Can I grow trellis systems alongside overwinter perennials? - Plant Care Guide

Yes, you absolutely can grow trellis systems alongside overwinter perennials, and in many cases, it's a highly beneficial design strategy. The key to success lies in careful planning, selecting appropriate trellis types and placement, and ensuring compatibility between the climbing plants and the existing perennial bed to avoid competition and provide mutual benefits.

What is a trellis system in gardening?

A trellis system in gardening is a supportive structure designed to help climbing plants grow vertically. It provides something for vines, tendrils, or sprawling stems to cling to, wrap around, or be tied to, guiding their upward growth. Trellis systems are invaluable tools for maximizing space, improving plant health, and adding vertical interest to a garden.

Trellises come in a wide variety of materials, shapes, and sizes, catering to different plant types and aesthetic preferences:

• Materials: Common materials include wood (cedar, treated lumber), metal (steel, wrought iron, aluminum, often powder-coated for durability), bamboo, plastic, and even natural branches or string.
• Shapes and Forms:
  • Flat Panels/Grids: The most common form, often rectangular or square, with a grid pattern for plants to climb. Can be freestanding, attached to walls, or integrated into fences.
  • Obelisks/Towers: Conical or pyramidal structures that provide support for plants growing in a circular footprint, often used for individual climbing plants in garden beds or large pots.
  • A-Frame: Two flat panels hinged at the top, forming an "A" shape, often used for vining vegetables.
  • Arches and Pergolas: Larger, more structural forms that create walk-through passages or shaded areas, covered by climbing plants.
  • Stakes and Cages: While not traditional trellises, single stakes or grow-through cages serve a similar support function for individual plants.

How Trellis Systems Benefit Plants:

1. Space Maximization: They allow you to grow vining plants upwards, making efficient use of vertical space, which is especially beneficial in small gardens.
2. Improved Air Circulation: Lifting plants off the ground increases airflow around foliage, reducing humidity buildup and minimizing the risk of fungal diseases.
3. Better Light Exposure: Vertical growth ensures more leaves receive adequate sunlight, improving photosynthesis and overall plant vigor.
4. Easier Harvesting: Fruits and flowers are often more accessible and cleaner when lifted off the ground.
5. Enhanced Aesthetics: Trellis systems add architectural interest and a sense of height to a garden, even when plants aren't in full bloom. They can be beautiful structures in themselves.
6. Pest and Disease Control: Keeping foliage off the soil can reduce pest infestations (like slugs and snails) and soil-borne diseases.

Whether used for edibles like climbing beans or cucumbers, or ornamentals like clematis or climbing roses, a well-chosen and properly installed trellis system is an invaluable asset for many garden designs.

What are "overwinter perennials" and how do they behave seasonally?

"Overwinter perennials" refers to plants that live for more than two years and survive through the winter months, typically by going dormant. Unlike annuals that complete their life cycle in one growing season and die with the first hard frost, perennials develop a root system and crown that persist through the cold, allowing them to regrow year after year.

Their seasonal behavior is key to understanding their compatibility with trellis systems:

1. Spring (Emergence and Growth):

   • As temperatures warm, overwinter perennials emerge from dormancy. This can be new shoots from the ground (e.g., Peonies, Hostas, Daylilies) or new growth on existing woody stems (e.g., Hydrangeas, Roses, some woody Herbs).
   • They begin their vigorous growth phase, putting on foliage and preparing for flowering. This is the period when they would start to interact with or grow onto a trellis system.

2. Summer (Flowering and Peak Growth):

   • Perennials reach their peak growth and flowering in summer, producing their main show of blooms. This is when climbing perennials would fully cover a trellis system.
   • Energy is put into photosynthesis, flowering, and potentially setting seed.

3. Fall (Decline and Preparation for Dormancy):

   • As days shorten and temperatures cool, many herbaceous (non-woody) perennials begin to decline. Their foliage may yellow, brown, and eventually die back to the ground (e.g., coneflowers, hostas, astilbes).
   • Woody perennials might lose their leaves but retain their woody stems (e.g., roses, some clematis, hydrangeas).
   • During this phase, the plant is directing energy down into its root system and crown for storage, preparing for the winter. This is a crucial period of energy reserves being built.

4. Winter (Dormancy):

   • Overwinter perennials enter a dormant state to protect themselves from freezing temperatures.
   • Herbaceous perennials: Their top growth completely dies back, and they appear to vanish, leaving bare soil (or a stubble if cut back). Their survival depends on their underground roots and crowns.
   • Woody perennials: They may lose leaves but their stems remain, often appearing bare and skeletal.
   • The dormant period allows them to rest and conserve energy for the next spring's vigorous regrowth.

Understanding this seasonal cycle is vital when incorporating trellis systems alongside overwinter perennials. You need to consider how the trellis affects the perennial during its dormancy (e.g., shading, water retention) and how the perennial's mature size and root system might interact with the trellis's foundation. It also highlights that the trellis will be visible during the perennial's dormant phase.

What are the benefits of integrating trellis systems with overwinter perennials?

Integrating trellis systems alongside overwinter perennials offers several significant benefits that enhance both the aesthetics and functionality of a garden, making efficient use of space and creating dynamic visual interest.

1. Maximizing Vertical Space: This is perhaps the most obvious benefit. In gardens where ground space is limited, a trellis system allows you to "grow up." By planting climbing annuals or complementary climbing perennials on a trellis, you can double your planting area without expanding your garden footprint. This is especially useful in small urban gardens or compact flower beds where overwinter perennials are already established.

2. Extended Seasonal Interest:

   • Many overwinter perennials provide their main show in spring or early summer. A trellis system provides an opportunity to integrate climbing plants that bloom later in the season (e.g., climbing roses or clematis in summer/fall, annual morning glories) or offer lush foliage, ensuring the garden remains vibrant and interesting even after the perennials have finished their main bloom cycle or gone dormant.
   • Even when deciduous perennials die back in winter, a well-designed trellis can provide structural interest, especially if it's an attractive material like metal or artfully crafted wood.

3. Visual Layering and Depth:

   • A garden with only ground-level plants can look flat. Introducing vertical elements with a trellis system adds height, depth, and a sense of grandeur.
   • You can create beautiful visual layers, with the overwinter perennials forming a lush base, and the climbing plants drawing the eye upward, creating a more dynamic and engaging landscape.

4. Protecting Delicate Perennials:

   • A sturdy trellis system can act as a windbreak for more delicate perennials planted nearby, sheltering them from strong gusts.
   • It can also provide dappled shade for shade-loving perennials during the hottest parts of the day if a vigorous climber covers it. This needs careful planning to ensure the shade is beneficial, not detrimental.

5. Enhanced Air Circulation (for climbers): While not directly benefiting the perennial, the trellis lifts the climbing plant off the ground, improving air circulation around its foliage. This reduces the risk of fungal diseases that can otherwise spread to ground-level plants.

6. Support for Floppy Perennials: In some cases, a very sturdy trellis system or even a smaller plant support within the system can indirectly provide support for taller, somewhat floppy herbaceous perennials, keeping them upright and preventing them from sprawling over pathways.

By thoughtfully designing the integration, a trellis system alongside overwinter perennials creates a harmonious and multi-functional garden space that offers continuous beauty and maximizes planting potential.

What types of trellis systems work best with overwinter perennials?

Choosing the right trellis system is key to successful integration with overwinter perennials. The best types are those that provide stable support, offer aesthetic appeal throughout the year, and allow for appropriate management of both the climbing plants and the perennials.

1. Freestanding Obelisks/Towers:

   • Description: Conical or pyramidal structures, typically made of metal or sturdy wood.
   • Pros: Highly versatile, can be placed directly within a perennial bed, allowing a climbing plant to grow upwards without needing a wall or fence. Provides strong, all-around support. Adds strong vertical interest even in winter when herbaceous perennials are dormant. Relatively easy to move or remove if needed (though heavier ones are more permanent).
   • Cons: Can cast significant shade if a very vigorous climber covers it.
   • Best For: Individual climbing roses, clematis, sweet peas, morning glories, or even vining vegetables (like determinate tomatoes or small cucumbers) among herbaceous perennials. Look for garden obelisk trellises.

2. Flat Panel Trellises (Freestanding or Wall-Mounted):

   • Description: Traditional grid or lattice panels made of wood, metal, or plastic.
   • Pros: Offers a larger surface area for climbing. Can be freestanding (e.g., embedded into the ground or secured to posts) or mounted against a wall or fence adjacent to the perennial bed. Provides a strong backdrop for perennials.
   • Cons: Wall-mounted ones are permanent. Freestanding ones need stable anchoring to prevent tipping.
   • Best For: Creating a vertical wall of greenery or flowers behind a perennial border, for climbing roses, larger clematis, or espaliered fruit trees.

3. Arches and Pergolas:

   • Description: Larger, more structural elements that create overhead pathways or shaded areas.
   • Pros: Grand and impactful. Create outdoor "rooms" and impressive entrances within a garden with established perennials.
   • Cons: Significant investment, require substantial space, and permanent installation. Can cast dense shade.
   • Best For: Formal gardens or large spaces where you want to grow robust climbing roses, wisteria, or trumpet vines over existing perennial plantings.

4. Stakes or Cages (as part of the system):

   • While not trellises themselves, incorporating sturdy individual stakes or grow-through cages (like peony cages) for the perennials themselves can be part of a vertical design, complementing a nearby trellis. For example, a tall perennial might be staked, with a lighter climber on a trellis behind it.

Important Considerations When Selecting a Trellis:

• Plant Type: Match the trellis style to the climbing mechanism of your plant (e.g., thin wires for tendrils, thicker structures for twining stems, horizontal supports for rambling roses).
• Material Durability: Choose materials that can withstand outdoor conditions and are appropriate for your climate zone, especially since they will be visible year-round.
• Aesthetics: Select a trellis design that complements your garden's overall style, whether rustic, modern, or classic.
• Maintenance Access: Ensure the trellis design allows for easy access to both the climbing plant (for pruning, tying) and the overwinter perennials (for care, division).
• Root Disturbance: Plan where you will insert or install the trellis to minimize disturbance to the established perennial root systems.

By carefully considering these factors, you can select the most effective and harmonious trellis system to complement your overwinter perennials.

How do you safely install a trellis system near overwinter perennials?

Safely installing a trellis system near overwinter perennials requires careful planning to minimize disturbance to established root systems, ensure stability, and prevent future conflicts between the plants. The perennial's dormant period is often the safest time for installation.

1. Map Out Underground:

   • Know Your Perennials: Before digging, have a good understanding of where the perennial's roots and crown are located. Herbaceous perennials will have died back, but their root systems are still very much alive underground. Woody perennials retain their root system and base structure.
   • Utilities: Even if you think you know, always call 811 (Dig Safe) in the USA before any significant digging to locate underground utility lines (gas, water, electric, communication). This is a legal requirement and critical for safety.

2. Choose the Right Time for Installation:

   • Dormancy is Best: The ideal time to install a trellis system that requires digging posts or stakes is during the perennial's dormant period, typically late fall or early spring before new growth emerges.
   • Why: Roots are less active, reducing transplant shock or damage to the perennial. You can also more clearly see where the perennial crown is.
   • If installing a wall-mounted trellis, this can be done anytime, but avoid vigorous growth seasons if it requires working close to the plants.

3. Minimize Root Disturbance:

   • Strategic Placement: Position the trellis's support posts or legs away from the immediate crown of the perennial. Aim for the outer edges of the perennial's mature size or beyond.
   • Narrow Footprint: Choose trellis designs with narrow, deep stakes or posts rather than wide, shallow bases that would disturb more surface roots.
   • Dig Carefully: If digging post holes, dig slowly and carefully. If you encounter large perennial roots, try to dig around them rather than cutting them directly. If cutting is unavoidable, use sharp, clean pruners to make a clean cut.

4. Ensure Trellis Stability:

   • Deep Anchoring: Whatever trellis type you choose, ensure its vertical supports are anchored deeply and securely into the ground. A wobbly trellis can damage both the climbing plant and nearby perennials.
   • Materials: Metal trellises are often easier to insert deeply. Wooden posts may require concrete footings for long-term stability, especially if they are tall and exposed to wind.
   • Wind Load: Consider the prevailing winds in your garden. A tall trellis with a vigorous climber will catch a lot of wind, so it needs to be very secure.

5. Consider Future Growth of Both Plants:

   • Perennial Spread: Think about the mature width and height of your overwinter perennial. Ensure the trellis won't become engulfed or restrict the perennial's growth in a few years. Allow adequate space.
   • Climber Vigor: Choose a climbing plant whose mature size and vigor are appropriate for the trellis and won't overwhelm or shade out the perennial too much (unless that's your intent, as with providing afternoon shade).

6. Site Preparation:

   • Clear the area around the installation spot of any weeds or old debris.

By meticulously planning and carefully executing the installation, you can successfully and safely introduce a trellis system alongside overwinter perennials, ensuring a harmonious and thriving garden display.

How do you select compatible climbing plants for a trellis system near overwinter perennials?

Selecting compatible climbing plants for a trellis system near overwinter perennials is essential for a harmonious garden design that prevents competition, ensures both plants thrive, and provides continuous visual interest. The choice depends on the perennial's characteristics and your desired effect.

Key Compatibility Factors:

1. Sunlight Requirements:

   • Match Needs: Ensure both the climbing plant and the overwinter perennial have similar sunlight requirements.
     • If the perennial needs full sun, choose a sun-loving climber (e.g., climbing roses, most clematis, morning glories).
     • If the perennial prefers partial shade, choose a climber that can tolerate or prefers some shade (e.g., some clematis varieties, certain ivies, hardy kiwi).
   • Shading Impact: Consider how much shade the mature climbing plant will cast on the perennial, especially if the trellis is large and densely covered. For sun-loving perennials, too much shade from the climber can reduce their vigor and flowering.

2. Watering Needs:

   • Similar Preferences: Ideally, select climbers that have similar watering needs to your perennials. This simplifies irrigation.
   • Avoid Extremes: Don't pair a very drought-tolerant perennial with a water-guzzling climber, as one will likely suffer.

3. Growth Habit and Vigor:

   • Non-Aggressive Climbers: Avoid extremely vigorous, rampant climbers (e.g., some types of Wisteria unless you're prepared for aggressive pruning) that could quickly overwhelm, strangle, or severely outcompete your perennials.
   • Match Scale: Choose a climber whose mature size is proportionate to the trellis and the surrounding perennials. A delicate perennial might be overshadowed by a huge climber.
   • Climbing Mechanism: Match the climber's tendrils/twining stems/rambling habit to the trellis structure (e.g., thin wires for tendrils, thicker structures for twining).

4. Root Competition:

   • Surface Roots: Be mindful of perennials with extensive surface root systems. Avoid planting aggressive climbers too close that would compete heavily for surface nutrients and water.
   • Deep Roots: Ideally, choose climbers with relatively deep root systems or manage surface roots carefully with proper watering and mulching.

5. Aesthetic Complement:

   • Bloom Time: Select climbers that bloom at a different time than your perennials to extend the flowering season and provide continuous interest. For example, spring-blooming perennials can be complemented by summer-blooming clematis or roses.
   • Color and Texture: Choose colors and leaf textures that harmonize with your perennials.
   • Form: Consider the overall shape and flow. A loose, airy climber might complement a structured perennial, or vice versa.

Good Combinations to Consider:

• Roses + Clematis: A classic pairing. Many clematis varieties can be grown to weave through shrub roses or climbing roses on a trellis, providing successive blooms.
• Clematis + Herbaceous Perennials: A smaller clematis can climb an obelisk amidst hostas or daylilies, adding vertical bloom.
• Morning Glory + Late-Summer Perennials: An annual vine can provide a quick, lush burst of color on a trellis while fall-blooming perennials like asters or sedums are coming into their own.
• Sweet Peas + Spring Perennials: Sweet peas can add early season vertical color while spring bulbs and perennials are in bloom.

By carefully considering these compatibility factors, you can select climbing plants that not only thrive on their trellis system but also enhance and coexist beautifully with your overwinter perennials.

What kind of maintenance is required for trellis systems and perennials throughout the seasons?

Maintaining trellis systems and overwinter perennials requires ongoing attention throughout the seasons to ensure both remain healthy, productive, and aesthetically pleasing. The symbiotic relationship means that care for one often impacts the other.

Spring Maintenance:

1. Inspect Trellis:
   • Check Stability: Ensure the trellis system is still firmly anchored and hasn't shifted during winter freezes/thaws or strong winds. Re-secure any loose posts or connections.
   • Assess Damage: Look for any damage to the trellis material (cracked wood, rusted metal, broken plastic) and repair or replace as needed.
2. Manage Climber Emergence:
   • Guide New Growth: As climbing plants emerge from dormancy or put out new shoots, gently guide them onto the trellis. Loosely tie new stems to the support with plant Velcro ties or soft twine.
   • Prune Dead/Damaged Climber Stems: Remove any winter-killed or damaged portions of the climbing plant.
3. Perennial Care:
   • Cleanup: Remove any remaining dead foliage from herbaceous perennials.
   • Fertilize: Apply a balanced fertilizer to the entire bed to support both the emerging perennials and the climbing plant.
   • Divide (if needed): Divide overcrowded perennials before significant new growth, ensuring they have ample space around the trellis.

Summer Maintenance:

1. Train and Tie Climber:
   • Continuous Guidance: As the climbing plant grows vigorously, continue to gently guide its new stems onto the trellis system, weaving them through the supports or tying them loosely. This ensures good coverage and prevents tangling or overwhelming nearby perennials.
   • Pruning: Prune any unruly or overly aggressive growth from the climber that might shade out or smother the perennials, unless that's your intent for shade.
2. Watering and Fertilizing:
   • Consistent Moisture: Both climbers and perennials need consistent watering, especially during dry spells. Plants near a trellis might dry out faster due to increased airflow or competition. Use a soil moisture meter to check.
   • Supplemental Feeding: Continue to fertilize both climbers and perennials according to their needs during peak growth.
3. Pest and Disease Monitoring:
   • Regularly inspect both plants for pests (aphids, spider mites) and diseases (powdery mildew, rust). Address issues promptly to prevent spread. Good air circulation facilitated by training on the trellis helps, but vigilance is still needed.

Fall Maintenance:

1. Perennial Preparation for Winter:
   • Cut Back: For herbaceous perennials, cut back their foliage after it has yellowed or been killed by frost.
   • Mulch: Apply a protective layer of winter mulch around the base of perennials for insulation.
2. Climber Pruning (if applicable):
   • Deciduous Climbers: Prune back non-woody or dead stems of deciduous climbers. For woody climbers (like roses or wisteria), perform any necessary structural or restorative pruning.
   • Clean Up: Remove any fallen leaves or plant debris from around the base of the trellis and perennials to reduce overwintering sites for pests and diseases.

Winter Maintenance:

1. Structural Check: If the trellis system is exposed, check its stability after heavy snow or ice. Remove excessive snow load from the trellis if it seems stressed.
2. Aesthetic Appeal: Appreciate the architectural form of the trellis in the winter landscape.

By following this seasonal maintenance schedule, you ensure your trellis system remains a sturdy support and your overwinter perennials thrive year after year, contributing to a vibrant and evolving garden display.