The Ultimate Guide To Nitrogen Fixing Plants

Understanding Nitrogen and Its Significance for Plants

Nitrogen is a critical element for plant growth and survival. It is a part of the chlorophyll molecule, responsible for photosynthesis, and is a primary component of plant protoplasm that constructs plant cells. Nitrogen contributes to leafy growth, aids in producing healthy flower buds, promotes fruit setting, and acts as a catalyst for other minerals.

However, plants cannot directly take nitrogen from the atmosphere, even though it is abundantly present. Instead, they absorb nitrogen in the form of nitrates from the soil. But, continuous cultivation and natural factors like sun and rain can deplete soil nitrogen levels. This is where nitrogen fixing plants come into play.

The Role of Nitrogen Fixing Plants

Nitrogen fixing plants have a unique ability to work with certain bacteria in their roots to convert atmospheric nitrogen into a form accessible to plants. This natural process, known as nitrogen fixation, is the plant kingdom's ingenious solution to the nitrogen crisis in soils.

The most notable nitrogen fixers come from the legume family. These plants have symbiotic rhizobia bacteria within nodules in their root systems that help convert atmospheric nitrogen into nitrates. However, it is worth noting that there are also non-leguminous nitrogen fixing plants, which operate similarly through a symbiotic relationship with a different type of bacteria called Frankia.

The Importance of Nitrogen Fixing Plants in Your Garden

By incorporating nitrogen fixing plants in your garden, you can sustain a natural balance and prevent soil from becoming nitrogen-depleted. Over time, nitrogen deficiency can lead to reduced productivity and failing plant health.

Many gardeners resort to synthetic or commercial nitrate fertilizers to combat this issue, but these can have negative environmental impacts. Excessive nitrogen, whether from synthetic fertilizers or overuse of nitrogen fixing plants, can destabilize the soil ecosystem, causing nutrient leaching and potential damage to local waterways and marine environments.

However, when used judiciously, nitrogen fixing plants can enhance soil structure and fertility without causing harm. It's all about striking the right balance!

A Comprehensive List of Nitrogen Fixing Plants for Your Garden

To help you get started, here's a comprehensive list of nitrogen fixing plants that you can incorporate into your garden. The list is divided into three categories: trees, shrubs, and herbaceous plants. Here's a closer look at each category.

Nitrogen Fixing Trees

1. Black Alder (Alnus glutinosa): A great starter tree for quickly improving soil.
2. Laburnum (Laburnum Alpinum or Laburnum x Watereri): A beautiful tree that also enriches the soil.
3. Siberian Pea Tree (Caragana arborescens): This tree provides nitrogen and is a great source of food for animals.
4. Black Locust (Robinia psuedoacacia): An excellent nitrogen fixer that thrives in dry climates.
5. Mimosa (Albizia julibrissin): A shade provider and nitrogen fixer with a beautiful aroma.
6. Redbud (Cercis canadensis): A small understory tree with beautiful flowers.
7. Kentucky Coffee Tree (Gymnocladus dioicus): As well as fixing nitrogen, this tree produces pods that can be used as a coffee substitute.
8. Acacia: These trees are not only beautiful but also fix nitrogen effectively.
9. Mesquite: A drought-resistant tree that provides generous shade and fixes nitrogen.
10. False Acacia (Robinia Psuedoacacia): This tree thrives in warm climates and fixes nitrogen in the soil.

Nitrogen Fixing Shrubs

1. Sea Buckthorn (Hippophae rhamnoides): A nitrogen-fixing shrub that also produces edible berries.
2. Ceanothus (California Lilac/ Tobacco Brush): This shrub fixes nitrogen and serves as a beautiful ornamental plant.
3. Autumn Olive (Elaeagnus umbellata): A robust shrub that fixes nitrogen and produces edible berries.
4. Russian Olive (Elaeagnus angustifolia): A hardy shrub that can withstand cold temperatures and still fix nitrogen.
5. Goumi (Elaeagnus multiflora): This nitrogen-fixing shrub also produces delicious berries.
6. Gorse (Ulex europaeus): A shrub that fixes nitrogen and provides excellent ground cover.
7. Broom (Cytisus scoparius): An ornamental shrub that fixes nitrogen.
8. American Bayberry/ Wax Myrtle (Myrica cerifera): This shrub fixes nitrogen and has other uses, like candle making.
9. Buffaloberries (Shepherdia): A shrub that fixes nitrogen and produces edible berries.
10. Mountain Mahogany (Cerocarpus): This beautiful shrub fixes nitrogen and is an excellent choice for dry climates.

Nitrogen Fixing Herbaceous Plants

1. Fava Beans (Vicia faba): These are not only delicious but also excellent providers of nitrogen to your soil.
2. Green Beans/ French Beans (Phaseolus vulgaris): These plants fix nitrogen and provide a tasty addition to your meals.
3. Garden Peas (Pisum sativum): A nitrogen fixer that is easy to grow and harvest.
4. Field Peas (Pisum sativum arvense): These peas fix nitrogen and can withstand colder temperatures.
5. Pigeon Peas (Cajanus cajan): These peas are drought-tolerant nitrogen fixers that also provide a high-protein food source.
6. Soybeans (Glycine max): Soybeans are excellent nitrogen fixers and are used in a variety of foods and products.
7. Peanuts/ Groundnuts (Arachis hypogaea): These plants fix nitrogen and their nuts are a great source of protein.
8. Lupins (Lupinus spp.): These plants fix nitrogen and have beautiful flowers.
9. Everlasting Sweet Pea (Lathyrus Latifolius): A perennial that fixes nitrogen and produces lovely flowers.
10. Licorice (Glycyrrhiza glabra): This plant fixes nitrogen and its root is used in candy and medicinal products.

How to Incorporate Nitrogen Fixing Plants in Your Garden

Nitrogen fixing plants can be incorporated into your garden in numerous ways. For instance, you can plant nitrogen fixing trees along the edges of your garden to provide shade for your next layer of growth. Shrubs can be planted where there's limited space and ground cover plants can be used to protect the soil surface.

Incorporating these plants in your garden requires consideration of the specific needs of each plant. Some plants may require more water, while others may need certain soil conditions to thrive. It's important to research and understand the needs of each plant to ensure they grow successfully and do their job of nitrogen fixation effectively.