PRESTONIANUS VAR. 'BIG CURLY'

1. INTRODUCTION

Habitat and Distribution, Native Continent

Chrysalidocarpus prestonianus var. 'big curly' is endemic to Madagascar, specifically found in the Midongy area with historical collection from Mahanoro. The palm thrives in moist forest environments on slight slopes with clay soils derived from laterite at elevations of 50-550 meters. The natural population in the wild is quite limited, with the species being considered vulnerable in its native habitat.

Taxonomic Classification and Species

Scientific Classification:

• Kingdom: Plantae
• Division: Tracheophyta
• Class: Liliopsida
• Order: Arecales
• Family: Arecaceae
• Genus: Chrysalidocarpus (formerly classified as Dypsis)
• Species: C. prestonianus
• Variety: 'big curly'

The taxonomy of this palm has undergone changes. The genus Chrysalidocarpus was previously subsumed under Dypsis, but recent molecular analysis (2022) has led to reclassifying many Dypsis species back to Chrysalidocarpus. This palm represents one of those reclassified species.

Synonyms

Historical scientific names include Dypsis prestoniana and its varieties. The 'big curly' variant has been recognized as a distinct form due to its unique characteristics.

Common Names

• Big Curly Preston Palm
• Preston's Palm (for the regular variety)
• Madagascar Solitary Palm

Expansion of This Palm in the World

The distribution of this palm outside Madagascar is primarily in botanical gardens and private collections of palm enthusiasts. It's a relatively rare palm in cultivation, though gaining popularity among collectors particularly in tropical regions like Florida, Hawaii, and Southern California where it can be grown outdoors. The regular variety was named after Paul Preston, who as president of McDonald's Restaurants in the United Kingdom sponsored Dr. John Dransfield's four-year Madagascar palm project beginning in 1990.

2. BIOLOGY AND PHYSIOLOGY

Morphology

Trunk: Chrysalidocarpus prestonianus var. 'big curly' is a solitary palm with a trunk reaching 4-12 meters in height and 24-40 cm in diameter. It features a basal boss about 15 cm high and 40 cm in diameter. The internodes are 10-15 cm, pale grey-brown, and distally green and smooth, with nodal scars approximately 3.5 cm and pale grey in color.

Leaves: The crown consists of 8-10 leaves arranged spirally, stretching outward and arching gracefully in the distal part. What distinguishes the 'big curly' variety from the regular C. prestonianus are several key features:

1. Mammoth size - three to four times the size of the regular variety, even at the juvenile stage
2. Much curlier and wider pinnae (leaflets)
3. Consistently green coloration (the regular variety often exhibits a two-tone appearance)
4. Better ability to maintain its green color under cultivation

Flower Systems: The inflorescence is interfoliar (emerging among the leaves), erect with spreading or recurved branches. It branches to 3 orders and is approximately 226 x 90 cm in size. The peduncle is about 118 cm long. The palm produces abundant orange fruits when mature.

Life Cycle of Palm Trees

Like other palms, C. prestonianus var. 'big curly' follows a typical life cycle:

1. Seed Stage: Seeds germinate under proper moisture and temperature conditions
2. Seedling Stage: Initial growth is slow as the plant establishes its root system
3. Juvenile Stage: Characterized by rapid leaf production but limited trunk development
4. Mature Vegetative Stage: Trunk elongation begins, leaf size increases
5. Reproductive Stage: Flowering and fruit production begins once the palm reaches maturity
6. Senescence: Eventually declining after many years

Specific Adaptation to Different Climate Conditions

This palm is adapted to the tropical climate of Madagascar, preferring:

• Warm temperatures year-round
• High humidity
• Seasonal rainfall patterns
• Protection from strong winds
• Moist but well-drained soils

It has limited cold tolerance with a hardiness zone of approximately 9b, meaning it can handle temperatures only down to about 25-30°F (-4 to -1°C) with protection. The 'big curly' variety is noted for its ability to maintain better color under various growing conditions compared to the regular variety.

3. REPRODUCTION AND PROPAGATION

Seed Reproduction

Propagation of Chrysalidocarpus prestonianus var. 'big curly' is primarily through seeds, as the palm does not produce offshoots.

Seed Morphology and Diversity

Seeds are relatively large, approximately 0.25 inches in length. They have a hard outer coating protecting the embryo inside.

Detailed Seed Collection and Viability Testing

Seeds should be collected when fruits turn orange or reddish, indicating maturity. Viability can be tested through:

• Visual inspection (plump, undamaged seeds)
• Float test (viable seeds typically sink in water)
• Cut test (examining the interior for healthy embryo)

Pre-germination Treatments

Seeds benefit from:

• Scarification to break the hard outer coating
• Soaking in warm water (86°F/30°C) for 2-4 days to soften the seed coat
• Removal of any fruit pulp to prevent fungal growth

Step-by-step Germination Techniques

1. Prepare a germination medium of light peat soil or a mix of peat and perlite
2. Plant seeds approximately 1/2 inch deep
3. Maintain consistent temperature between 68-77°F (20-25°C)
4. Keep soil evenly moist but not waterlogged
5. Provide bright, indirect light

Germination Difficulty

Germination of this palm is considered moderately difficult due to:

• Inconsistent germination rates
• Extended germination time
• Specific temperature and moisture requirements

Germination Time

Seeds typically take 3-4 months to germinate, though some may take longer. Patience is required as germination can be sporadic.

Seedling Care and Early Development Stages

Once seedlings emerge:

1. Maintain consistent moisture but avoid overwatering
2. Provide bright, indirect light (morning sun is beneficial)
3. Protect from drafts and temperature fluctuations
4. Transplant into individual containers when the first true leaf appears
5. Use a well-draining, slightly acidic soil mix

Advanced Germination Techniques

For improved germination results:

• Bottom heat (75-80°F/24-27°C) can improve germination percentage
• Maintaining high humidity using clear plastic covers or bags
• Use of fungicides to prevent damping-off

Hormonal Treatments for Germination Enhancement

In some cases, plant growth regulators can be used:

• Gibberellic acid (GA3) at low concentrations may improve germination rates
• Commercial seed primers containing beneficial microorganisms

4. CULTIVATION REQUIREMENTS

Light Requirements

Species-specific Light Tolerance Ranges

Chrysalidocarpus prestonianus var. 'big curly' prefers:

• Bright, filtered light
• Morning sun with afternoon shade in warmer regions
• Protection from intense midday sun that can scorch leaves
• In temperate regions, full sun can be tolerated if properly acclimated

Seasonal Light Variations and Management

• During summer, additional shade may be needed to prevent leaf burn
• Winter light is generally beneficial for maintaining growth
• When grown indoors, provide the brightest position possible without direct sunlight

Artificial Lighting for Indoor Cultivation

When grown indoors:

• High-output LED grow lights with full spectrum
• 12-14 hours of supplemental lighting daily
• Placement within 12-24 inches of foliage
• Rotating the plant regularly for even growth

Temperature and Humidity Management

Optimal Temperature Ranges

• Ideal daytime temperatures: 75-85°F (24-29°C)
• Ideal nighttime temperatures: 65-75°F (18-24°C)
• Growth slows below 60°F (15°C)
• Damage can occur below 40°F (4°C)

Cold Tolerance Thresholds

• The palm is classified in USDA Hardiness Zone 9b
• Can tolerate brief exposure to temperatures around 25-30°F (-4 to -1°C)
• Protection required when temperatures approach freezing
• Cold damage first appears as discoloration on leaflets

Humidity Requirements and Modification Techniques

This palm thrives in:

• Moderate to high humidity (50-80%)
• When grown indoors or in dry climates, humidity can be increased through:
  • Regular misting
  • Use of humidifiers
  • Grouping plants together
  • Pebble trays filled with water

Soil and Nutrition

Ideal Soil Composition and pH Values

The ideal growing medium includes:

• Well-draining soil mix (30% minimum lava rock is recommended for container cultivation)
• Slightly acidic to neutral pH (6.0-7.0)
• Rich in organic matter
• When planting in the ground, plant on a mound with rocks to ensure proper drainage

Nutrient Requirements Through Growth Stages

• Seedlings: Diluted balanced fertilizer monthly
• Juvenile palms: Balanced palm fertilizer with micronutrients quarterly
• Mature palms: Slow-release palm fertilizer with extra potassium and magnesium 2-3 times yearly

Organic vs. Synthetic Fertilization Approaches

Both approaches can be effective:

• Organic: Compost, worm castings, fish emulsion, and seaweed extracts provide slow-release nutrition
• Synthetic: Palm-specific formulations with proper micronutrients ensure balanced nutrition
• A combination approach often yields best results

Micronutrient Deficiencies and Corrections

Common deficiencies and solutions:

• Magnesium deficiency (yellowing leaves): Apply Epsom salts (magnesium sulfate)
• Manganese deficiency (frizzled new growth): Apply manganese sulfate
• Potassium deficiency (spotting on older leaves): Apply potassium sulfate
• Iron deficiency (yellowing with green veins): Apply iron chelates

Water Management

Irrigation Frequency and Methodology

• Water when the top 1-2 inches of soil becomes dry
• Deep, thorough watering is preferable to frequent shallow watering
• Reduce watering during cooler months
• Increase during hot, dry periods
• Drip irrigation or soaker hoses are ideal for outdoor specimens

Drought Tolerance Assessment

The palm has moderate drought tolerance once established, but:

• Extended drought will cause stress and growth reduction
• Young plants have lower drought tolerance than established specimens
• Recovery from severe drought may be slow and incomplete

Water Quality Considerations

• Low salt content is preferable (less than 1000 ppm dissolved solids)
• Chlorine and fluoride can cause leaf tip burn
• If using tap water, allow it to sit overnight before use
• Rainwater or distilled water is ideal for container specimens

Drainage Requirements

Proper drainage is critical:

• Use containers with adequate drainage holes
• For landscape planting, ensure soil drains well after rain
• Avoid areas with standing water
• When planting in containers, use a coarse layer at the bottom for improved drainage

5. DISEASES AND PESTS

Common Problems in Growing

Chrysalidocarpus prestonianus var. 'big curly' can face several challenges in cultivation:

• Leaf spot diseases in humid conditions
• Root rot in poorly drained soils
• Nutritional deficiencies causing discoloration
• Cold damage in marginal climates
• Transplant shock when moved

Identification of Diseases and Pests

Diseases

• Leaf Spot Fungi: Circular to elongated brown spots, possibly with yellow halos
• Bud Rot: Discoloration and decay of the newest growth
• Root Rot: Yellowing foliage, wilting, stunted growth, and decaying roots
• Phytoplasma Disease: Yellowing fronds, stunted growth, spread by planthoppers

Pests

• Scale Insects: Small bumps on leaves and stems that may be followed by sooty mold
• Spider Mites: Fine webbing and stippling on leaves, most common in dry conditions
• Mealybugs: White, cottony masses in leaf axils
• Palm Aphids: Small insects feeding on new growth
• Palm Leaf Skeletonizers: Caterpillars that consume leaf tissue between veins

Environmental and Chemical Protection Methods

Environmental Controls

• Maintain proper spacing for air circulation
• Avoid overhead irrigation to prevent fungal issues
• Proper sanitation, removing dead fronds promptly
• Regular inspection for early detection of problems
• Introducing beneficial insects for pest management

Chemical Controls

• Horticultural oils for scale insects and mites
• Insecticidal soaps for soft-bodied pests
• Copper-based fungicides for leaf spot diseases
• Systemic fungicides for severe fungal infections
• Targeted pesticides only when necessary and following label directions

6. INDOOR PALM GROWING

Specific Care in Housing Conditions

When grown indoors, special considerations include:

• Placement near east or south-facing windows for adequate light
• Rotation of the plant regularly to ensure even growth
• Protection from heating and air conditioning vents
• Use of humidifiers or pebble trays to increase humidity
• Regular cleaning of leaves to remove dust
• Use of containers with proper drainage
• Monitoring for pests that thrive in indoor conditions

Replanting and Wintering

Replanting

• Repot when roots begin circling the container
• Choose a pot only 2-3 inches larger than the current container
• Use fresh, well-draining palm soil mix
• Water thoroughly after repotting
• Place in filtered light until established

Wintering

• Move indoor palms away from cold windows
• Reduce watering frequency but maintain humidity
• Avoid fertilizing during winter months
• Provide supplemental lighting if natural light is insufficient
• Maintain minimum temperatures above 60°F (15°C)
• Resume normal care in spring as growth increases

7. LANDSCAPE AND OUTDOOR CULTIVATION

Establishment and Maintenance in Landscapes

Planting Techniques for Success

• Select a location with filtered light or morning sun
• Plant on a slight mound to ensure drainage
• Mix 30% lava rock into the planting soil
• Maintain adequate spacing (10-15 feet from other large plants)
• Apply 2-3 inches of mulch, keeping it away from the trunk
• Water deeply after planting and regularly until established

Long-term Maintenance Schedules

• Remove old fronds as they die naturally
• Fertilize 2-3 times per year with palm-specific fertilizer
• Monitor for nutritional deficiencies
• Inspect regularly for pest and disease issues
• Prune surrounding vegetation to maintain air circulation
• Adjust irrigation based on seasonal needs

8. COLD CLIMATE CULTIVATION STRATEGIES

Cold Hardiness

According to the available information, this palm is classified as USDA Hardiness Zone 9b, meaning it can tolerate minimum temperatures of approximately 25-30°F (-4 to -1°C) with protection. It's considerably less cold-hardy than some other palm species, requiring protection during frost events.

Winter Protection

In marginal climates, winter protection includes:

• Anti-transpirant sprays to reduce moisture loss
• Wrapping the trunk with insulating materials
• Covering the crown during freeze events
• Christmas lights wrapped around the trunk for added warmth
• Irrigation before a freeze to increase soil heat capacity
• Mulching heavily around the root zone

Hardiness Zone

USDA Zone 9b is recommended as the minimum for landscape cultivation. In colder zones (8-9a), this palm should be grown in containers and moved to protected areas during winter.

Winter Protection Systems and Materials

For landscape specimens in marginal zones:

• Construct temporary frames covered with frost cloth
• Use specialized palm coats designed for winter protection
• Apply mulch deeply around the base
• Install wind breaks on the north and west sides
• String incandescent lights through the canopy for heat
• Temporary heating sources during extreme events

FINAL SHORT SUMMARY

Chrysalidocarpus prestonianus var. 'big curly' is a distinctive solitary palm endemic to Madagascar, characterized by its mammoth size (3-4 times larger than the regular variety), curlier and wider pinnae, and consistently green coloration. This palm thrives in warm, humid environments with temperatures between 65-85°F (18-29°C), bright filtered light, and well-draining, slightly acidic soil. Propagation occurs through seeds, which take 3-4 months to germinate under ideal conditions. It has moderate drought tolerance once established but limited cold hardiness (USDA Zone 9b), requiring protection when temperatures approach freezing. Common problems include leaf spot diseases in humid conditions, root rot in poorly drained soils, and susceptibility to scale insects and spider mites. Whether grown outdoors in suitable climates or as an indoor specimen, this rare and elegant palm makes a striking addition to tropical landscapes and collections, though its vulnerable conservation status in the wild underscores the importance of sustainable cultivation practices.