Finding Edible Forest Garden Patterns in Native Ecosystems: A Photo Journey

By Jason Gerhardt

In flatland riparian areas of the Front Range of Colorado, along the creeks and streams that drain the mountains, exist bountiful edible ecosystems. Most are an old-field succession turning back into riparian woodland, and are quite dynamic at that.

Broad view of the floodplain landscape. The creek is the line of forest in the background.

Broad view of the floodplain landscape. The creek is the line of forest in the background.

Historically most of these creekside habitats were subject to the same forces that kept the Great Plains largely treeless, i.e. grassland fire and heavy browsing by Bison and Spanish introduced Horses. Later stream channelization and clearing performed by settlers of European descent further reduced tree cover. These ecosystems have largely grown up with the native and introduced species side by side, though natives definitely dominate.

Into the Forest.

Into the Forest.

Steep creek bank from channelization. Makes for a very definitive edge of forest growth. Species further back on the terrace are more indicative of mesa lands.

Steep creek bank from channelization. Makes for a very definitive edge of forest growth. Species further back on the terrace are more indicative of mesa lands.

I hadn’t explored these creekside ecologies much when I went looking for one of the five extraordinarily rare “native” Apios americana patches on the Front Range. Apios in Colorado is an excellent story in and of itself. In short, Groundnut occurs in Colorado in five patches, only in Boulder County, with over 200 miles separating it from the next known patch, which is in Kansas. There are many theories of how it got here, but the popular one I like to subscribe to is that it was brought overland by indigenous groups.

I hadn’t expected to find such a dynamic diversity of plants in the South Boulder Creek Floodplain but was immediately drawn in by the foot high carpet of nitrogen fixing plains Golden Banner (Thermopsis rombifolia). Next I discovered thick stands of nitrogen fixing Lupine (Lupinus plattensis). As I began to engage further there were abundant Asparagus patches, clumps of mother Apple trees and subsequent seed sprouts, Mulberry, American Plum, Hawthorn, Chokecherry, Golden Currant (Ribes aureum), Juneberry (Amelanchier alnifolia), and False Indigo (Amorpha fruticosa). All of this was under a canopy of predominately Narrow Leaf Cottonwood (Populus angustifolia).

Carpet of N-fixing Plains Golden Banner

Carpet of N-fixing Plains Golden Banner.

Gorgeous N-fixing Lupine

Gorgeous N-fixing Plains Lupine.

Park-like woodland of Narrow Leaf Cottonwood. There are at least five Asparagus clumps in the foreground though they are nearly impossible to photograph well. Apple trees in far background.

Park-like woodland of Narrow Leaf Cottonwood. There are at least five Asparagus clumps in the foreground though they are nearly impossible to photograph well. Apple trees in far background.

Asparagus

Asparagus.

Old Apple tree

Old Apple tree.

Golden Currant. They clump around the drip line of all the Apple trees, which is a very common guild of old orchards in the high and arid west.

Golden Currant. They clump around the drip line of all the Apple trees, which is a very common guild of old orchards in the high and arid west.

Closer to the creek Riverbank Grape (Vitis riparia) and native Hops (Humulus lupulus var. neomexicanus) tangle around the nearest tree trellis. Oyster mushroom (Pleurotus ostreatus) fruits copiously on stumps and fallen logs, particularly in the log jams that hang over the water.

Riverbank Grape (on left) and Native Hops. Maybe some Apios americana too now that I look closer at the photo. Vine central.

Riverbank Grape (on left) and Native Hops. Maybe some Apios americana too now that I look closer at the photo. Vine central.

Oyster Mushroom shelf on cottonwood log hanging over water. Indicated by debris on the mushrooms the water level fluctuates for periods of submersion and subsequent fruiting, a nice natural design that could be mimicked.

Oyster Mushroom shelf on cottonwood log hanging over water. Indicated by debris on the mushrooms the water level fluctuates for periods of submersion and subsequent fruiting, a nice natural design that could be mimicked.

I stumbled upon a low thicket of Amorpha fruticosa only to realize there was a giant specimen right above me, at least 10 feet tall. Underneath this spreading and airy nitrogen fixing shrub were a few clumps of Asparagus. Then right next to my foot I noticed a recently expired Yellow Morel (Morchella esculenta) mushroom. Considering how dry it had been I was surprised to find even a dehydrated mushroom. This was a pretty nice polyculture to stumble upon, where one could get a bunch of asparagus and a handful of morels at the same time. One can’t discount the nitrogen fixing shrub just above, and a canopy of Narrow Leaf Cottonwood, which Yellow Morel is likely mycorrhizal with.

I love the look of Amorpha fruticosa, and this tall spreading specimen was the biggest I had seen in the dryland west. I’ve been wanting to plant this N-fixer in forest gardens more often, but have been unsure about its coppiceability, since it tends to take up a lot of space once mature. This old shrub confirmed that it would make a great chop and drop mulch plant for forest gardens. It will be easy to keep its size in check this way since it constantly sends sprouts up from the roots. It also casts a perfect dappled shade for high elevation climates. Unfortunately I have been unable to find it in a nursery this spring, so I will take to propagating my own.

Amorpha fruiticosa. Hard to photograph in the deep shade of the canopy. I notice lots of deadwood on all these indicating that coppicing would actually be beneficial.

Amorpha fruiticosa. Hard to photograph in the deep shade of the canopy. I notice lots of deadwood on all these indicating that coppicing would actually be beneficial.

I gathered some Amorpha seed, wrapped it in a cottonwood leaf and moved on. Up on the terrace above the creek were thick brambles of Wild Rose interspersed with Lupine, Alfalfa, and Bird’s Foot Trefoil (Lotus tenuis).  It seemed every 15 feet or so there was a big patch of Asparagus too. This terrace part of the landscape is clearly healing over from either overgrazing or some other soil disturbance.

N-fixing American Licorice and Chokecherry

N-fixing American Licorice with Chokecherry suckers.

There are many other edible and otherwise useful plants in this ecosystem, too many to list in fact. I already know what I’ll be doing in April next year when the morel/asparagus polyculture is yielding! However, the real yield here is in pattern application for the replication of these edible ecosystems. There are a lot of such niches that this edible ecosystem could fill on the Front Range plains, either along creeks or irrigation ditches. It can only be beneficial to establish more of the delicious edibles along every waterway imaginable, and bringing in the other useful species where needed. Most plains farmers either burn their ditches clean of all woody vegetation or plow as close to them as possible. This is a nice edge for farmers to put into highly functional perennial vegetation, gaining all the benefits of erosion control, wind speed reduction, and the other endless yields of trees in grassland. Not to mention the numerous edible and medicinal delights!

That or one can turn it into an even higher functioning edible ecosystem and replace the native species with better tasting and yielding domesticates like European Plum replacing American Plum, or cultivated Grapes taking the place of Riverbank Grape. American Plum makes an excellent rootstock for grafting all types of Prunus; improved grape varieties grafted onto Riverbank Grape too. Options are endless. Design from Patterns to Details!

Not all of these useful species are in close enough proximity with each other to make the best use of their functions, but certainly could be placed in closer relationship in a cultivated/tended setting. These ecosystems give me hope for the future of food!

Prunus americana in a nice single stem form. I'm 6'3" for contrast, demonstrating native plum rootstock making a perfect height for fruit picking with the added benefit of superior drought adaptiveness.

Prunus americana in a nice single stem form. I’m 6’3″ for contrast, demonstrating native plum rootstock making a perfect height for fruit picking with the added benefit of superior drought adaptiveness.