nitrogen fixer

Thermopsis macrophylla - False Lupine

A west coast native annual nitrogen fixing plant in the Fabaceae family. Reminds me of Crotolaria in its growth habit and overall appearance. It looks like it has potential as a cultivated, drought tolerant biomass or cover corp species.

Thermopsis macrophylla leaf and flower.

Thermopsis macrophylla leaf and flower.

Thermopsis macrophylla flower spike.

Thermopsis macrophylla flower spike.

Lathrus ochrus - Psara, Cyprus Vetch

Lathrus ochrus is one of my favorite regional edible nitrogen-fixing covercrop species in Greece. I've not yet encountered it cultivated in North America. 

Lathyrus ochrus leaf and flower

Lathyrus ochrus leaf and flower

Also known as Cyprus Vetch, or Psara locally, the plant establishes throughout mild winters, as winter temps warm up before spring the tender edible tips start fattening up and plants put on massive amounts of vegetative growth.

Locally the leaves are eaten raw in salads with a bit of lemon, olive oil and a pinch of salt. 

It is also reported on PFAF that the seeds are edible cooked noting that caution is advised. Where I have lived in Greece there is no report of the seed being edible, although the leaves are widely consumed during early spring. 


Anagyris foetida - an underutilized Mediterranean nitrogen-fixing shrub

Anagyris flowers and leaf. 

Anagyris flowers and leaf. 

Anagyris foetida is an ultra drought tolerant memeber of the Fabaceae family. The large shrub originates in the Mediterranean Basin. The plant illustrates one of the best drought resisting strategies of mediterranean flora: the plant keeps its leaves through autumn, winter and spring, then it goes completely deciduous in summer, becoming dormant and highly resistant to drought. 

A. foetida can adapt to a wide variety of soils and has been used as a fast growing nitrogen fixing pioneer species in large-scale native restoration of fire damaged areas in Southern Europe.

I first took notice of this tree / shrub where I was living in Greece. Covered in relatively large yellow flowers in winter it stands out. The flowers then develop into relatively large pods full of hard bean / seeds. The leves remind me of Cajanus cajans, a tropical perennial edible bean producing shrub. 

Anagyris foetida leaves and maturing seedpod.

Anagyris foetida leaves and maturing seedpod.

in 2017 and 2018 I experimented with direct seeding of this species on a piece of land I am in the process of regenerating, planting Anagyris foetida at high densities as a guild / interplant among fruit and nut trees. 

I believe this large shrub has significant potential as a nitrogen fixer in Mediterranean agrorofrestry, afforestation and reforestation systems.


Elaeagnus x ebbingei - Silverberry, Oleaster


Elaeagnus x ebbingei, commonly called oleaster or Ebbing's silverberry, is from temperate / subropical Areas of Asia. It is a cross between Elaeagnus macrophylla x Elaeagnus pungens. It is a large, bushy, rounded shrub that typically grows to 8-10' tall and as wide. Branchlets lack spines. Leaves are evergreen in warm winter climates, but semi-evergreen to deciduous near the northern edge of its growing range.


Elaeagnus fruit

The seeds can be eaten raw or cooked and are a good source of protein and fats. The fruit is edible, somewhat astringent until fully ripe (almost falling off), then very good and produced in large quantities. Fruits ripen in the middle of winter when few other fruit are available. Fruit will grow to be 3 cm long by 1 cm wide when ripe.

The fruit of all Elaeagnus species are a rich source of vitamins and minerals, especially vitamins A, C and E, flavinoids and other bio-active compounds. The fruit is also a good source of fatty acids, which is unusual for fruit. 

Reportedly, current research indicates that consumption of the fruit greatly reduces the incidence of cancer in humans. Not only that but the compounds in the fruit are possibly capable of slowing or even reversing the growth of cancers that are already in the body.

Flowers are inconspicuous but emit a very agreeable aroma.


The plant is nitrogen fixing, meaning its roots have a symbiotic relationship with certain soil bacteria which form nodules on the roots of the plant and fix atmospheric nitrogen. Some of this nitrogen is used by the plant itself for its own growth, however some of the nitrogen is also available for plants growing nearby. Thus, planting E. ebbingei near other food crops can improve growth and increase productivity.

Due to the versatility of this plant, it has a wide range of uses for use in regenerative agriculture, permaculture, and agroforestry systems. It can grow in full sun or shade and can handle hot dry summers. 

Elaeagnus can have a vine-like growth habit, especially when growing in the understory of a larger tree. Prune back annually to keep the plant contained as a dense hedge or shrub, the plant can take heavy pruning and produces abundant biomass.

Elaeagnus is very wind tolerant and can be utilized as a superior windbreak. It is also highly salt tolerant. It can be heavily pruned as a hedge or let to grow freely, reaching 5 m in height.

I have planted this species in temperate Europe and the Mediterranean Basin, as well as in California, its a tough shrub with with many diverse uses. I believe Elaeagnus ebbingei has major potential for use in sustainable agriculture systems and deserves further investigation, selection and development of superior fruit / seed varieties. 


Brownea macrophylla - Rosa del monte


Native to South America - Peru, Ecuador, Colombia, Venezuela; C. America - Panama.

Typically found growing as an understory tree in the rainforest, often subject to periodic inundation.


In the Darien region of Panama the bark of Brownea is boiled in water to make tea used to treat diarrhea. The flower is considered to be "from the devil" and infused in water used for ritual baths.


Brownea can be grow easily from the large brown seeds. Some literature states that Brownea seed has a semi-hard seed coat and benefits from light scarification before sowing in order to speed up and improve germination, however I have never found this to be the case. Germinate fresh seeds in a compost rich, well drained soil mix and results should be good. Seeds to not have a very long viability. 

Brownea macrophylla is native to the moist tropics, it cannot tolerate frosts. Trees prefer a position in partial shade requiring moist soil and dense deep, rich, slightly acid soil. Trees are slow growing and, if happy, will flower when three to four year olds from seed. 

Lupinus pilosus - Altrei coffee, Tyrolian coffee

Lupinus pilosus flower 1.jpg


Lupinus pilosus, commonly called blue lupine, (also known as ‘Altreier Kaffee’, or Altrei Coffee, Hebrew: תורמוס ההרים‎, Arabic: ترمس برّي‎) from the fabaceae family. The species is thought to be endemic to Israel where it is found in Mediterranean scrubland.


Lupinus pilosus leaf.jpg

L. pilosus used to be widely cultivated as a caffeine-free coffee substitute around the village of Altrei, in the Tyrolian Alps, Northern Italy. The seeds were roasted and mixed with malt grains and infused in boiling water. I do not know how it made its way there from where it is native in the Middle East, near and around Palestine. Interestingly, not only from a cultural and historical but also from a botanical standpoint, since 2006 a local initiative is re-establishing L. pilosus cultivation in the Altrei region to revive this culinary specialty.


Lupinus pilosus seed.jpg

The plant can be propagated easily from seed. Direct seeding works best and the plant will naturalize if grown in a favorable environInitially. The small seedlings don't seem to like transplanting. The newly germinated plant quickly develops a strong root system. Seeds are best seeded in fall or late winter. They will germinate and remain small until the weather starts to warm up at which point the plant will grow rapidly. I collected seed growing from plants outside a UC Berkeley plant science facility, the large seedpods drew my attention. Now I’ve been growing the species for years, accumulating more and more seed each year. One remarkable characteristic of the flower is that is smells exactly like grape soda. Here is a PDF of an article on the use of this species as a coffee substitute. ‘Altreier Kaffee’- Lupinus pilosus L. cultivated as coffee substitute in Northern Italy