Chrysalidocarpus carlsmithii (Stumpy Palm)

1. Introduction

Habitat and Distribution

Chrysalidocarpus carlsmithii is a palm species native to Madagascar, specifically found in the northeastern region of the island. This rare palm is known to exist in only two protected sites in the wild: Masoala National Park and the Analalava Reserve near Foulpointe, Toamasina. In its natural habitat, it grows in tropical lowland forests, adapting to the unique environmental conditions of Madagascar's eastern coast.

Taxonomic Classification

• Kingdom: Plantae
• Division: Tracheophyta
• Class: Liliopsida
• Order: Arecales
• Family: Arecaceae
• Genus: Chrysalidocarpus (formerly classified under Dypsis)
• Species: C. carlsmithii

Synonyms

• Dypsis carlsmithii (J.Dransf. & Marcus)

Common Names

• Stumpy Palm
• Carlsmith's Palm

Expansion of this Palm in the World

Originally discovered on the Hawaii estate of former International Palm Society President Donn Carlsmith, this palm remained a mystery for some time as its wild origins were unknown. It was scientifically described in 2012, relatively late compared to many other palm species. Despite its critically endangered status in the wild (with fewer than 15 plants known to exist naturally), Chrysalidocarpus carlsmithii has gained popularity in cultivation, particularly in tropical and subtropical regions like Hawaii, Florida, California, and Australia. Its attractive form and relatively good cold tolerance have contributed to its increasing presence in ornamental landscaping.

2. Biology and Physiology

Morphology

Stem/Trunk

Chrysalidocarpus carlsmithii is a solitary palm with a robust, sturdy trunk that can reach 6-12 meters (20-40 feet) in height. The trunk is particularly thick, typically measuring about 51 cm (20 inches) in diameter at breast height, gradually tapering to about 40 cm near the crownshaft. This substantial girth gives the palm its "stumpy" appearance and common name. The internodes are relatively short, approximately 10 cm long, creating closely spaced leaf scars that contribute to its ornamental appeal. The trunk has a green to grayish-brown coloration that develops as the palm matures.

Leaves

The leaves of C. carlsmithii are pinnate (feather-like) and arching, creating an attractive crown at the top of the trunk. Mature leaves are curved with a slight twist. The leaf sheath is substantial, reaching about 140 cm long and 80 cm wide when opened, with a coloration that ranges from reddish-brown on the adaxial (upper) surface to green or mid-brown on the abaxial (lower) surface. The petiole (leaf stalk) is approximately 45 cm long and 9-12 cm wide. The overall leaf structure contributes to the palm's distinctive silhouette and aesthetic value in landscape settings.

Crownshaft

One of the most distinctive features of C. carlsmithii is its attractive orangey crownshaft (the tubular structure formed by leaf bases above the trunk). This colorful feature adds significant ornamental value to the palm and helps distinguish it from similar species.

Flower Systems

The inflorescence (flower structure) of C. carlsmithii emerges among the leaves (interfoliar) and bears numerous small flowers. The palm produces staminate (male) and pistillate (female) flowers. Staminate flower buds are approximately 3.2 × 2.2 mm with rounded-triangular sepals and petals about 2.8 × 1.8 mm. The pistillate flowers are smaller with sepals around 1.5 × 1.5 mm. After successful pollination, the palm produces irregularly ovoid-ellipsoid fruits measuring about 16 × 9 mm, with black epicarp (outer skin) when ripe.

Life Cycle

Like most palms, Chrysalidocarpus carlsmithii follows a typical monocot life cycle, beginning as a seed that germinates to produce a seedling with a single leaf (eophyll). The palm then progresses through a juvenile stage characterized by increasing leaf size and complexity before reaching maturity. C. carlsmithii is known to be a slow-growing palm, particularly in its early stages, which contributes to its value as a landscape specimen as it maintains an attractive form for many years. Once mature, the palm flowers and, if pollinated, produces fruits containing seeds that can give rise to new individuals.

Specific Adaptations to Different Climate Conditions

C. carlsmithii has demonstrated surprising adaptability to various climate conditions outside its native tropical habitat:

• Cold Tolerance: Despite originating from tropical Madagascar, this palm has shown notable cold hardiness. In midstate Florida, even still-stemless young specimens have been reported to withstand freezes with minimal damage.

• Drought Resistance: While preferring consistent moisture, established plants can tolerate short periods of drought, making them suitable for various landscape applications in subtropical regions.

• Wind Resistance: The robust trunk and flexible fronds allow the palm to withstand significant wind, an adaptation that serves it well in coastal or exposed planting locations.

These adaptations have contributed to the palm's successful cultivation in regions ranging from tropical Hawaii to subtropical Florida and even in protected locations in Southern California.

3. Reproduction and Propagation

Seed Reproduction

Seed Morphology and Diversity

The seeds of Chrysalidocarpus carlsmithii are about 13 × 8 mm in size, with a homogeneous endosperm. This contrasts with some related species that have ruminate endosperm (with a marbled appearance when cut). The embryo is positioned laterally within the seed. The seeds develop within the palm's fruits, which turn black when fully ripe and ready for collection.

Seed Collection and Viability Testing

Seeds should be collected when fruits have turned completely black and are easily removed from the infructescence (fruit cluster). Once collected, the fleshy outer fruit material (mesocarp) should be removed to prevent fungal growth during storage or germination. Viability testing can be performed through flotation (viable seeds generally sink in water) or by cutting a sample seed to examine the endosperm, which should be firm and white in viable seeds.

Pre-germination Treatments

While specific pre-germination treatments for C. carlsmithii are not widely documented due to its relative rarity, general approaches for related Chrysalidocarpus/Dypsis species can be applied:

• Scarification: Light scarification of the seed coat may help improve water penetration and speed germination.
• Heat Treatments: Maintaining seeds at constant warm temperatures (30-35°C/86-95°F) can accelerate the germination process.
• Soaking: Pre-soaking seeds in warm water for 2-4 days before planting can help initiate the germination process.

Step-by-step Germination Techniques

1. Preparation: Clean seeds thoroughly to remove all fruit pulp.
2. Pre-treatment: Soak seeds in warm water (changing daily) for 2-4 days.
3. Planting Medium: Use a well-draining but moisture-retentive medium such as a mixture of peat and perlite, or specialized palm seed starting mix.
4. Planting Depth: Plant seeds with about 1/3 to 1/2 of the seed exposed above the medium.
5. Environment: Maintain consistent warmth (30-32°C/86-90°F) and high humidity, preferably using a propagation chamber or sealed plastic bag.
6. Moisture: Keep the growing medium consistently moist but not waterlogged.
7. Light: During the germination phase, bright indirect light is preferable to direct sunlight.

Germination Difficulty

Chrysalidocarpus carlsmithii is considered moderately difficult to germinate compared to some other palm species. Factors contributing to this include its relatively slow germination process and specific temperature requirements. Fresh seeds typically show higher germination rates than stored seeds.

Germination Time

Based on data from related Chrysalidocarpus/Dypsis species, germination time for C. carlsmithii can range from 1-3 months under optimal conditions, though some seeds may take up to 6 months to germinate. The variability in germination time makes patience an essential virtue for propagators of this species.

Seedling Care and Early Development Stages

Once germinated, seedlings require careful attention:

1. Light: Gradually increase light exposure but avoid harsh direct sunlight until seedlings have developed several leaves.
2. Watering: Maintain consistent moisture without overwatering, allowing the surface to dry slightly between waterings.
3. Humidity: Maintain higher than ambient humidity for the first few months.
4. Fertilization: Begin with very dilute balanced fertilizer after the first true leaf has fully expanded.
5. Protection: Shield young seedlings from pests, especially mites and scale insects, which can devastate young plants.

Seedlings develop slowly initially, with new leaves becoming progressively larger and more complex. The juvenile stage may last several years before trunk development becomes evident.

Advanced Germination Techniques

For improved germination success, advanced techniques may include:

• Controlled Environment Chambers: Using precisely controlled temperature and humidity chambers to optimize germination conditions.
• Bottom Heat: Applying gentle bottom heat (30-32°C/86-90°F) to germination containers to stimulate root development.
• Fungicide Treatment: Applying fungicidal treatments to seeds and germination media to prevent damping off and other fungal problems common in palm seedling production.

Hormonal Treatments for Germination Enhancement

While not extensively documented for C. carlsmithii specifically, these approaches may be beneficial:

• Gibberellic Acid (GA3): Application of GA3 at low concentrations (50-100 ppm) may help break seed dormancy and promote more uniform germination.
• Cytokinins: In some palm species, cytokinin treatments have shown promise in promoting germination, though this requires further study for C. carlsmithii.

4. Cultivation Requirements

Light Requirements

Species-specific Light Tolerance Ranges

Chrysalidocarpus carlsmithii demonstrates adaptability across a range of light conditions, though it performs best with bright, filtered light. While mature specimens can tolerate full sun in cooler climates, they generally prefer protection from intense midday sun in very hot regions. Young plants require more protected light conditions than established specimens.

Seasonal Light Variations and Management

In seasonally variable climates, light management for C. carlsmithii should adapt to annual changes:

• Summer: In hot summer regions, providing afternoon shade helps prevent leaf scorching while still allowing sufficient light for healthy growth.
• Winter: During winter months with lower light intensity, maximizing available light becomes important, especially for indoor cultivation.
• Transitional Seasons: Spring and fall typically present ideal light conditions for this palm in most climates, requiring minimal intervention.

Artificial Lighting for Indoor Cultivation

When grown indoors, C. carlsmithii benefits from supplemental lighting:

• Light Type: Full-spectrum LED grow lights are most effective, providing the balanced light spectrum needed for healthy growth.
• Duration: 12-14 hours of artificial light daily helps maintain vigor during indoor cultivation.
• Placement: Lights should be positioned approximately 30-36 inches above the palm crown to prevent heat damage while providing adequate intensity.

Temperature and Humidity Management

Optimal Temperature Ranges

C. carlsmithii thrives within specific temperature parameters:

• Optimal Growth Range: 24-32°C (75-90°F) for maximum growth and development.
• Tolerance Range: Can survive short periods between 10-38°C (50-100°F) with minimal stress.
• Critical Threshold: Damage typically occurs below 5°C (41°F) or above 40°C (104°F).

Cold Tolerance Thresholds

While originally from tropical Madagascar, C. carlsmithii has shown surprising cold tolerance:

• Brief Exposure: Can withstand brief exposures to near-freezing temperatures when mature.
• Extended Cold: Extended periods below 10°C (50°F) can stress the palm, particularly if combined with wet conditions.
• Frost Protection: In marginal climates, frost cloth protection during freeze events can prevent damage to fronds and growing point.

Humidity Requirements and Modification Techniques

As a tropical species, C. carlsmithii prefers moderate to high humidity levels:

• Optimal Range: 50-80% relative humidity promotes the best growth and appearance.
• Adaptability: Can adapt to lower humidity (30-50%) but may show cosmetic leaf tip browning.
• Modification Methods: For indoor cultivation, humidity can be increased through the use of humidifiers, grouping with other plants, or placement on humidity trays.

Soil and Nutrition

Ideal Soil Composition and pH Values

Chrysalidocarpus carlsmithii performs best in specific soil conditions:

• Soil Texture: Well-draining, slightly sandy loam with good organic content.
• pH Range: Slightly acidic to neutral (6.0-7.0) is ideal.
• Structure: Soil should have good aeration while retaining some moisture.
• Components: A typical optimal mix might include 40% quality topsoil, 30% coarse sand or perlite, and 30% organic matter such as composted pine bark or coconut coir.

Nutrient Requirements Through Growth Stages

Nutritional needs vary throughout the palm's development:

• Seedling Stage: Low fertilizer concentrations (1/4 strength) of balanced formula (e.g., 10-10-10) applied monthly.
• Juvenile Stage: Moderate fertilizer applications (1/2 strength) of palm-specific formula (e.g., 8-2-12 with micronutrients) every 2-3 months.
• Mature Stage: Regular applications of palm-specific fertilizer following label recommendations, typically 3-4 times per year.

Organic vs. Synthetic Fertilization Approaches

Both fertilization approaches have merits for C. carlsmithii cultivation:

• Organic Options: Composted manure, seaweed extracts, fish emulsion, and bone meal provide slow-release nutrition that improves soil structure.
• Synthetic Options: Controlled-release formulations like Osmocote® Palm or water-soluble palm-specific fertilizers provide precise nutrient ratios and release timing.
• Hybrid Approach: Many growers achieve best results by combining organic soil amendments for long-term soil health with occasional synthetic fertilizers for targeted nutrition.

Micronutrient Deficiencies and Corrections

C. carlsmithii, like many palms, is prone to specific micronutrient issues:

• Magnesium Deficiency: Yellowing of older fronds while veins remain green; corrected with magnesium sulfate (Epsom salt) applications.
• Manganese Deficiency: New leaves emerge with yellow flecking or mottling; treated with manganese sulfate foliar sprays.
• Iron Deficiency: Young leaves develop interveinal chlorosis (yellowing between green veins); addressed with chelated iron applications.
• Boron Deficiency: Deformed new growth with "accordion-leaf" appearance; corrected with careful application of borax or boron-containing micronutrient mix.

Water Management

Irrigation Frequency and Methodology

Proper watering is critical for C. carlsmithii health:

• Establishment Phase: Frequent, generous watering (2-3 times weekly) for the first 3-6 months after planting.
• Established Plants: Moderate watering (once weekly in warm weather) allowing soil to dry slightly between waterings.
• Seasonal Adjustments: Reduced frequency in winter or cooler months, increased during hot, dry periods.
• Methods: Drip irrigation or soaker hoses are preferable to overhead sprinklers, which can promote fungal issues in the crown.

Drought Tolerance Assessment

C. carlsmithii demonstrates moderate drought tolerance:

• Short-term Drought: Can withstand 2-3 weeks of dry conditions once established with minimal stress.
• Long-term Drought: Extended dry periods (1+ months) will cause stress, leaf browning, and potential long-term damage.
• Recovery Capacity: Generally recovers well from moderate drought with renewed irrigation, though severe drought may cause permanent damage to older fronds.

Water Quality Considerations

Water quality significantly impacts C. carlsmithii health:

• Chlorine/Chloramine: High levels in municipal water may cause leaf tip burn; allowing water to stand 24 hours before use allows chlorine (but not chloramine) to dissipate.
• Salinity: Low tolerance for salt; water with EC > 1.0 mS/cm may cause leaf margin burn.
• pH: Irrigation water with pH between 5.5-7.5 is ideal; highly alkaline water may require acidification.
• Temperature: Cold irrigation water can shock roots; water temperature should ideally be similar to soil temperature.

Drainage Requirements

Proper drainage is essential for C. carlsmithii cultivation:

• Container Culture: Pots must have ample drainage holes and 1-2 inches of drainage material in the bottom.
• Landscape Planting: Avoid low spots where water collects; consider raised planting beds in poorly-draining locations.
• Inspection: Regularly check that drainage remains functional, especially in container culture where drain holes can become blocked.

5. Diseases and Pests

Common Problems in Growing

Chrysalidocarpus carlsmithii faces several challenges in cultivation:

• Root Rot: Often caused by overwatering or poor drainage, resulting in yellowing fronds and eventual decline.
• Nutrient Deficiencies: Particularly manganese and potassium, manifesting as frond discoloration and deformities.
• Environmental Stress: Cold damage or sunburn can cause lasting cosmetic damage to fronds.
• Transplant Shock: Sensitivity to root disturbance can cause temporary decline after replanting.

Identification of Diseases and Pests

Common Diseases

C. carlsmithii can be affected by several pathological conditions:

• Ganoderma Butt Rot: Fungal infection at the trunk base, often fatal. Identified by conks (shelf-like fungal bodies) emerging from the lower trunk and internal trunk decay.
• Lethal Yellowing: Phytoplasma disease transmitted by planthoppers, causing progressive yellowing from lower to upper fronds, flower abortion, and eventually death.
• False Smut: Fungal infection causing black pustules on fronds, typically more cosmetic than lethal.
• Leaf Spot Diseases: Various fungal pathogens causing spotting or lesions on fronds, particularly in humid conditions with poor air circulation.

Insect Pests

Several arthropod pests commonly affect C. carlsmithii:

• Spider Mites: Tiny arachnids causing stippling and discoloration on frond undersides, particularly problematic in dry conditions.
• Scale Insects: Both armored and soft scales may infest fronds and stems, causing yellowing and decline through sap extraction.
• Mealybugs: White, waxy insects that collect in leaf axils and under frond bases, weakening the palm through sap feeding.
• Palm Aphids: Small, soft-bodied insects that cluster on new growth, causing distortion and honeydew secretion.

Environmental and Chemical Protection Methods

Cultural Controls

Preventative practices that reduce disease and pest pressure:

• Proper Spacing: Adequate spacing between palms improves air circulation and reduces pest and disease spread.
• Sanitation: Prompt removal of dead or diseased fronds helps limit pathogen reservoirs.
• Appropriate Irrigation: Watering at the soil level rather than overhead reduces foliar disease incidence.
• Balanced Nutrition: Well-nourished palms have greater natural resistance to pests and diseases.

Biological Controls

Environmentally friendly approaches to pest management:

• Beneficial Insects: Ladybugs, lacewings, and parasitic wasps can help control aphids, mealybugs, and scale insects.
• Microbial Products: Bacillus thuringiensis (Bt) formulations for caterpillar control; beneficial nematodes for soil-dwelling pests.
• Predatory Mites: Introduction of predatory species such as Phytoseiulus persimilis to control spider mites.

Organic Treatments

Low-impact interventions suitable for sustainable management:

• Horticultural Oils: Suffocate insects while causing minimal harm to beneficial species.
• Insecticidal Soaps: Disrupt the cell membranes of soft-bodied insects like aphids and mealybugs.
• Neem Products: Act as both repellent and growth regulator for many insect species.
• Copper Fungicides: Provide protective barrier against many fungal and bacterial pathogens.

Chemical Controls

Conventional treatments for severe infestations or diseases:

• Systemic Insecticides: Products containing imidacloprid or dinotefuran can provide long-term control of sap-feeding insects.
• Contact Insecticides: Pyrethroids or organophosphates for rapid control of visible pests.
• Systemic Fungicides: Propiconazole or azoxystrobin for management of fungal diseases.
• Antibiotic Treatments: Oxytetracycline injections may slow progression of phytoplasma diseases like lethal yellowing.

6. Indoor Palm Growing

Specific Care in Housing Conditions

Successfully growing Chrysalidocarpus carlsmithii indoors requires attention to several factors:

Light Considerations

• Placement: Position near south or west-facing windows for maximum natural light.
• Supplemental Lighting: Consider grow lights if natural light is insufficient, especially during winter months.
• Rotation: Rotate the palm quarterly to promote even growth, as palms will lean toward light sources.

Environmental Controls

• Temperature: Maintain 18-29°C (65-85°F) for optimal growth, avoiding cold drafts and heat vents.
• Humidity: Use humidifiers, pebble trays, or regular misting to maintain 40-60% relative humidity.
• Air Circulation: Provide gentle air movement with fans to prevent fungal issues, but avoid direct drafts.

Container Selection

• Material: Glazed ceramic or plastic containers retain moisture better than terracotta, which may dry too quickly indoors.
• Size: Choose containers only 2-4 inches larger in diameter than the root ball to prevent overwatering issues.
• Drainage: Ensure excellent drainage with multiple holes and elevated container bases to prevent water accumulation.

Indoor Fertilization

• Frequency: Apply at half the recommended outdoor rate, typically every 2-3 months during active growth.
• Formulation: Use slow-release granular fertilizers designed for indoor palms to reduce nutrient leaching.
• Seasonal Adjustment: Reduce or eliminate fertilization during winter when growth naturally slows.

Repotting and Wintering

Repotting Procedures

• Timing: Repot in spring or early summer when the palm is in active growth.
• Frequency: Every 2-3 years for younger specimens, less frequently for mature plants.
• Method:
  1. Pre-water the palm 24 hours before repotting to reduce stress.
  2. Prepare new container with drainage material and fresh potting mix.
  3. Carefully remove palm from old container, disturbing roots minimally.
  4. Position at same depth as previously grown, with top of root ball slightly below container rim.
  5. Backfill with fresh potting mix, gently firming but not compacting.
  6. Water thoroughly after repotting and place in protected location during establishment.

Winter Care

• Light: Move to brightest available location as daylight hours decrease.
• Watering: Reduce frequency by approximately 50%, allowing soil to dry more between waterings.
• Temperature: Maintain minimum temperatures above 15°C (60°F) for optimal health.
• Humidity: Increase humidity efforts during winter heating season when indoor air tends to be drier.
• Pest Monitoring: Increase vigilance for pests like spider mites that thrive in dry indoor winter conditions.

7. Landscape and Outdoor Cultivation

Specific Landscape Uses

Chrysalidocarpus carlsmithii offers versatility in landscape applications:

• Specimen Planting: Its robust form and distinctive appearance make it an excellent standalone focal point.
• Grouping: Small clusters of 3-5 palms create impressive tropical statements in larger landscapes.
• Foundation Planting: The palm's predictable growth habit makes it suitable for placement near structures.
• Privacy Screening: When planted in rows, mature specimens can provide visual screening while maintaining an open, tropical feel.
• Entrance Marking: Often used to flank driveways or entryways, creating a grand tropical impression.

Cold Climate Cultivation Strategies

Cold Hardiness

C. carlsmithii has demonstrated surprising cold tolerance for a Madagascar native:

• Reliable Hardiness: Generally considered hardy in USDA zones 10a and warmer (minimum temperatures above 30°F/-1°C).
• Marginal Zones: Can succeed in protected microclimates of zone 9b with proper site selection and protection.
• Cold Acclimation: Gradual temperature decreases allow the palm to develop better cold tolerance than sudden freezes.

Winter Protection Systems and Materials

For marginal climates, several protection strategies can extend the growing range:

• Temporary Structures: Frame and plastic coverings can create mini-greenhouses around smaller specimens.
• Trunk Wrapping: Insulating materials like frost cloth or burlap wrapped around trunks protect the critical growing point.
• Mulching: Heavy organic mulching around the root zone helps maintain soil warmth during cold periods.
• Anti-desiccant Sprays: Application to fronds can reduce winter desiccation damage in dry, cold climates.
• Heating Cables: For valuable specimens, soil heating cables beneath mulch maintain root zone temperatures.

Establishment and Maintenance in Landscapes

Planting Techniques for Success

Proper planting significantly impacts long-term performance:

1. Site Selection: Choose locations with filtered light (especially afternoon shade in hot climates), good drainage, and protection from strong winds.
2. Planting Hole: Dig hole 2-3 times wider than root ball but only as deep as the root ball height.
3. Soil Amendment: Incorporate 30-40% organic matter into native soil for improved root establishment.
4. Planting Depth: Set palm at same depth as in nursery container, never deeper.
5. Backfilling: Carefully fill around roots, eliminating air pockets without excessive compaction.
6. Basin Formation: Create a watering basin around the newly planted palm.
7. Mulching: Apply 2-3 inches of organic mulch, keeping it several inches away from the trunk.
8. Initial Watering: Thoroughly saturate the root zone after planting.

Long-term Maintenance Schedules

Regular care ensures continued landscape performance:

• Irrigation: Weekly deep watering during first year, transitioning to bi-weekly or monthly for established specimens.
• Fertilization: Apply palm-specific fertilizer 3-4 times annually during growing season.
• Pruning: Remove only dead or damaged fronds; never "hurricane cut" or remove green fronds.
• Mulch Renewal: Refresh organic mulch annually to maintain 2-3 inch depth.
• Pest Monitoring: Inspect quarterly for early detection of pest or disease issues.
• Root Zone Protection: Maintain mulched area and prevent mechanical damage from lawn equipment.

Final Summary

Chrysalidocarpus carlsmithii (Stumpy Palm) represents a remarkable success story in palm conservation through cultivation. Originally discovered in Hawaiian cultivation and only later identified in its native Madagascar (where fewer than 15 wild specimens exist in just two locations), this palm has found a secure future through ornamental horticulture.

Distinguished by its robust trunk that can reach 20-40 feet tall with a substantial 20-inch diameter, C. carlsmithii grows slowly but steadily, developing an attractive orangey crownshaft beneath arching green fronds. Its surprising cold tolerance (surviving freezes in Florida) has expanded its cultivation range beyond tropical regions into subtropical areas.

Although propagation through seeds requires patience with germination taking 1-3 months under optimal conditions, the palm rewards growers with its impressive form and relatively low maintenance requirements once established. It prefers bright, filtered light, well-draining soil with regular moisture, and balanced nutrition.

Whether grown as a dramatic landscape specimen or as a contained indoor palm, Chrysalidocarpus carlsmithii offers distinctive tropical character and architectural value that will continue to ensure its popularity with palm enthusiasts and landscapers alike, ultimately helping preserve this critically endangered species for future generations.