Then it was time for that right now the last post in the plunge about kvävefixerare forest garden, which is about how we can practically choose the best plants. Before that, however, I would recommend anyone who has read this series to also take a look at the many comments that have been received on the previous interventions, they are highly readable!
What is it that characterizes a good (vedartad) kvävefixerare? From what has emerged in the literature, I think that it is important to:
- The plant bloom in early spring, to take advantage as much as possible of the incident sunlight during the spring and early summer.
- The plant has a high growth rate. The more leaf mass produced, the more sugar can be supplied with the bacteria, resulting in yet more growth and even more nitrogen bound. To it must kvävefixerarna having high production capacity have plenty of water.
- growth is fully vinterhärdig To reduce the risk of frost damage, that would jeopardize next year's leaf mass production.
With these criteria in mind, we can, for example, emphasize the honey locust (Gleditsia triacanthos) from List of nitrogen-fixing trees and shrubs. It turns out very late in the spring and miss an important part of the incoming sunlight. Japanese and Korean silver bush (Elaeagnus multiflora and IS. umbellata) are undecided in zone IV and north, because they can easily freeze cold winters. Last winter was reported freezings although the cultivation zone III IS. umbellata. Further south, these are very useful, and the silver deciduous shrubs are described in the literature as some of the best kvävefixerarna, Thanks to its easily soluble nitrogen that quickly becomes available for other plants and soil organisms .
Even porcelain and American porcelain (Myrica gale and M. pensylvanica) I deleted from the list. They may have their place in very wet soil, but their growth rate in the better locations are so low that they do not do much good, and rather can be replaced by other kvävefixerare.
After this thinning list becomes rather shortened, which in a way is good, because it reduces the choices and make it less complex to choose appropriate kvävefixerare. At the same time it shows that it is well worth taking a closer look at the herbaceous kvävefixerarna and examine what contribution they can make to the overall nitrogen budget. This investigation is ongoing and I hope to show results for the forest garden nitrogen budget later this year.
|Scientific name||Swedish name||Resistance||Nitrogen Fixation Ability *||Note|
|Tree||Alnus glutinosa||European alder||Sun V||high|
|Alnus incana||Grey alder||Zon VII||medium||Sending suckers and are a pain in the warmer cultivation zones. Should only be used in Zone VI and VII.|
|Robinia pseudoacacia||Robinia||Zon III||medium|
|Shrubs||Colutea arborescens||Blåsärt||Zon III||creations data|
|Caragana arborescens||Sibirisk ärtbuske||Zon VIII||medium|
|Cytisus scoparius||Harris||Zon III||high|
|Elaeagnus changed||Silverbuske||Zon VII||medium|
|Elaeagnus multiflora||Japansk silverbuske||Zon III ?||high||First in zone I-III|
|Elaeagnus umbellata||Korean silver shrubs||Zon IV ?||medium||First in zone I-III|
|Genista tinctoria||Färgginst||Sun V||creations data|
|Hippophae rhamnoides||Havtorn||Zon YOU||medium|
|Shepherdia argentea||Bisonbuske / Buffelbuske||Sun V||medium|
*according to 
This whole series is a result of the literature study in our research project entitled "Limitations and opportunities for forest gardening in Swedish climate" funded by the Royal Forest- and the Academy of Agriculture and is expected to be completed in spring 2018. More results we will post here on the blog ahead.
 Roggy, J.C., A. Moiroud, R. flew, and A.M. domains, Estimating N transfers between N2~-fixing actinorhizal species and the non-N2~-fixing Prunus avium under partially controlled conditions. BIOLOGY AND FERTILITY OF SOILS, 39: p. 312-319, 2004.
 USDA. Plants Database, Advanced Search and Download. 2017. https://plants.usda.gov/adv_search.html, Retrieved 2017.