mild winters with many warm spells throughout the winter allowing some plant growth. In Portland we never get a real snow pack. Here it makes more sense to incorporate evergreens or fall planted crops such as garlic and fava beans. The ephemerals I've tried have competed poorly with other perennials and the late winter/early spring annual weeds.

If I Knew Then What I Know Now...

If I had the opportunity to do this all again, I would:
  • Design with the plants available to me, so I could plant them all out at once. (I would reserve some areas as nursery & trial beds for new experiments.)
  • Plant out low growing or easily removable ground covers everywhere I'm not yet ready to implement permanent designs. Selection criteria:
    • Evergreens preferred
    • Winter leaf crops
    • Berries
    • Duck forage
    I haven't put much thought into this, but some ideas on species:
    • Evergreen violets such as Viola odorata (edible leaves & flowers)
    • Evergreen bellflowers such as Campanula poscharskyana and C. portenschlagiana (edible leaves & flowers)
    • Bunchberry (Cornus canadensis) as a native berry crop. This did poorly in early years, but might succeed now with more shade from maturing trees.
    • Various low growing Rubus species, such as R. nepalensis, R. tricolor, R. x stellarcticus, R. arcticus, R. pentalobus.
    • Strawberries, both garden variety and species (Fragaria sp.)
    • Perennial ground cherries (Physalis sp.)
  • Plant fewer greens, and concentrate them closer to the house since I pick them once or twice a day.
  • Plant more perennial seed crops.
  • Try to design a soil disturbance regime to suit self seeding annual seeds from Amaranthus sp. and Chenopodium sp.
  • Incorporate ducks to reduce slug pressure on leguminous seed crops of favas, peas, and runner beans.
  • Include more evergreens in general rather than spring ephemerals
  • Group root crops together for complementary soil disturbance. I'll post soon with several root polyculture ideas I'm trialing this year.
  • Skip the nitrogen-fixing function from my list of guild requirements. One person can fertilize 4000-5000 square feet of forest garden with urine.