Chamaedorea adscendens

1. Introduction

Habitat and Distribution

Chamaedorea adscendens, commonly known as the Velvet Palm, is native to the forests of Central America, specifically Guatemala (Alta Verapaz, Peten) and Belize (Toledo). It grows at elevations between 200 and 700 meters in moist or wet forests on the Atlantic slope, primarily on solid limestone substrates. The species is not widely distributed, occurring only on infrequent steep hillside locations near summits.

Taxonomic Classification

Kingdom: Plantae
Division: Tracheophyta
Class: Liliopsida
Order: Arecales
Family: Arecaceae
Genus: Chamaedorea
Species: C. adscendens

Synonyms

• Kinetostigma adscendens Dammer (1905)
• Tuerckheimia ascendens Dammer (1905)

Common Names

• Velvet Palm
• Ascending Chamaedorea

Global Distribution

The Chamaedorea genus comprises approximately 107 species of palms native to subtropical and tropical regions of the Americas. While C. adscendens is naturally limited to Central America, it is cultivated worldwide as an ornamental plant, though it remains relatively rare in cultivation compared to other Chamaedorea species like C. elegans (Parlor Palm). The natural population of C. adscendens has become fragmented and reduced due to anthropic pressure, leading to its classification as "vulnerable" (at risk of extinction) on the IUCN Red List.

2. Biology and Physiology

Morphology

Stem

C. adscendens has solitary, erect stems that can reach up to 2.5 meters in height, though they typically grow much slower and smaller in cultivation. The stems are slender, measuring 8-10 mm (0.8-1 cm) in diameter, with a green color. The rings or scars from fallen leaves are prominent and spaced approximately 2-2.5 cm apart on the stem.

Leaves

The leaves are one of the most distinctive features of this palm, being pinnate (rarely bifid, especially in younger specimens). They measure 15-20 cm in length with 2-6 leaflets per side, arranged more or less alternately. The leaflets are obovate-lanceolate with long acuminate tips, measuring 8-16 cm long and 2-3.5 cm wide.

What makes C. adscendens particularly attractive is the texture and color of its leaves, which are coriaceous (leathery), thick (among the thickest in the genus), and possess a velvety texture with a distinctive grey-blue-green or bluish-green color on the upper surface. The leaves grow on a 7-9 cm petiole that is densely dotted with white.

The tubular leaf base wraps the stem completely for about 6 cm, opening obliquely at the apex. It appears grey-green with white dots in the upper part and persists dry for a long time on the stem.

Flower System

C. adscendens is dioecious, meaning male and female flowers occur on separate plants. The inflorescences are infrafoliar (appearing below the leaves) on ascending peduncles that reach 40-60 cm in length. Male specimens produce characteristic yellow inflorescences, while female plants develop flowers that later produce fruits.

Life Cycle

Like all palms, C. adscendens has a monopodial growth pattern with a single growing point. The plant grows slowly, taking many years to reach its maximum height of 2.5 meters. As a dioecious species, both male and female plants are needed for successful sexual reproduction and seed production.

Specific Adaptations

C. adscendens has adapted to grow in the understory of humid forests, thriving in low-light conditions beneath the forest canopy. Its velvety, leathery leaves appear to offer some protection against pests, as it is reported to be more resistant to snails and spider mites than other Chamaedorea species. The species has also adapted to limestone-rich soils in its native habitat, suggesting a preference for alkaline conditions.

3. Reproduction and Propagation

Seed Reproduction

Seed Morphology

C. adscendens produces globose to ovoidal fruits that measure approximately 0.8 cm in diameter. These fruits are initially green, turning glossy black when ripe. Each fruit contains a single globose seed measuring about 0.6 cm in diameter.

Seed Collection and Viability

Seeds should be collected when the fruits are completely ripe or when they naturally fall from the plant. Multiple seeds should be collected as germination can be unreliable. After collection, the fruit tissue and pulp should be removed, and the seeds rinsed thoroughly (wearing gloves is recommended as the pulp can be irritating).

Pre-germination Treatments

Before planting, the seeds should be soaked in water for 1-7 days (changing the water daily), or at minimum, 2 days as recommended for C. adscendens specifically. After soaking, the hard outer seed covering should be filed or nicked to improve germination chances.

Germination Techniques

Seeds should be planted in a well-draining medium, such as a 50-50 mix of peat moss and perlite, or a similar draining loam. The medium should be kept consistently moist but not soggy. The optimal temperature for germination is between 24-26°C (75-79°F), though some sources suggest even warmer conditions of 29-32°C (85-95°F) using a heat mat for best results.

Seeds should be covered with the growing medium to prevent drying out but not planted too deeply. The pot should be placed in shade or partial sunlight, protected from intense direct light to mimic the understory conditions of the palm's natural habitat.

Germination Difficulty and Time

Germination of C. adscendens seeds is considered moderately difficult and can be quite slow, typically taking 2-3 months to begin, though it may extend to several months. Patience is essential when propagating this species from seed.

Seedling Care

Once germination occurs and one or two leaves appear, seedlings should be transplanted to larger pots, being careful not to plant them too deeply. Young plants require consistent moisture, warm temperatures, and protection from direct sunlight.

4. Cultivation Requirements

Light Requirements

C. adscendens prefers shade to partial shade conditions, mimicking its natural understory habitat. It does not tolerate bright direct sunlight well, which can cause leaf burn. In indoor settings, bright indirect light is ideal, while in outdoor settings, filtered light through tree canopies works well.

Temperature and Humidity Management

Optimal Temperature Ranges

The optimal temperature range for C. adscendens is between 18-26°C (65-80°F). While it prefers warm conditions, it can tolerate cooler temperatures for brief periods, though it is not frost-hardy and should be protected when temperatures approach freezing.

Cold Tolerance

C. adscendens has moderate cold tolerance compared to some other palm species. It can withstand temperatures "little less" than its optimal range for short periods, but should be protected from frost and prolonged cold. It is not among the most cold-hardy Chamaedorea species (C. radicalis and C. microspadix are more cold-tolerant).

Humidity Requirements

As a tropical species, C. adscendens appreciates moderate to high humidity. In indoor environments, regular misting or placement on humidity trays can be beneficial, especially during dry winter months. In outdoor cultivation, planting in groups can help create a microclimate with higher humidity.

Soil and Nutrition

Ideal Soil Composition

C. adscendens thrives in well-draining soil rich in organic matter. Given its native habitat on limestone substrates, it benefits from slightly alkaline to neutral pH conditions. A mix containing peat, perlite, and some lime to adjust pH can work well. For container growing, any high-quality, peat-based potting mix that provides good drainage is suitable.

Nutrient Requirements

C. adscendens, like most Chamaedoreas, is a light feeder. During the growing season (spring and summer), it can benefit from monthly applications of a weak liquid fertilizer, preferably with a 3-1-2 or 2-1-2 NPK ratio. No fertilization is needed during the winter dormant period.

Water Management

Irrigation Frequency

Water thoroughly when the top inch of soil feels dry to the touch. During active growth in spring and summer, this might mean weekly watering, while in winter, the frequency can be reduced to once every 2-3 weeks. Overwatering should be avoided as it can lead to root rot.

Drought Tolerance

C. adscendens has been noted to have reasonable drought tolerance, especially for a tropical-looking palm. This adaptability likely stems from the occasional drought conditions in its native habitat. However, consistent moisture is still preferred for optimal growth and appearance.

Drainage Requirements

Good drainage is essential for this species to prevent root rot. When potting, ensure that containers have adequate drainage holes, and consider adding extra perlite or coarse sand to improve drainage in heavier soils.

5. Diseases and Pests

Common Problems

Root Rot

Caused by overwatering or poor drainage, symptoms include blackening of roots, yellowing leaves, and eventual plant death. Prevention includes proper drainage and careful watering practices.

Leaf Spots

Fungal leaf spots can develop in conditions of high humidity combined with poor air circulation. These appear as dark spots on foliage that may expand over time.

Nutrient Deficiencies

Yellowing leaves (particularly older ones) may indicate nitrogen deficiency, while overall pale foliage might suggest general malnutrition.

Identification of Pests

Spider Mites

Though C. adscendens appears to have some resistance to spider mites compared to other Chamaedoreas, these tiny pests can still be problematic, especially in dry indoor environments. Look for fine webbing and stippled, yellowing leaves.

Mealybugs

Appearing as white, cottony masses in leaf axils and on stems, mealybugs suck plant sap and weaken the palm.

Scale Insects

These appear as small bumps on stems and leaves, often brownish or tan in color, and can be difficult to remove once established.

Protection Methods

Environmental Controls

Maintaining appropriate humidity, ensuring good air circulation, and providing optimal growing conditions help prevent many pest and disease issues. Regular inspection of plants allows for early detection and intervention.

Chemical Treatments

For severe infestations, insecticidal soaps or horticultural oils may be applied, following product instructions carefully. Systemic insecticides can be effective for scale and mealybugs but should be used judiciously.

Biological Controls

Predatory insects such as ladybugs can help control aphids and other small pests in outdoor settings.

6. Indoor Palm Growing

Specific Care in Housing Conditions

C. adscendens makes an excellent container specimen for indoor cultivation, where its modest size and attractive foliage can be showcased. Indoor cultivation requirements include:

• Light: Bright indirect light is ideal; avoid direct sunlight which can scorch leaves.
• Temperature: Normal room temperatures of 18-24°C (65-75°F) are suitable.
• Humidity: Regular misting or use of a humidifier helps maintain appropriate humidity, especially in heated indoor environments during winter.
• Watering: Allow the top inch of soil to dry between waterings; reduce frequency in winter.
• Container: Choose a container with good drainage that is proportional to the plant's size.

Repotting and Wintering

Repotting should be done infrequently, as C. adscendens has a relatively weak root system and doesn't appreciate disturbance. Only repot when necessary, using a container no more than 2 inches larger in diameter than the previous one.

During winter, reduce watering frequency and withhold fertilizer. Keep the plant away from cold drafts, heating vents, and radiators which can cause leaf tip burn. If growing in regions with cold winters, ensure the plant is kept in a warm location, ideally above 12°C (54°F).

7. Landscape and Outdoor Cultivation

C. adscendens is particularly effective when planted in groups in landscape settings, creating an elegant understory display beneath larger trees. It works well in tropical and subtropical gardens, adding textural interest with its distinctive velvety foliage.

In landscape settings, it's best positioned in locations that receive filtered light or partial shade, such as beneath tree canopies or on the north or east sides of structures. It pairs well with other shade-loving tropicals such as heliconias, gingers, and ferns.

Establishment and Maintenance in Landscapes

When establishing C. adscendens in landscapes:

1. Site Selection: Choose a location with filtered light, protection from strong winds, and well-draining soil.
2. Soil Preparation: Incorporate organic matter to improve drainage and nutrient content. If soil is acidic, consider adding lime to raise the pH slightly.
3. Spacing: For group plantings, space plants 60-90 cm (2-3 feet) apart to allow for growth while creating a lush effect.
4. Mulching: Apply a layer of organic mulch around (but not touching) the stem to conserve moisture and suppress weeds.
5. Irrigation: Provide regular water during establishment; once established, irrigation can be reduced, though consistent moisture produces the best growth and appearance.
6. Fertilization: Apply a balanced, slow-release fertilizer in spring and mid-summer.
7. Maintenance: Remove dead fronds as needed, cutting them at the base of the stem. Regular monitoring for pests and diseases is advisable.

8. Cold Climate Cultivation Strategies

Cold Hardiness

C. adscendens is not among the most cold-hardy of the Chamaedorea species, with C. radicalis and C. microspadix being more tolerant of cold temperatures. However, it can withstand brief exposure to temperatures approaching freezing if properly acclimated and protected.

Winter Protection

In regions where temperatures regularly drop below 10°C (50°F), protection becomes essential for outdoor plantings:

1. Mulching: Apply a thick layer of mulch around the base of the plant to insulate the root zone.
2. Covering: During frost events, cover plants with frost cloth, bed sheets, or burlap. Ensure covers extend to the ground to trap warmth from the soil.
3. Positioning: Plant in sheltered locations such as against south-facing walls that absorb and radiate heat.
4. Container Cultivation: In colder regions, growing in containers that can be moved indoors or to protected areas during winter is advisable.

Hardiness Zone

C. adscendens is generally suitable for cultivation in USDA Hardiness Zones 10-11, with careful protection potentially extending its range into warm Zone 9b locations. In marginal zones, microclimate selection becomes crucial, with plantings against structures, under tree canopies, or in courtyards offering the best chance of success.

Winter Protection Systems

For established landscape specimens in areas with occasional cold snaps:

1. Temporary Structures: PVC hoops covered with frost cloth can create mini-greenhouses around valuable specimens.
2. Heat Sources: In extreme situations, incandescent (not LED) holiday lights strung through the canopy can provide gentle warming.
3. Anti-transpirant Sprays: Products that reduce water loss through leaves can offer minimal protection from brief freezes.
4. Container Management: For container specimens, grouping pots together in sheltered locations increases ambient humidity and reduces temperature fluctuations.

Final Summary

Chamaedorea adscendens, the Velvet Palm, is a small, understory palm native to limestone forest regions of Guatemala and Belize. Its most distinctive features are its velvety, leathery grey-blue-green leaves, making it one of the most attractive species in the Chamaedorea genus despite its relative rarity in cultivation.

This palm thrives in warm, humid conditions with filtered light, well-draining soil, and consistent moisture. It grows slowly to a maximum height of about 2.5 meters, making it suitable for both indoor cultivation and as an understory accent in tropical and subtropical landscapes. Propagation is primarily through seeds, which require specific conditions and patience due to their slow germination timeframe.

While not as cold-hardy as some other Chamaedorea species, C. adscendens can be successfully grown in protected locations in USDA zones 10-11, and potentially in warm zone 9b locations with winter protection. Its elegant appearance, manageable size, and relatively low maintenance requirements make it a valuable addition to palm collections and shaded landscape areas, though conservation concerns should be noted as wild populations are considered vulnerable due to habitat loss and fragmentation.