How Plant Sociability Is Critical in Natural Gardens and Shorelines

Picture this: You’ve spent hours on a carefully designed native plant garden, only to find your Butterfly Milkweed disappears under an aggressive mass of Yarrow. These isn’t just a random garden failure – it’s a violation of plant sociability, one of the most overlooked principles in ecological garden design.

Just as some people thrive at large parties while others, like me (!), prefer intimate gatherings, plants have evolved distinct social tendencies. Understanding these hidden social rules could be the difference between creating a harmonious, self-sustaining plant community and an unstable landscape that fights against its own nature.

The Four Social Personalities of Plants

In natural landscapes, plants aren’t randomly scattered – they follow distinct patterns of growth and community formation. These patterns can be classified into four “social personalities,” each with its own rules for how it interacts with neighbours:

The Introverts (Level 1)

These are the solo artists of the plant world. Think of Butterfly Milkweed or Rough Blazingstar – plants that naturally maintain their personal space and lose their impact when crowded together.

The Small Group Socializers (Level 2)

Like friends who prefer intimate dinner parties, these plants thrive in small clusters of 3-10. Spotted Joe Pye Weed and Grey Goldenrod are good examples.

The Party Minglers (Level 3)

These are your gradually expanding social circles – plants like Lanceleaf Coreopsis and Zigzag Goldenrod that spread steadily but know when to respect boundaries.

The Social Butterflies (Level 4)

The life of the party – plants like Silverweed and Woodland Sunflower that will spread enthusiastically through any available space. Wonderful in the right setting, overwhelming in the wrong one.

I want to note, however, that plants perform differently in different locations, so these are just rules of thumb.

Making the Most of Each Social Style

Introverts in Action (Level 1)

Here’s how to work with these independent spirits:

• Use them as focal points where their individual beauty can shine
• Plant them where they won’t be overwhelmed by more aggressive neighbours

Real-world example: Picture a Butterfly Milkweed rising above a drift of well-behaved grasses. Its orange blooms command attention precisely because it stands alone.

Small Group Dynamics (Level 2)

Wild Columbine and White Turtlehead exemplify these sociable but restrained plants:

• Plant in groups of 3-10 for natural-looking clusters
• Create rhythm by repeating groups throughout the design
• Perfect for: Creating visual anchors and seasonal displays

Real-world example: A cluster of five Wild Columbines creates more impact than the same plants scattered individually.

Managing the Minglers (Level 3)

These sociable spreaders, like Heart-leaved Aster and Nodding Onion, require thoughtful placement:

• Give them room to spread but contain them with strategic barriers
• Plant them where their gradual expansion will enhance rather than disrupt
• Perfect for: Creating informal drifts and filling middle ground spaces

Real-world example: A patch of Anise Hyssop might start as three plants but will gradually fill a 4×4 foot area, creating a beautiful seasonal display that pollinators love.

Choreographing the Social Butterflies (Level 4)

These enthusiastic spreaders, like Common Yarrow and Canada Anemone, can be either your best friends or worst enemies:

• Use only in large informal areas where spread is desirable
• Avoid entirely in gardens under 200 square feet
• Think twice before combining with any Level 1 or 2 plants

Real-world example: In a rain garden’s lower basin, Canada Anemone can spread freely, creating a dynamic groundcover that adapts to changing moisture levels. But place it near your prized Level 1 specimens, and you’ll be fighting a losing battle.

Why Sociability Matters in Ecological Design

When designing gardens or shorelines, we take sociability seriously. Here’s why.

1. Creating Authentic Plant Communities

Plants in nature don’t grow in evenly spaced arrangements. By respecting sociability, we create more authentic-looking landscapes that reflect natural plant communities.

2. Optimizing Plant Performance

Plants perform better when planted according to their natural sociability.

3. Balancing Ecological Function with Aesthetics

Understanding sociability helps us balance ecological goals with human preferences. We know plants will grow in a way that satisfies our clients.

Using appropriate groupings of Level 2 plants creates visual coherence, while the strategic placement of Level 1 specimen plants enhances legibility by creating landmarks.

4. Ensuring Long-Term Landscape Performance

Understanding and applying sociability is crucial for the long-term success of plant communities. When plants with mismatched levels are combined, the more aggressive species overtake and suppress less aggressive ones, leading to:

• Reduced biodiversity
• Loss of design intent
• Increased maintenance

As a rule of thumb, it’s best to match sociability levels within plant groupings:

• Compatible combinations: Levels 1 and 2 work well together, as do Levels 3 and 4.
• Problematic combinations: Mixing Levels 1-2 with Levels 3-4 typically leads to the more aggressive plants dominating (though there are ways to mix them, if we’re careful.)

This matching principle is critical in smaller gardens where space is limited and plant competition is intensified.

5. Anticipating Change Over Time

Sociability is tied to how plants interact and spread over time. Landscapes are dynamic systems that evolve. Planting according to sociability levels helps us anticipate and work with nature rather than resist it.

Plant Sociability and Landscape Evolution

Plant sociability significantly influences landscape development over time. Here’s how different sociability levels affect landscape evolution:

Level 1 Plants (Individual Specimens)

These plants maintain their individuality over time. They don’t create drifts or colonies but remain distinct in the landscape. Their primary role in landscape evolution is to provide consistent structural elements and landmarks.

Examples of Level 1 native plants:

• Asclepias tuberosa (Butterfly Milkweed): A clumping forb that mixes well with prairie grasses while maintaining its individuality without aggressive spread.
• Echinacea pallida (Pale Purple Coneflower): A clumping forb that mixes well with prairie grasses but doesn’t spread aggressively.
• Liatris aspera (Rough Blazingstar): A 60-120 cm tall forb with grass-like leaves and purple flower spikes, forming distinct clumps that blend well with prairie grasses.
• Geum triflorum (Prairie Smoke): A 20-40 cm tall forb with fern-like leaves and distinctive feathery seed heads. It forms small clumps that blend well with other low-growing prairie plants.
• Asclepias exaltata (Poke Milkweed): A forb found as scattered individuals in woodlands, making it ideal for woodland edge plantings where individual specimens can thrive.

Level 2 Plants (Small Groups)

These plants maintain stable groups over time. They might slowly expand but generally stay within their designated areas. In the landscape’s evolution, they provide consistent seasonal interest and help maintain the design’s intended rhythm and pattern.

Examples of Level 2 native plants:

• Aquilegia canadensis (Wild Columbine): A forb that self-seeds readily but not aggressively, mixing well with other woodland edge plants.
• Asclepias incarnata (Swamp Milkweed): A 90-150 cm tall forb that forms clumps and works well with other moisture-loving perennials.
• Carex bebbii (Bebb’s sedge): A clump-forming sedge that grows 30-90 cm tall for wetland or rain garden plantings.

Level 3 Plants (Aggressive but Contained)

These plants will spread more assertively over time, expanding beyond their initial planting areas. They often form the matrix layer of a design and will increasingly dominate certain areas if not managed.

Examples of Level 3 native plants:

• Agastache foeniculum (Anise Hyssop): A forb that reaches 60-120 cm tall. It forms bushy clumps and mixes well with prairie plants and other sun-loving perennials.
• Allium cernuum (Nodding Onion): A clump-forming forb, 30-60 cm tall with slender, grass-like leaves and pink nodding flowers.
• Antennaria plantaginifolia (Plantain-leaved Pussytoes): A mat-forming forb that reaches 8-15 cm tall. It has woolly, grey-green leaves that form low mats, making a great groundcover for dry, sunny areas.
• Carex vulpinoida (Fox sedge): A clump-forming sedge that reaches 30-90 cm tall. It has fox-tail-like seed heads and is suitable for wetland or rain garden plantings.

Level 4 Plants (Most Aggressive)

These plants could transform the landscape over time through aggressive spreading. If not properly managed, they can overtake others and homogenize the design.

Examples from the Plant Database:

• Achillea millefolium (Common Yarrow): A 30-90 cm tall forb with finely divided, ferny foliage that forms spreading patches. It is best used in meadow settings where it can naturalize.
• Acorus americanus (American Sweet Flag): A wetland forb growing in dense stands, reaching 60-90 cm tall with sword-like leaves that can spread aggressively in ideal conditions.
• Anemonastrum canadense (Canada Anemone): A rhizomatous forb that reaches 30-60 cm tall and spreads to form groundcover. It is best used in areas where it can be contained.
• Apocynum androsaemifolium (Spreading Dogbane): A 60-150 cm tall and form extensive colonies. It is best for naturalized areas where it has room to spread.
• Argentina anserina (Silverweed): A low-growing forb that spreads by stolons and forms mats up to 10 cm tall. It thrives in moist areas and along water edges.

The Plant Sociability Matching Principle

To ensure long-term success of ecological plantings, it’s crucial to match plants with compatible sociability levels:

Compatible Combinations

1. Level 1 + Level 2: These lower-aggression plants can coexist successfully over time.

• Example: Echinacea pallida (Level 1) with Bouteloua curtipendula (Level 2):
• Both maintain their position without one overwhelming the other.
• Creates stable, predictable plant communities with a clear visual hierarchy.
• Requires less intervention to uphold design intent.
• Ideal for smaller gardens, formal areas, and places where design accuracy is important.

1. Level 3 + Level 4: These higher-aggression plants can be combined in appropriate settings

• Example: Carex vulpinoida (Level 3) with Acorus americanus (Level 4).
• Creates dynamic, evolving plant communities.
• Requires more space and active management.
• Best for larger naturalistic areas where some intermingling and competition is desirable.
• Creates resilient plant communities that can adjust to changing conditions.

Strategic Exceptions

Plants of different sociability levels can be combined with suitable design and management strategies:

1. Physical Barriers: Using hardscape elements or natural features to separate sociability zones

• Example: Separating Level 1-2 plants from Level 3-4 plants with a path

1. Zoned Approach: Creating distinct planting zones for varying sociability levels

• Example: Level 1-2 plants in more formal, visible areas and Level 3-4 in larger background areas.

Practical Application Based on Garden Size

Small Garden Example (Under 200 sq ft)

For small gardens, focus primarily on Level 1 and 2 plants to maintain stability and reduce management:

• Structural layer (10-20%): Individual specimens of Celtis tenuifolia (Dwarf Hackberry) – Level 1
• Vignette layer (20-30%): Groups of 3-5 Echinacea pallida (Pale Purple Coneflower) – Level 1
• Matrix layer (50-70%): Small groups of Level 2 plants like Bouteloua curtipendula (Sideoats Grama)
• Design principle: Strictly match sociability levels, avoiding Level 3-4 plants entirely or using very limited quantities with strong containment.

Medium Garden Example (200-2000 sq ft)

For medium-sized gardens, use sociability matching zones:

• Zone 1 (More formal/visible areas): Level 1-2 plants like Asclepias tuberosa (Level 1) and Aquilegia canadensis (Level 2)
• Zone 2 (Transitional areas): Carefully managed Level 3 plants like Agastache foeniculum
• Zone 3 (Background/informal areas): In areas where they have space to spread, select Level 4 plants like Achillea millefolium.
• Design principle: Create clear transitions between sociability zones with pathways or other barriers.

Large Garden Example (Over 2000 sq ft)

In larger gardens, thoughtful placement can accommodate all sociability levels:

• Formal entry areas: Level 1-2 plant combinations for curated aesthetics
• Naturalized areas: Level 4 plants like Anemonastrum canadense (Canada Anemone) where they can spread naturally
• Design principle: Use shifting sociability levels to create diverse experiences throughout the landscape.

Conclusion

Sociability is a cornerstone concept in ecological garden design. By understanding plant sociability and, crucially, matching compatible levels, we can create landscapes that:

1. Look and function more like natural systems.
2. Perform better ecologically with lower resource inputs.
3. Evolve in predictable and manageable ways.
4. Balance human aesthetic preferences with ecological goals.
5. Require maintenance appropriate to their design intent.
6. Maintain their intended composition and character long-term.

Designing landscapes that pass the test of time is more difficult than it seems. But don’t worry, Grounded is here to help. To talk more, please visit our services page.