Nitrogen fixers in the orchard

I don't have to do nitrogen fixing trees or bushes do I? Perennials like lupine and such should be just fine???

you dont have to, but then you must take on the role of adding nitrogen to your orchard.

alfalfa as a ground cover seems to work really well in my area. irrigated to start with, but once established its pretty drought tolerant.
i found roots ~4 ft down when i replaced my main water line this year.

russian olive is another good one, but considered a weed here. youll have to plant from seed.
honey locust is another
siberian pee shrub also works.

hopefully others will add more.

My 'orchard' at home is tiny, and I've made the call to only grow food-bearing trees.
I've just done a major rejig and dumped wood mulch all over the clover, but when it comes back through,
the groundcover will basically be clover (along with a load of other stuff of course )

In a larger space, I'd want to plant nitrogen fixing trees/shrubs:
they usually grow fast, so as well as nitrogen, they provide shelter for young fruit/nut trees, chop and drop mulch, trellises for vines that would swamp an immature tree...
Tagasaste is commonly used here, but I think most of the USA is too cold.

Another thing to keep in mind is whether the right bacteria are already there, or maybe you need to add them my nitrogen fixing thread

The thing about fruit trees is they are shorter in order to get some shade during the heat of the summer. A Honey Locust or similar tall nitrogen fixer is the perfect shade(not too dense) for fruit trees.

I have some bushes. Looks like I'll be moving starts to the orchard then. Thanks. Big of a bummer though.

Another great thing about locust, is that they are very resilient and can withstand major pruning. The amount of shade cast can be altered, whether it is coppiced, pollarded or randomly hacked.

"Nitrogen fixers" is one of those buzzwords enshrined within the permaculture community. Reading Bob Rodales previous work, I got interested in nitrogen fixers long before I ever even heard of the term permaculture.

The truth is I think more hype than actual results, at least in my case. I myself have planted several different nitrogen fixers that for me at least have been more or less complete failures. The ironery is that nitrogen lovers, like peaches are growing very well for me. Go figure? Let me itemize the individual problems I've had which each.

Carob: Collected seed from trees at the Palm Springs International airport. Carob could not survive the winter cold at the 5000 foot elevation of my homestead and froze out the first winter.

Mesquite: Collected seed from trees near Pheonix Arizona. Same as Carob, couldn't survive the winter cold.

Black Locust: Collected seed from trees in a botanical garden near the University of California campus. The very thorny seedlings were browsed right to the ground by deer.

Autumn Olive: Commercially purchased from a nursery. Is still alive after three years, but has put on little new growth and is obviously not thriving.

Honey Locust: Combination of commercially purchased varieties and seed from local trees. They're in the ground and not yet dead, but obviously not thriving. They're not as old as the Autumn Olive yet, so maybe they'll catch up.

Seaberry: Commercially bought seedlings. These are still in pots and haven't been transplanted out into the wild yet. Will have to wait and see.

My property is mostly southern exposure recieving full sun the whole day. Soil is very deep silt loam loess soil. Topsoil is 24" deep. Subsoil layer is at least 6-8 feet deep. The pH is 7.0.

You should consider the guild surrounding your trees as well as additional eatibles: comfrey (accumulator, but chop & drop) should be companioned with each tree, goumi berry, peanuts, bee balm are some good ones. I also plant beans at the base in the spring and the fall - they use my trees as a trellis, nettle is also good, but painful so I pass in the orchard. These are just a few.

Kelly Smith wrote:
honey locust is another

Do you have a source for this? Everything that I've read says that honey locust does not fix nitrogen, that there are no nodules on the roots. There was a single study done in 1995 or 96 that suggested that honey locust does fix nitrogen but at rates 1 to 2 times lower that nodulated tree legumes. As far as I can tell, there has been no research since. Given the number of alternatives, I wouldn't plant a species that may or may not fix nitrogen.

I wouldn't focus on nitrogen fixers as much as much as I'd focus on building soil organic matter by mulching out to the drip line with ramial wood chips. You'll get weed suppression, moisture retention, and microbial activity. This microbial activity in the form of mycorrhizal fungi help with the uptake of soluble micronutrients and extend the plant's access to water.

The USDA plant database is a good source of plants appropriate to one's needs. For example, this is a search for plants that produce the largest amount of nitrogen - http://plants.usda.gov/java/AdvancedSearchServlet?n_fix_pot_cd=High&dsp_vernacular=on&dsp_dur=on&Synonyms=all&viewby=sciname. Dr. James Duke's USDA Phytochemical and Ethnobotanical Databases are also helpful - http://www.ars-grin.gov/duke/highchem.html

Mike Haych wrote:

Kelly Smith wrote:
honey locust is another

Do you have a source for this?

Honeylocust Research Newsletter No.3 wrote:As reported in the last issue of the HR Newsletter, research by Dr. Jim Bryan at the School of Forestry at Yale University found evidence of bacterial nitrogen fixation in the roots of non-nodulating Leguminosae. These results, now expanded and reported in the refereed journal, Plant and Soil, included tests with Gleditsia triacanthos L. and twelve other non-nodulating species under different growing conditions--potting soil, sand, and bare root. Subsequent to the publication of this article, additional tests by Bryan using Gleditsia triacanthos L. have further confirmed the earlier findings.

Marianne Cicala wrote:You should consider the guild surrounding your trees as well as additional eatibles: comfrey (accumulator, but chop & drop) should be companioned with each tree, goumi berry, peanuts, bee balm are some good ones. I also plant beans at the base in the spring and the fall - they use my trees as a trellis, nettle is also good, but painful so I pass in the orchard. These are just a few.

I have comfrey growing. I planted some Nasturiums as well. Otherwise I just did lettuces and root vegetables to help stabilize my berm because I planted it very late, July. So this spring I'll be doing a lot more permanent planting in it.

From the attached:

Based on the indications of nitrogenase activity reported here, whatever mechanism or mechanisms may ultimately prove responsible, it appears that nitrogen fixation extends to non-nodulating species of the Leguminosae and that non-nodular nitrogen fixation provides a basis for the evolution of the nodular legume-rhizobial symbioses

. Unfortunately, there doesn't seem to be any other research that would have changed this final statement to a more conclusive one.

Irregardless as to whether or not Honey Locust actually fixes nitrogen, I still think it's an important addition because it's pods are a source of LEGUMINOUS protein. That's important because legume proteins, which themselves are biologically insufficent, complement the proteins in grains and nuts, which while also insufficent, are insufficent for different amino acids. Combine Honey Locust pods with any kind of nut and you'll have biologically complete protein that can sustain human life.

Michael Qulek wrote:Irregardless as to whether or not Honey Locust actually fixes nitrogen, I still think it's an important addition because it's pods are a source of LEGUMINOUS protein. That's important because legume proteins, which themselves are biologically insufficent, complement the proteins in grains and nuts, which while also insufficent, are insufficent for different amino acids. Combine Honey Locust pods with any kind of nut and you'll have biologically complete protein that can sustain human life.

The thorns rather turn me off to planting most locust and olive species. While I've nothing against their growth ability or anything else I do plan on running animals and kids through my orchard as well as opening as a U-Pick. So thorns aren't something I'm interested in.

Make sure your soil have plenty of calcium and phosphorus, as it will make nitrogen fixing plants more efficient.

Danielle,
A woody shrub you might try that I've not seen discussed in the forums is Amorpha fruticosa (a type of lead plant). Don't let the name concern anyone, it is a legume, woody, growing up to four meters tall, at least from the data I've seen. I'm growing it here in Montana, just north of you. I only have very mildly alkaline soil whereas my former garden in central Wyoming was around pH 8- UGH! I don't know how sensitive it is to pH. It stood up to last winter's crazy extreme's of +50F in late Jan followed by -20ºF below (happened twice within a month). Mine are growing like gangbusters. Lovely dark purple flowers, somewhat inconspicuous seed pods. I chopped one way back this spring and the leaders regrew about 3 feet ( one meter) or more by summer's end. I believe Eric Toensmeier lists this one on his website as a medium nitrogen fixer (http://www.perennialsolutions.org/all-nitrogen-fixers-are-not-created-equal). It might be worth looking into. i plan to to use more of them in a setup like is described in the Permaculture Orchard DVD. Seems adapted to my site and doesn't get as enormous as Caragana (Siberean pea shrub) and it's growing much faster than any of the dozens of Caragana I've planted in the last two years. I know Caragana will grow all over Wyoming and see it widespread around the dryland western USA. Agree with the person above suggesting alfalfa. It is a very deep rooted plant and heavy nitrogen fixer- a great chop and drop plant. Good luck in windy WYO! Go Pokes!

Danielle Venegas wrote:a bummer

Danielle, I'm really interested to hear more about your thoughts on the negatives of nitrogen fixing shrubs/trees.
I know you're planning for a U-pick, and all the non fruit/nut trees could be confusing for the punters.
Maybe also space? Aesthetics? Economics?
And just to make things complicated:

Michael Qulek wrote: I myself have planted several different nitrogen fixers that for me at least have been more or less complete failures

.
I think a really dense groundcover of clover that's definitely got the nitrogen fixing bacteria shouldn't be underrated.
Alfalfa is great stuff, but it does grow really tall, with very tough, 'poky' stalks of mown, which could be an issue in a U-pick scenario
alfalfa-mown-lawn thread

Elaeagnus is good - Russian olive was mentioned but there are tons of them. E. umbellata (Autumn Olive) is supposed to produce lots of edible berries besides fixing N. You can keep it pruned to minimalise shading.

Danielle Venegas wrote:The thorns rather turn me off to planting most locust and olive species. While I've nothing against their growth ability or anything else I do plan on running animals and kids through my orchard as well as opening as a U-Pick. So thorns aren't something I'm interested in.

There is a thornless Honey Locust and seed is readily available and inexpensive.

Seaberry is a small & productive NF but it does have thorns. Kids & animals can handle thorns fine, especially if they want what the thorns are protecting (think raspberries).

Cj Verde wrote:

Danielle Venegas wrote:The thorns rather turn me off to planting most locust and olive species. While I've nothing against their growth ability or anything else I do plan on running animals and kids through my orchard as well as opening as a U-Pick. So thorns aren't something I'm interested in.

There is a thornless Honey Locust and seed is readily available and inexpensive.

Seaberry is a small & productive NF but it does have thorns. Kids & animals can handle thorns fine, especially if they want what the thorns are protecting (think raspberries).

My 3 year old regularly collapses in a heap crying about grass seed stuck in his socks. lol Don't under estimate my child's ability to be a drama king! I'll look into the thornless honey locust. The question now is that I already planted some of my trees. So is it too late to slap a honey locust in between?

Leila Rich wrote:

Danielle Venegas wrote:a bummer

Danielle, I'm really interested to hear more about your thoughts on the negatives of nitrogen fixing shrubs/trees.
I know you're planning for a U-pick, and all the non fruit/nut trees could be confusing for the punters.
Maybe also space? Aesthetics? Economics?
And just to make things complicated:

Michael Qulek wrote: I myself have planted several different nitrogen fixers that for me at least have been more or less complete failures

.
I think a really dense groundcover of clover that's definitely got the nitrogen fixing bacteria shouldn't be underrated.
Alfalfa is great stuff, but it does grow really tall, with very tough, 'poky' stalks of mown, which could be an issue in a U-pick scenario
alfalfa-mown-lawn thread

The only negatives I have are all due to how I want my orchard to function and how it will need to function as a U-Pick. Nitrogen fixing trees and bushes take up space and will be confusing to many people. I fully expect to describe and explain my method of planting because it is so different, but if my U-Pick is successful I hope I will have too many people around to do that. Of course I can put it in the brochure but I have been mildly hesitant to even make a brochure or flyer or anything because it is windy here and I don't want people trashing my place with my own material. Plus I'm sure my down wind neighbors would be less than thrilled. I suppose I could simply consider heavily pruning the nitrogen fixers to minimize the negatives.

I've watched my own kids running about through my tiny orchard this summer and it's given me much insight into how the denizens are going to react to it. It would simply be so much easier if I had flowering plants about to fill that roll. I think it would be less work for me and I am doing this solo right now. When I have all 35 acres planted I will obviously have to hire help, but for now it's just me, and I work full time as well as having 2 toddlers and a house to run.

Also, the thorns.

mike mclellan wrote:Danielle,
A woody shrub you might try that I've not seen discussed in the forums is Amorpha fruticosa (a type of lead plant). Don't let the name concern anyone, it is a legume, woody, growing up to four meters tall, at least from the data I've seen. I'm growing it here in Montana, just north of you. I only have very mildly alkaline soil whereas my former garden in central Wyoming was around pH 8- UGH! I don't know how sensitive it is to pH. It stood up to last winter's crazy extreme's of +50F in late Jan followed by -20ºF below (happened twice within a month). Mine are growing like gangbusters. Lovely dark purple flowers, somewhat inconspicuous seed pods. I chopped one way back this spring and the leaders regrew about 3 feet ( one meter) or more by summer's end. I believe Eric Toensmeier lists this one on his website as a medium nitrogen fixer (http://www.perennialsolutions.org/all-nitrogen-fixers-are-not-created-equal). It might be worth looking into. i plan to to use more of them in a setup like is described in the Permaculture Orchard DVD. Seems adapted to my site and doesn't get as enormous as Caragana (Siberean pea shrub) and it's growing much faster than any of the dozens of Caragana I've planted in the last two years. I know Caragana will grow all over Wyoming and see it widespread around the dryland western USA. Agree with the person above suggesting alfalfa. It is a very deep rooted plant and heavy nitrogen fixer- a great chop and drop plant. Good luck in windy WYO! Go Pokes!

I do like the looks of that plant. I have a whole line of these bushes though and they have many starts, so I could just move some of them. I was fairly certain this is a nitrogen fixing bush though now I am a big uncertain.

Danielle Venegas wrote:Don't under estimate my child's ability to be a drama king! I'll look into the thornless honey locust. The question now is that I already planted some of my trees. So is it too late to slap a honey locust in between?

They do grow up eventually. My picky eater is in culinary school and just informed me he ate ratatouille!

How much space do you have between trees? I do like NF shrubs like seaberry or Gumi because they take up less room. The only trouble I had transplanting the HL from seed is they kept getting eaten. A few made it with heavy duty protection.

I guess you could plant alfalfa & clover but they aren't nec. as hardy as a woody NF.

Cj Verde wrote:

Danielle Venegas wrote:Don't under estimate my child's ability to be a drama king! I'll look into the thornless honey locust. The question now is that I already planted some of my trees. So is it too late to slap a honey locust in between?

They do grow up eventually. My picky eater is in culinary school and just informed me he ate ratatouille!

How much space do you have between trees? I do like NF shrubs like seaberry or Gumi because they take up less room. The only trouble I had transplanting the HL from seed is they kept getting eaten. A few made it with heavy duty protection.

I guess you could plant alfalfa & clover but they aren't nec. as hardy as a woody NF.

The space between trees varies a bit. I have trees varying from Standard, Semi-Dwarf and Dwarf. I'd say the average space between trees is 10 feet.

So I was just looking at the forestry instructions on growing HL from seed and it stated they aren't nitrogen fixing. I know you've had this discussion with someone else here. I'll see what I can get to grow I suppose.

Ok yes, the shrub I have growing is nitrogen fixing. It's Caragana Arborescens and it's doing very well here as the very first line of defense in my tree line.

Danielle Venegas wrote:So I was just looking at the forestry instructions on growing HL from seed and it stated they aren't nitrogen fixing. I know you've had this discussion with someone else here. I'll see what I can get to grow I suppose.

It's a little higher up in this thread. If you've seen The Permaculture Orchard, that's the NFixer they use. If not, consider purchasing the video because it's awesome.

Ok yes, the shrub I have growing is nitrogen fixing. It's Caragana Arborescens and it's doing very well here as the very first line of defense in my tree line.

Caragana coppices well so it would be possible to keep it relatively small. Have you seen The Permaculture Orchard video? I urge you to check it out- it has a lot of useful information. Steffan, the narrator and owner of the orchard, plants in groups of three with apple-nitrogen fixer (he uses honey locust) and pear or other fruiting tree. My personal belief is that Caragana would work better for you as it is supremely adapted to the dryland, alkaline west, it coppices so well and you'd never have to concern yourself with thorns. Caragana supposedly starts easily from seed so you'd have a ready supply on site. Good luck!

mike mclellan wrote:

Ok yes, the shrub I have growing is nitrogen fixing. It's Caragana Arborescens and it's doing very well here as the very first line of defense in my tree line.

Caragana coppices well so it would be possible to keep it relatively small. Have you seen The Permaculture Orchard video? I urge you to check it out- it has a lot of useful information. Steffan, the narrator and owner of the orchard, plants in groups of three with apple-nitrogen fixer (he uses honey locust) and pear or other fruiting tree. My personal belief is that Caragana would work better for you as it is supremely adapted to the dryland, alkaline west, it coppices so well and you'd never have to concern yourself with thorns. Caragana supposedly starts easily from seed so you'd have a ready supply on site. Good luck!

I've watched his Youtube videos and would love to intern there. LOVE LOVE LOVE! Eventually!

My Caragana is sending out shoots everywhere and I have been digging them up and planting them all over the property. I'll just intermix them with the trees now.

I've been planting Amorpha fruticosa (false indigo) along my tree-growing systems (swales) as an N-fixer and to attract pollinators. http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b660 The flowers are 2 to 6 inches long with dense clusters of purple tube-shaped flowers. This shrub is in the legume family and the seeds are eaten by quail and other wildlife. Bees and butterflies are attracted to the flowers. Mature Height: 12 feet. Just another option to consider.

For cool climate (zone 6) i always plant them in a forest garden, not just for N-fixing, this plants are also great support for vines, somteimes they fruit, biomass when coppiced, pollarded, wind protections and more...
- golden chain tree (Laburnum spp.) (pollarded or high pruned tree or coppiced, support)
- autumn olive (fast growing, potential biomass, also great fruit shrub)
- alfalfa, red, white clover (fast growing cover, paths, early years inbetween young trees)
- Italian Alder (Alnus cordata) (coppice or high pruned tree or polarded, support)
- Black Alder (Alnus glutinosa) (fast growing, biomass, coppice or polarded)

Dan Grubbs wrote:I've been planting Amorpha fruticosa (false indigo) along my tree-growing systems (swales) as an N-fixer and to attract pollinators. http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b660 The flowers are 2 to 6 inches long with dense clusters of purple tube-shaped flowers. This shrub is in the legume family and the seeds are eaten by quail and other wildlife. Bees and butterflies are attracted to the flowers. Mature Height: 12 feet. Just another option to consider.

This was suggested before. It's a pretty plan. I might add a few just for interest.

Stefan Sokowiak uses Honey Locust not only as an N-fixer, but as a support structure for blackberries, grapes and arctic kiwi, which maximizes the per square foot income. He also encouraged me to keep my alfalfa understory! We are also getting clover established where we can, for nitrogen and bees. Bees love alfalfa flowers too.

I understand completely your concerns about visitor safety (there's a post somewhere I brought up this very question). The needs of the orchard for nitrogen are most acute while the trees are getting established, so don't hesitate to pack in the support trees/bushes early and chop them out when the canopy closes. My understanding is that during the bearing years, excess nitrogen is a problem for fruit production.

Are you not Lawyer Nursery? I got Honey Locust from them this year, would be worth seeing if you can visit and pick them out. The seedling thornless aren't always thornless, but the price is so low you can afford to set aside the few with thorns if you have to mail order.

So, is the consensus that there must be some sort of plant attrition to recover any nitrogen fixing that may have happened? Makes sense to me.

Did some research on the Amorpha fruticosa (false indigo) plant being mentioned. Don't want to risk ANOTHER out of control plant, so I think I will plant Licorice instead. Is a fixer AND a cash crop too.

How about bundle weed below your trees or letting ground nut grow up your trees

Autumn olive prune very nicely. In fact, before it occurred to me to prune to reduce shade and thus enhance companion plantings, I would occasionally prune one just to create an unusual view while playing my disc golf course (integrally woven with the farm). Here are, in order, a particularly lovely bush/tree, followed by a before and after image of one that I pruned this morning. Since I am in the planning stages for the farm, this year I will grow a wide variety of things under the ones I have pruned this winter, between 20–30 so far, and see what happens.