Can You Underplant Fruit Trees? - Plant Care Guide

Yes, you can absolutely underplant fruit trees, and it's a practice gaining popularity in sustainable gardening known as guild planting or companion planting. Underplanting involves growing smaller, beneficial plants around the base of a fruit tree to create a mutually supportive ecosystem. When done thoughtfully, underplanting can improve soil health, suppress weeds, deter pests, and even attract pollinators, ultimately benefiting the health and productivity of your fruit trees.

What is underplanting (guild planting) around fruit trees?

Underplanting (often called guild planting or companion planting) around fruit trees is a horticultural strategy that involves growing a carefully selected group of beneficial plants in the area beneath a fruit tree's canopy. The goal is to create a self-sustaining, mutually supportive ecosystem that mimics natural forest edges, enhancing the health and productivity of the central fruit tree.

Here's a breakdown of what underplanting (guild planting) entails around fruit trees:

1. Concept:

   • It's based on the principles of permaculture and ecological gardening, where diverse plant communities work together.
   • Instead of a bare circle of mulch, the area around the tree is filled with a living carpet of plants chosen for specific functions.

2. Layers of a Fruit Tree Guild: A well-designed guild typically includes plants that fulfill different roles, forming various "layers" around the central fruit tree:

   • The Fruit Tree (Canopy Layer): The primary focus, providing shade and fruit.
   • Shrub Layer: Berry bushes (e.g., currants, blueberries) that can tolerate some shade from the tree.
   • Herbaceous Layer: Perennial herbs and flowers.
   • Groundcover/Spreader Layer: Low-growing plants that suppress weeds and protect soil.
   • Root Layer: Plants with deep taproots that bring up nutrients, or shallow-rooted plants that don't compete.

3. Specific Roles of Underplanted Plants:

   • Nutrient Accumulators: Plants with deep taproots that "mine" minerals from deep in the soil and bring them to the surface (e.g., comfrey, dandelion). When these plants die back or are chopped and dropped, they release nutrients for the fruit tree.
   • Nitrogen Fixers: Leguminous plants that convert atmospheric nitrogen into a usable form in the soil (e.g., clover, vetch). This naturally fertilizes the fruit tree.
   • Pest Deterrents: Plants that emit scents that confuse or repel common fruit tree pests (e.g., garlic, chives, nasturtiums, calendula).
   • Pollinator Attractors: Flowering plants that draw in bees, butterflies, and other beneficial insects to ensure good fruit set for the tree (e.g., borage, alyssum).
   • Beneficial Insect Habitats: Plants that provide shelter or alternative food sources for predatory insects that feed on fruit tree pests (e.g., yarrow, dill).
   • Weed Suppression: Groundcover plants that outcompete undesirable weeds, reducing the need for weeding and preventing competition for water and nutrients.
   • Living Mulch: Plants that provide continuous organic matter to the soil, improving soil structure and moisture retention.
   • Trap Crops: Plants that pests prefer over the fruit tree, diverting pest attention (e.g., nasturtiums for aphids).

4. Benefits to the Fruit Tree:

   • Improved soil health and fertility.
   • Reduced pest and disease pressure.
   • Increased pollination and fruit yield.
   • Better moisture retention and weed control.

Thoughtful underplanting (guild planting) transforms a monoculture into a thriving, resilient ecosystem, offering a sustainable approach to growing healthy and productive fruit trees.

What are the benefits of underplanting around fruit trees?

The benefits of underplanting around fruit trees are extensive and contribute significantly to a healthier, more productive, and more resilient orchard or garden. This practice leverages ecological principles to create a mutually beneficial environment, reducing the need for external inputs.

Here are the key benefits of underplanting around fruit trees:

1. Improved Soil Health and Fertility:

   • Organic Matter Contribution: Underplanted groundcovers and herbaceous layers continuously drop leaves and other organic matter, acting as a living mulch. This breaks down into humus, enriching the soil, improving its structure, and feeding soil microorganisms.
   • Nutrient Cycling: Plants with deep taproots (dynamic accumulators like comfrey, dandelion) "mine" nutrients from deeper soil layers and bring them to the surface. When they die back or are "chopped and dropped" (cut and left to decompose), these nutrients become available to the shallower roots of the fruit tree.
   • Nitrogen Fixation: Leguminous underplantings (clover, vetch) fix atmospheric nitrogen into the soil, providing a natural, slow-release form of nitrogen fertilizer directly for the fruit tree.
   • Mycorrhizal Fungi: A diverse plant community supports a robust soil microbiome, including beneficial mycorrhizal fungi, which extend the root system's reach and improve nutrient and water uptake for the fruit tree.

2. Weed Suppression:

   • A dense layer of desirable underplants creates competition for sunlight, water, and nutrients, effectively suppressing undesirable weeds. This reduces the need for manual weeding or herbicides.

3. Pest Deterrence and Management:

   • Repellent Plants: Certain aromatic herbs (e.g., garlic, chives, mint, rosemary, nasturtiums) planted around fruit trees can emit scents that confuse or repel common fruit tree pests, making it harder for them to locate the tree.
   • Beneficial Insect Attraction: Flowering underplants (e.g., borage, dill, yarrow, sweet alyssum) provide nectar and pollen, attracting beneficial insects such as parasitic wasps, ladybugs, and lacewings. These natural predators then feed on common fruit tree pests (aphids, mites, caterpillars).
   • Trap Cropping: Some underplants (e.g., nasturtiums, dill) can act as trap crops, drawing pests away from the main fruit tree.

4. Enhanced Pollination:

   • By attracting a continuous stream of pollinators (bees, butterflies) with diverse flowering plants, underplanting significantly increases the chances of successful pollination for the fruit tree, leading to a better fruit set and higher yields.

5. Moisture Conservation:

   • The living groundcover acts as a mulch layer, shading the soil and reducing water evaporation. This helps retain soil moisture, reducing the frequency of watering needed for the fruit tree.

6. Erosion Control:

   • A continuous groundcover helps stabilize the soil, preventing erosion from rain or wind, especially on slopes.

7. Temperature Moderation:

   • Mulched soil stays cooler in summer and slightly warmer in winter, protecting the fruit tree's shallow feeder roots from extreme temperature fluctuations.

8. Aesthetics:

   • A beautifully designed guild can be far more attractive than bare soil or a simple mulch ring, creating a lush, productive, and visually appealing landscape feature.

In essence, underplanting around fruit trees fosters a thriving, interconnected ecosystem that reduces work for the gardener while enhancing the health, resilience, and productivity of the entire garden system.

What plants are good choices for underplanting fruit trees?

Selecting the right plants for underplanting fruit trees involves choosing species that provide specific benefits, tolerate the conditions under the tree, and don't compete excessively with the fruit tree itself. The best choices are often those with different root depths, growth habits, and ecological functions.

Here are some good plant choices for underplanting fruit trees, categorized by their primary benefits:

1. Nutrient Accumulators (Dynamic Accumulators):

• Comfrey (Symphytum officinale): Deep taproots bring up nutrients from subsoil. Leaves are high in potassium. Excellent "chop and drop" mulch. Tolerates some shade.
• Dandelion (Taraxacum officinale): Deep taproots break up soil, draw up nutrients. Attracts pollinators. Edible.
• Yarrow (Achillea millefolium): Accumulates potassium, phosphorus, and copper. Attracts beneficial insects.
• Fava Beans (Vicia faba): (Annual) Can be grown and chopped/dropped to add nutrients.

2. Nitrogen Fixers:

• Clover (Trifolium spp. - White, Red, Crimson): Low-growing, suppresses weeds, and fixes nitrogen. White clover is a popular choice as a living groundcover.
• Vetch (Vicia spp. - Hairy, Common): Also a nitrogen fixer and good groundcover. Can be vining, so may need management.
• *Lupine (Lupinus spp.):* Nitrogen fixer, deep taproots, and attractive flowers. (Note: Some species are toxic).

3. Pest Deterrents / Repellents:

• Garlic (Allium sativum): Repels aphids, spider mites, borers, and deer. Plant around the drip line.
• Chives (Allium schoenoprasum): Milder onion scent, repels aphids, attracts beneficials.
• *Marigolds (Tagetes spp.):* Repel nematodes (especially French marigolds) and some other pests.
• Nasturtiums (Tropaeolum majus): Can act as a "trap crop" for aphids, drawing them away from fruit trees. Also edible.
• Tansy (Tanacetum vulgare): Repels ants, flies, and Japanese beetles. (Note: Can be invasive and toxic in large quantities, use with caution).
• *Mint (Mentha spp.):* Repels aphids, ants, and mice. Plant in containers to prevent invasiveness.

4. Pollinator Attractors / Beneficial Insect Habitats:

• Borage (Borago officinalis): Attracts bees and other pollinators, edible, accumulates calcium and potassium.
• Sweet Alyssum (Lobularia maritima): Low-growing, produces masses of tiny flowers that attract small beneficial insects like parasitic wasps and hoverflies.
• Dill (Anethum graveolens): Umbelliferous flowers attract lacewings and parasitic wasps.
• Calendula (Calendula officinalis): Attracts beneficials, edible petals.
• Yarrow (Achillea millefolium): (Also a nutrient accumulator) Flat-topped flowers attract a wide range of beneficial insects.

5. Groundcovers / Weed Suppressors (Living Mulch):

• *Strawberries (Fragaria spp.):* Edible, spreads well, excellent groundcover. Tolerates some shade.
• Creeping Thyme (Thymus serpyllum): Drought-tolerant, fragrant, attracts pollinators, good weed suppressor.
• White Clover (Trifolium repens): (Also a nitrogen fixer) Low-growing, tolerant to foot traffic, good weed competitor.

Considerations when choosing:

• Light Levels: Choose plants suited to the light conditions under the mature tree canopy (which will be shadier than the surrounding area).
• Root Competition: Select plants with different root depths than the tree, or those that are not overly vigorous competitors.
• Growth Habit: Ensure they don't become invasive or smother the tree.
• Regional Suitability: Choose plants that thrive in your local climate.
• Water Needs: Select plants with similar water requirements to your fruit tree.

By thoughtfully combining these beneficial plants, you can design a thriving and productive underplanting system around your fruit trees.

How do you establish and manage an underplanting guild around fruit trees?

Establishing and managing an underplanting guild around fruit trees requires careful planning and ongoing observation to ensure the chosen plants complement rather than compete with the fruit tree. The goal is to create a harmonious, low-maintenance ecosystem.

Here's how to establish and manage an underplanting guild around fruit trees:

1. Planning and Design:

1. Assess Your Site:

   • Light: Observe the sun patterns around your fruit tree. As the tree matures, the underplanting area will become shadier. Choose plants accordingly.
   • Soil: Conduct a soil test to understand pH and nutrient levels, informing your plant choices.
   • Water: Consider your existing irrigation for the tree and whether underplants will need similar or different watering.

2. Choose Your Plants:

   • Select 5-7 (or more) plants from the beneficial categories (nitrogen fixers, accumulators, repellents, attractors, groundcovers).
   • Ensure they are suitable for your hardiness zone and the light/soil conditions.
   • Prioritize species that are perennial or self-seeding annuals for longevity.

3. Consider Tree Age:

   • Young Trees: Start with less vigorous underplantings or leave a larger clear zone around the trunk (1-2 feet) to reduce root competition for the developing fruit tree. As the tree grows and its root system is established, you can gradually expand the guild.
   • Mature Trees: Can handle more vigorous underplantings.

2. Establishment Process:

1. Prepare the Area:

   • Clear Weeds: Thoroughly remove all existing weeds from the area where you plan to underplant. This is crucial for giving your chosen plants a clean start.
   • Amend Soil (Optional): Lightly top-dress with compost or aged manure to enrich the soil for your new underplantings.
   • Define Zone: Consider defining the guild area with a shallow trench or edge to help manage spread.

2. Planting:

   • Timing: Plant your understory plants in spring or fall, following their specific planting guidelines.
   • Spacing: Space plants according to their mature size, ensuring they don't overcrowd each other or the tree trunk.
   • Layering: Place taller herbs/shrubs further out, closer to the drip line, and lower groundcovers closer to the trunk (but still maintain a small clear zone around the tree trunk for airflow and easy inspection).
   • No Root Disturbance to Tree: Be extremely careful not to damage the fruit tree's roots when digging holes for underplants. For young trees, avoid aggressive digging near the root ball.

3. Initial Watering:

   • Water newly planted underplants thoroughly to help them establish.

3. Ongoing Management:

1. Watering:

   • Monitor moisture levels for both the fruit tree and the underplants. You may find you water less frequently due to the living mulch effect. Use a soil moisture meter.

2. "Chop and Drop" (for Dynamic Accumulators):

   • For plants like comfrey, allow them to grow for a while, then cut their leaves down (chop) and leave them to decompose on the soil surface (drop). This returns accumulated nutrients to the topsoil. Repeat several times a season.

3. Pruning:

   • Manage Growth: Prune underplants to prevent them from becoming too vigorous and competing excessively with the fruit tree or smothering other guild members.
   • Prevent Flowering (Optional): For nitrogen fixers like clover, you can occasionally mow or trim them to prevent flowering and direct more energy to root development and nitrogen fixation.

4. Pest and Disease Monitoring:

   • Observe your entire guild (tree and underplants) regularly for signs of pests or diseases. The diversity of the guild should naturally reduce many issues.

5. Fertilization (Minimal):

   • With nitrogen fixers and dynamic accumulators, the need for supplemental fertilizer for the fruit tree should be reduced. Rely on annual top-dressing with compost.

6. Weed Control:

   • The dense underplanting should largely suppress weeds, but hand-pull any stubborn weeds that manage to grow through.

Establishing and managing an underplanting guild around fruit trees is a dynamic process, but with consistent care and observation, it creates a resilient, productive, and beautiful garden space.

What fruit trees are best suited for underplanting guilds?

While many fruit trees can benefit from underplanting guilds, some are inherently better suited due to their growth habit, canopy density, and specific needs. Trees that are more amenable to companion planting tend to be those that don't cast overly dense shade and have moderately deep root systems.

Here are some fruit trees best suited for underplanting guilds:

1. Apple Trees (Malus domestica):

   • Suitability: Excellent choice. Apples benefit greatly from improved soil health and pest/pollinator attraction.
   • Canopy: Their canopy can be managed with pruning to allow dappled sunlight through, which many underplants prefer.
   • Common Pests: Apple trees face numerous pests (aphids, codling moth) and diseases (scab), making pest-deterring and beneficial-attracting underplants very valuable.

2. Pear Trees (Pyrus communis):

   • Suitability: Very similar to apples in their needs and benefits from guild planting.
   • Canopy: Usually have a more upright, open canopy, allowing more light for underplanting.
   • Common Pests: Also benefit from pest deterrents and beneficial insect attractors.

3. Cherry Trees (Sweet and Tart) (Prunus avium, Prunus cerasus):

   • Suitability: Good candidates. Cherries are often susceptible to aphids, so aphid-repelling plants can be helpful.
   • Canopy: Can grow quite large, so underplants must tolerate increasing shade over time.
   • Pollination: Benefit significantly from pollinator attractors.

4. Plum Trees (Prunus domestica):

   • Suitability: Well-suited for guilds. They can be prone to certain pests and diseases, so strong guild companions are advantageous.
   • Canopy: Often grow to a manageable size, allowing good light penetration.

5. Peach and Nectarine Trees (Prunus persica):

   • Suitability: Can be underplanted, but with a slight caveat. Peaches are prone to fungal issues (e.g., peach leaf curl), so good air circulation is paramount. Underplanting needs to be well-managed to avoid excess humidity around the trunk.
   • Benefit: Still benefit from nutrient accumulators and pollinator attractors.

6. Fig Trees (Ficus carica):

   • Suitability: Excellent for guilds, especially in warmer climates where they are grown outdoors. They often have a more open, shrubby growth habit.
   • Pest Resistance: Generally less susceptible to insect pests, but still benefit from improved soil and weed suppression.

7. Citrus Trees (Citrus spp. - in appropriate climates):

   • Suitability: In warm, frost-free climates, citrus trees thrive in guilds. They are heavy feeders and benefit from nitrogen fixers and nutrient accumulators.
   • Pest Control: Can attract many pests (aphids, scale, leafminers), so pest-repelling and beneficial-attracting plants are highly valuable.

Considerations for Less Suitable Fruit Trees:

• Trees with Very Dense Canopies: Trees that cast very deep, continuous shade (e.g., some types of mature nut trees like Black Walnut, which also has allelopathic properties) might make it very difficult for most underplants to thrive.
• Trees with Shallow, Aggressive Root Systems: Trees with very shallow, competitive root systems might not be ideal for underplanting, as the underplants would struggle for resources.
• Disease Susceptibility: For trees highly susceptible to certain soil-borne diseases, careful selection of underplants is needed to avoid exacerbating issues.

In general, most commonly grown fruit trees can successfully be integrated into an underplanting guild, particularly if you match the underplants to the specific light and soil conditions created by the tree.

What are the risks and challenges of underplanting fruit trees?

While underplanting fruit trees offers many benefits, it's not without its risks and challenges. Thoughtless execution can lead to competition, increased pest/disease issues, or even harm the fruit tree. Understanding these potential pitfalls is crucial for successful guild planting.

Here are the risks and challenges of underplanting fruit trees:

1. Competition for Resources (Main Risk):

   • Water and Nutrients: The most significant challenge. All plants need water and nutrients. If underplants are too vigorous, too numerous, or have similar root depths to the fruit tree, they will compete directly for these resources.
   • Especially Young Trees: Young fruit trees with underdeveloped root systems are particularly vulnerable to being outcompeted by aggressive underplants.
   • Solution: Choose plants with different root depths (e.g., deep taproots for accumulators, shallow roots for groundcovers). Provide adequate water and nutrients for the entire guild. Give young trees a wider clear zone around their trunk initially.

2. Increased Pest and Disease Issues (if not done carefully):

   • Harboring Pests: A dense underplanting can inadvertently provide shelter or breeding grounds for certain pests (e.g., slugs, snails, voles, or even some insect pests) that might then move to the fruit tree.
   • Reduced Air Circulation: Overly dense or tall underplants can reduce air circulation around the base of the fruit tree and its lower branches, creating a humid microclimate that encourages fungal diseases (e.g., black spot, powdery mildew, peach leaf curl).
   • Solution: Select pest-repellent plants. Prune underplants to maintain good airflow. Remove dead/diseased underplant material promptly. Monitor closely.

3. Management Complexity:

   • Weeding: While good underplanting suppresses weeds, it doesn't eliminate them entirely. Weeding within a dense guild can be more challenging than weeding bare soil.
   • Pruning: Underplants need their own management (pruning, "chop and drop") to prevent them from becoming invasive or overgrowing.
   • Monitoring: It requires more vigilant observation to ensure all plants are thriving and no single species is dominating or causing problems.

4. Introduction of Undesirable Plants/Invasives:

   • Aggressive Spreaders: Some plants (like mint, some clovers) can be very aggressive spreaders and may quickly outcompete desired guild members or the fruit tree if not properly managed.
   • Solution: Research plants thoroughly. Use physical barriers (root barriers, pots) for highly invasive species.

5. Difficulty with Tree Maintenance:

   • Harvesting: A dense underplanting can sometimes make it harder to access fallen fruit (if collecting) or to maneuver around the tree for pruning or pest inspection.
   • Fertilization/Watering: Applying targeted water or fertilizer to the fruit tree might be more challenging if the understory is very dense.

6. Allelopathy (Chemical Inhibition):

   • Some plants (e.g., black walnut) release chemicals into the soil that can inhibit the growth of other plants. Ensure your underplants are not allelopathic to your fruit tree (or vice-versa).

7. Time and Patience:

   • Establishing a thriving guild takes time for plants to grow and interact. It's not an instant solution.

Despite these challenges, with careful planning, plant selection, and ongoing management, the benefits of underplanting fruit trees often far outweigh the risks, creating a more sustainable and productive garden.