10 Flowers and Plants That Improve Soil Health Naturally
Today we will discuss 10 flowers and plants you can grow that improve soil health naturally.
I am all about great soil health. Healthy soil is key to a thriving garden, and some plants and flowers can improve its fertility, structure, and overall health. These plants not only enrich your soil but also beautify your space. Read on for 10 flowers and plants that improve soil health, along with their USDA hardiness zone recommendations.
Improving the soil health in my garden has been a game changer. One of the biggest bonuses is it cuts down on garden maintenance. With great soil health, I save money on fertilizers, pesticides (don’t need them), and watering.
This post contains both the benefits and the cons of each.
Plants That Improve Soil Health
1. Clover (Trifolium)
USDA Zones: 3–10
Why it improves soil: Clover is a nitrogen-fixing plant that enriches the soil by converting atmospheric nitrogen into a usable form.
Note: White clover is considered invasive in many states.
How to use it:
- Grow clover as a cover crop or ground cover.
- Mircroclover is ideal for pathways, while crimson clover works well in garden beds as a cover crop. Cut it back before it goes to seed.
Cons:
- Can become invasive, spreading aggressively into unwanted areas.
- May attract bees in high-traffic areas, which could be a concern for those allergic to bee stings.
Note: Microclover is a form of White Clover that can become invasive in some areas. I keep mine mowed short in summer so no seeds develop but it still spreads by runners. I have it as a ground cover for a path and keep it in the boundaries by edging it with a weed eater and pulling any that gets into the garden beds.
2. Comfrey (Symphytum officinale)
USDA Zones: 4–9
Why it improves soil: Comfrey’s deep taproot draws nutrients like potassium, calcium, and phosphorus from deep layers of soil, enriching the topsoil. This makes these nutrients available for other plants. Some call plants like this nutrient miners.
How to use it:
- Plant as a perennial mulch source.
- Harvest leaves for compost or as a nutrient-rich mulch layer. When the plant is picked or cut and soaked in water until it is stinky, it makes a fabulous plant food. But it is super smelly!
Cons:
- Difficult to remove once established due to its deep and persistent root system.
- Can spread rapidly, becoming invasive in some areas.
3. Lupines (Lupinus)
USDA Zones: 4–8
Why it improves soil: As a legume, lupines fix nitrogen into the soil, improving fertility for future crops. Their deep taproots also aerate and loosen compacted soil. Many lupine species are short-lived perennials or annuals.
How to use it:
- Use in ornamental borders or as a green manure crop.
- Cut the foliage of plants after flowering and let it fall onto the soil surface as mulch for added organic matter.
Cons
- Can be toxic to pets and livestock if ingested.
- May not thrive in areas with high humidity or poor drainage.
Related: Grow Lovely Lupines in Your Garden!
4. Buckwheat (Fagopyrum esculentum)
USDA Zones: 3–10 (grown as an annual)
Why it improves soil: Buckwheat grows rapidly, suppressing weeds and scavenging phosphorus, which becomes available for future plants. Buckwheat can also help to balance the PH of soils
How to use it:
- Plant as a fast-growing summer cover crop.
- Mow or till it before it sets seed to add organic matter to the soil. I let it grow amongst my flowers and cut back with pruners as I wish.
Cons:
- Needs to be mowed or tilled before it sets seed; otherwise, it can become a weed.
- Sensitive to frost, limiting its planting window.
5. Sunflowers (Helianthus annuus)
USDA Zones: 2–11 (grown as an annual)
Why it improves soil: Sunflowers have long taproots that break up compacted soil, improve drainage, and bring nutrients to the surface.
How to use it:
- Use in areas with poor or compacted soil to improve structure.
- Compost spent stalks and leaves to boost organic matter.
Cons:
- Produces allelopathic compounds that may inhibit the growth of certain nearby plants.
- Can grow very tall, shading smaller plants.
Related: Grow Sunflowers in Your Garden – It’s So Easy!
6. Marigolds (Tagetes patula)
USDA Zones: 2–11 (grown as an annual)
Why it improves soil: Marigolds suppress harmful nematodes with their natural compounds, improving soil health for subsequent crops.
Note: only French Marigolds have any effect on harmful nematodes.
How to use it:
- Plant around vegetable beds or as a nematode-suppressing cover crop.
- Add the spent flowers to compost to recycle nutrients.
Cons:
- Needs to be replanted yearly.
- Some gardeners find their distinct scent unpleasant.
- May not control nematodes effectively if not planted in sufficient quantities.
7. Daikon Radish (Raphanus sativus var. longipinnatus)
USDA Zones: 2–11 (grown as an annual)
Why it improves soil: Daikon radishes, also called tillage radishes, break up compacted soil and improve aeration with their deep roots.
How to use it:
- Plant as a fall cover crop.
- Let the roots decompose in the soil to fertilize and loosen it naturally.
Cons:
- Decaying roots can create an unpleasant odor.
- Can attract pests like root maggots and flea beetles. (counter measures include row covers and beneficial insects)
8. Yarrow (Achillea millefolium)
USDA Zones: 3–9
Why it improves soil: Yarrow’s deep roots mine nutrients like potassium and calcium, making them available for nearby plants. It also helps speed up compost decomposition.
How to use it:
- Grow in borders or pathways for ornamental and soil benefits.
- Add leaves to compost piles to boost decomposition.
Cons:
- Can spread aggressively via rhizomes, potentially becoming invasive.
- Self-seeds prolifically, requiring regular deadheading or thinning.
How to Grow Yarrow aka Achillea
9. Alfalfa (Medicago sativa)
USDA Zones: 3–10
Why it improves soil: Alfalfa is a nitrogen-fixing legume with deep roots that improve soil structure and fertility.
How to use it:
- Grow as a perennial cover crop or green manure.
- Cut back periodically and till into the soil to add nutrients.
Cons:
- Requires consistent mowing or tilling to prevent it from becoming weedy.
- Can deplete soil moisture quickly, competing with nearby plants.
Instead of growing it, I use alfalfa hay as a mulch. I take flakes from the bale that are about 2 inches thick and lay them down to cover the ground. This prevents weeds while feeding the soil. The worms love it.
Using Alfalfa In the Garden
10. Borage (Borago officinalis)
USDA Zones: 2–11 (grown as an annual)
Why it improves soil: Borage accumulates potassium and calcium from deep in the soil, making it accessible to other plants. It also attracts pollinators.
How to use it:
- Plant as a companion to vegetables or in pollinator gardens.
- Use spent plants in compost for nutrient-rich organic matter.
Cons:
- Self-seeds aggressively and can spread uncontrollably if not managed.
- Large leaves and stems can be prickly, making it less pleasant to handle.
Tips for Using These Plants to Improve Soil Health
- Plan for rotation: Incorporate legumes like clover, alfalfa, or lupines in crop rotations to maintain soil fertility.
- Embrace cover crops: Use fast-growing options like buckwheat and daikon radishes between planting seasons.
- Add organic matter: Chop and drop plants like comfrey, sunflowers, and borage for mulching and composting.
By integrating these 10 plants into your garden, you’ll nurture not just your plants but also the soil beneath them, creating a thriving, sustainable garden for years to come.
Which of these soil-improving plants have you tried? Share your experience in the comments below!
Happy Healthy Soil Gardening!
I love this list, Pamela. Some of these tips I knew but many I did not! I live in Zone 6b along the North Shore of Massachusetts. I have lots of land and love gardening but for many years now we have been under a water ban during the summer months and my border gardens suffer from the lack of water. My hostas could be so much bigger if they just had more water! Late May and early June are the best months for my yard. I love seeing the color combinations that you put together and will be watching to see what’s new this year in your lovely garden. Jan in MA