The use of Trichocereus in bioarchitecture and modern landscaping

# The Use of Trichocereus in Bioarchitecture and Modern Landscaping

**Trichocereus** (treated by some authors as part of *Echinopsis*) are South American columnar cacti of great value for **bioarchitecture** and **contemporary landscaping** due to their sculptural form, rapid growth, low water demand, and extraordinary adaptability. At TRICHOLAND, we select clonal lines for professional production aimed at public works, intensive green roofs, xerophytic gardens, and low-maintenance projects.

This technical article compiles criteria for species selection, design, and compatibility with bioclimatic architecture, as well as recommendations for substrates, irrigation, nutrition, installation, and plant health, with data corroborated in literature and standards of sustainable gardening (xeriscaping, green roofs, and environmental certifications).

Why Trichocereus in Bioarchitecture

• →**Water Efficiency**: CAM physiology with very limited daytime transpiration and high drought tolerance. In xeriscaping strategies, replacing lawns and mesophytic masses with xerophytes can significantly reduce irrigation consumption (technical literature reports reductions of up to ~60% compared to conventional gardens in arid climates, forming the basis for outdoor water reduction credits in programs like LEED).

• →**Ecosystem Services**: They contribute to mitigating the *urban heat island* effect through shading and evaporative cooling of the substrate. In green roofs, vegetation and substrate lower roof surface temperatures and improve the thermal balance of the building; recent analyses document significant average decreases in summer surface temperatures when appropriate vegetation is implemented.

• →**Architectural Form**: Columns of 2–6 m (and more in the ground) that provide verticality and sculptural structure with a low maintenance footprint. Large, fragrant, white nocturnal flowers, of high sensory value in patios and terraces.

• →**Low Maintenance and Safety**: Very limited pruning needs and great longevity. Species/variants with higher spination are useful as *deterrent hedges* without energy or mechanical expenditure.

• →**Resilience**: They tolerate winds, rocky soils, and high radiation. With proper drainage management, they withstand episodes of intense rain without loss of integrity.

Selection of Species and Clones for the Project

The choice depends on climate, available structural load, aesthetics, and functionality. Key botanical references indicate that several species/varieties of *Trichocereus* are vigorous, with marked ribs and large white nocturnal flowers; at the project level, we work with these lines:

• →**Trichocereus macrogonus var. pachanoi** (syn. *T. pachanoi*, *Echinopsis pachanoi*): stems 6–15 cm in diameter and 6–8 ribs; short or nearly spineless spination in selected cultivars. Usual height 3–6 m; large white flowers (19–24 cm), very fragrant and nocturnal. Recommended for patios, entrances, residential and corporate gardening.

• →**T. macrogonus (var. macrogonus)** and **T. peruvianus** (related forms): similar form, often more spiny and with a more glaucous tone; suitable for architectural hedges and compositional axes.

• →**T. bridgesii** (syn. *Echinopsis lageniformis*): cylindrical segments, often with more pronounced spines; interesting for deterrent edges and contrasted compositions.

• →**T. spachianus** and **T. terscheckii**: widely used in landscaping for their monumentality and hardiness. *T. terscheckii* stands out for its superior cold tolerance within the group (reports of brief resistance down to ~−6/−9 °C in dry conditions depending on origin and management), useful in marginal climates.

**Indicative USDA Zones**

• →**T. pachanoi / macrogonus**: 9a–11 (brief episodes ~−3 to −6 °C in mature and dry specimens; avoid wet soils during frost).

• →**T. spachianus / bridgesii**: 9a–10b depending on clone.

• →**T. terscheckii**: 8b–10a with expert management and in dry conditions; protection during persistent frosts.

Applications in Architecture and Landscape

1) Contemporary Xerophytic Gardens

• →**Composition**: columns of Trichocereus as the vertebrae of the design, combined with *Agave*, *Dasylirion*, xerophytic grasses, *Tephrocactus*, local rocks, and gravels. Rhythm through 3-5-3 modules and center-to-center distances of 0.8–1.2 m in medium calibers.

• →**Function**: sculptural hedges, privacy screens, perspective axes. In pedestrian transit edges, prioritize low-spination clones or set back 40–60 cm.

• →**Irrigation**: deep and spaced drip with 2 L/h emitters (1–2 per plant) and seasonal programming based on evapotranspiration.

2) Green Roofs and Terraces

• →**Typology**: only in **intensive roofs** or structural planters; recommended useful depth ≥30–60 cm for medium columns, with very light and draining substrate. Extensive roofs (2–12 cm) are not suitable for columns except in juvenile formats in containers.

• →**Benefits**: contribute to thermal insulation and reduction of surface temperature; the combination of plant substrate and live cover is key in mitigating overheating.

• →**Load**: design with structural engineering. Use lightweight substrates (pumice, expanded clay, lava) to reduce saturated load. A 200 L planter can exceed 300–400 kg once hydrated; plan for drainage, anti-root membranes, and overflow.

• →**Irrigation and Control**: drip lines with 360° rings per plant, moisture sensors in substrate, and water temperature cut-off during heat waves.

3) Roadside Landscaping and Public Spaces

• →**Islands, roundabouts, and slopes**: excellent performance in mineraloid soils, full exposure, and autonomous drip irrigation. Minimal maintenance and high survival rates.

• →**Deterrent Barriers**: more spiny species (e.g., typical *macrogonus*, *bridgesii*) for perimeters with safety setbacks.

Technical Cultivation Specifications for Projects

Substrates (civil works, container, and roof)

• →**Objective**: rapid drainage, high aeration, moderate retention, and low bulk density.

• →**Typical Mix**:

• →**Soil Beds**: elevate in ridges of 15–30 cm, install anti-contaminant geotextile if there are fine clays and French drainage in flat bottoms.

Planting and Establishment

• →**Timing**: spring–summer with stable substrate temperature (>15 °C).

• →**Spacing**: 0.8–1.2 m between axes for calibers of 8–12 cm; expand to 1.2–1.6 m for calibers ≥15 cm.

• →**Staking**: fiberglass rod or cane with elastic ties until root consolidation.

• →**Protection**: shading mesh 40–50% for the first 2–3 weeks in locations of extreme irradiance; gradual removal.

Professional Irrigation

• →**Start**: moderate initial watering and re-water when 50–80% of the useful volume has dried.

• →**Seasonal** (warm-dry climate, container 60–100 L):

• →**Water Quality**: EC < 0.75 dS/m preferred. If hard water is present, acidify to pH 5.8–6.2 and alternate with salt washes.

Nutrition

• →**During Active Growth**: 50–100 ppm N per application every 2–4 irrigations with low N and high K solutions (e.g., 3-5-7/4-7-8) and chelated micros. Avoid urea as the main source.

• →**End of Summer**: reduce N, reinforce K and Si for tissue maturation and cold tolerance.

• →**Washing**: abundant clear water every 6–8 weeks to avoid salt accumulation.

Climate and Exposure

• →**Light**: full sun once acclimatized. In protected indoor/outdoor areas, target PPFD 250–400 µmol/m²/s for vigorous maintenance.

• →**Temperature**: optimal 18–30 °C; dormancy below 10–12 °C.

• →**Frost**: occasional tolerance if the substrate is dry, variable by species and clone (see USDA zones above). In projects, plan for drainage and shelter from cold winds.

Compatibilities with Bioarchitecture Strategies

• →**Xeriscaping**: aligned with the reduction of outdoor irrigation required by environmental certifications. Select species adapted to the local climate and design mineral cover to minimize evaporation.

• →**Green Roofs**: Trichocereus works in intensive systems with deep and light substrate; it provides perennial plant mass, shade, and sculptural aesthetics. Integrate with xerophytic ground cover species for soil coverage and thermal control of the substrate.

• →**Heat Mitigation**: vegetation and substrate reduce the temperature of the envelope; locate columns as vegetative *brise-soleil* in patios and rooftops to shade high thermal load surfaces.

• →**Biophilic Design**: large, fragrant white nocturnal flowers in species like *T. pachanoi* enhance the sensory experience in terraces and patios used in the evening.

Plant Health and Maintenance Inspections

• →**Key Pests**: cotton mealybug (aerial and root), red spider mite during heat waves, scales, and thrips. Integrated control with monthly inspection, 70% isopropyl alcohol, and horticultural soaps/oils in rotation; biological control in greenhouses when appropriate.

• →**Diseases**: rots from excess moisture and cold (crown/root). Prevention with drainage, daytime watering in warm periods, and ventilation. Sanitize to healthy tissue and dry cure any injuries.

• →**Physiopathies**: etiolation from insufficient light; sunburn from sudden exposure to full sun (acclimatize); edema from excessive watering with cold substrate.

Best Practices in Projects and Operations

• →**Hygiene**: quarantine incoming material for 3–4 weeks; disinfected tools for pruning.

• →**Safety**: in public transit, use low-spination clones or discreet barriers; signage during work phases.

• →**Data for Specifications**:

Use Cases and Design Schemes

• →**Architectural Hedges**: modules of 3–4 columns of 1.6–2.4 m alternating glaucous and green clones. Screen effect with minimal water consumption.

• →**Premium Arid Patios**: 1–3 large caliber specimens as sculptural focal points, black volcanic gravel, low-angle night light to emphasize ribs and flowers.

• →**Corporate Terraces**: structural planters with 40–60 cm of light substrate, Trichocereus + xerophytic ground covers; sectoral irrigation with moisture control.

Management Calendar (Northern Hemisphere; invest 6 months in Southern Hemisphere)

• →**Mar–Apr**: planting, transplanting, starting irrigation, and light fertilization.

• →**May–Aug**: peak growth; deep irrigation, complete nutrition, weekly phytosanitary controls. Shade juveniles during extreme heat waves.

• →**Sep**: reduce N, check stakes and anchors.

• →**Oct–Nov**: space out irrigations, prepare for dry winter; protect from persistent cold rains.

• →**Dec–Feb**: dormancy; minimal or no watering in cold; monitor root mealybug.

Quick Comparative Sheet (indicative)

• →**T. macrogonus var. pachanoi**: 3–6 m, 6–8 ribs, short spination; fragrant large white nocturnal flower 19–24 cm; USDA 9a–11.

• →**T. macrogonus / peruvianus**: more spines per areole; more glaucous tones; USDA 9a–10b.

• →**T. bridgesii**: stylized column, marked spines; USDA 9a–10b.

• →**T. spachianus**: rustic and widely used in alignments; USDA 9a–10b.

• →**T. terscheckii**: monumental, certain superior cold tolerance; USDA 8b–10a (with management).

Frequently Asked Questions

• →**Do they require a lot of watering?** No. With suitable substrates and well-designed drip irrigation, the consumption is much lower than that of conventional hedges or meadows.

• →**Can they be placed on rooftops?** Yes, in intensive systems and structural planters with load calculations, lightweight substrate, and professional drainage.

• →**Can they withstand frost?** Brief episodes with dry substrate depending on species/clone. In projects with recurrent frost, choose more rustic material and design elevated drainage.

• →**Do they require pruning?** Only for shaping or sanitation. Topping induces branching when seeking plant mass at a certain height.

TRICHOLAND: professional supply and technical support

At TRICHOLAND, we produce **Trichocereus** for construction and retail in homogeneous calibers, with traceability and *low-spine* lines for public spaces. We offer:

• →Wholesale batches in different calibers, mother plants, and rooted cuttings.

• →Customized lightweight substrate mixtures for roofs and planters.

• →Consulting on irrigation calculations, fertigation, selection of clones by climate, and compatibility with local regulations and environmental certification goals.

• →Logistics and phytosanitary documentation according to destination.

Integrating **Trichocereus** into bioarchitecture and modern landscaping allows for the creation of iconic, resilient spaces that are efficient in water use and maintenance. With the correct selection of plant material, substrate, and irrigation, these columns become a high-performance tool for designers and developers seeking contemporary aesthetics and environmental performance.