Kahakaha

Basic Information

Common Name: Kahakaha
Scientific Name: Collospermum hastatum
Native Habitat: Native to New Zealand, found in forests and shrublands throughout the North Island and northern South Island, typically growing as an epiphyte on trees but occasionally found on rocks or banks.

History / Discovery / Cultivator

The genus *Collospermum*, to which *Collospermum hastatum* belongs, is a small group of epiphytic or terrestrial plants native to New Zealand and the Pacific Islands. These plants were historically grouped within the genus *Astelia* due to their similar appearance, sharing features like strap-like leaves and a tussock-forming habit. However, later botanical studies revealed distinct differences, particularly in their floral structure and seed characteristics, leading to the separation and establishment of the genus *Collospermum*. The name *Collospermum* derives from Greek words meaning “gluey seed,” referring to the mucilaginous coating found on their seeds, an adaptation believed to aid in adherence to tree bark or other substrates when dispersed.

*Collospermum hastatum* itself is one of the most widespread and familiar members of the genus in New Zealand. As an integral part of the native forest ecosystem, it would have been known to Maori for centuries. While specific extensive uses of *Collospermum hastatum* by Maori are not as widely documented as those for some other native plants (like the fibrous properties of *Phormium* or medicinal uses of others), these epiphytic clumps played a role in the forest’s biodiversity. The dense root masses and accumulated detritus within the large tussocks of *Collospermum* and *Astelia* species create microhabitats supporting a variety of invertebrates, fungi, and even providing rooting sites for other epiphytes, ferns, and seedlings. They act as natural reservoirs, collecting rainwater and organic matter high up in the forest canopy, contributing to the nutrient cycling within the epiphyte community.

European botanical exploration of New Zealand began in earnest following Captain James Cook’s voyages in the late 18th century. Botanists like Joseph Banks and Daniel Solander collected and described numerous New Zealand plants, although the formal scientific description and classification of many species continued well into the 19th century and beyond as more specimens were collected and studied. The initial descriptions of plants now placed in *Collospermum* would likely have occurred during this period of intense botanical survey.

The formal scientific description of *Collospermum hastatum* specifically came from T. Kirk, a prominent New Zealand botanist of the late 19th century. Kirk’s extensive work, including his posthumously published “The Students’ Flora of New Zealand and the Outlying Islands” (1899), was foundational to the understanding of the country’s flora. It was through detailed morphological comparisons that botanists later refined the classification, leading to the genus *Collospermum* being formally recognized and species like *C. hastatum* being placed within it, distinct from *Astelia*. The specific epithet “hastatum” means “spear-shaped,” likely referring to the shape of the leaves or a part of the flower structure, though the strap-like leaves are more commonly described as linear or arching.

In terms of cultivation, *Collospermum hastatum* is primarily appreciated within New Zealand’s native plant gardening community and increasingly by international enthusiasts interested in epiphytes and unusual houseplants. It is not typically associated with a single specific cultivator who ‘popularized’ it globally, but rather its gradual introduction into horticulture reflects a growing appreciation for native New Zealand flora and epiphytic plants. Its striking architectural form, tolerance of varying light conditions (compared to some sun-loving epiphytes), and relatively robust nature have made it a desirable plant for suitable garden climates or as an indoor/greenhouse subject where humidity and light can be controlled. Cultivators focus on replicating its native growing conditions: providing an airy, well-draining substrate (if not mounted), consistent moisture without waterlogging, and protection from frost. Its slow growth rate means that mature, established specimens are particularly valued. Its history is less about directed breeding or selection and more about its natural role in its ecosystem and its subsequent recognition and adaptation for cultivation.

Plant Care Summary

Botanical Insights

Adaptations

*Collospermum hastatum* exhibits several key adaptations that enable it to thrive as an epiphyte. Perhaps the most notable is its ability to form a dense, upright tussock with tightly overlapping leaf bases. This structure acts as a natural “tank” or reservoir, efficiently trapping rainwater and falling organic debris such as leaves, bark, and insect remains. Roots grow into this accumulated material, which provides moisture, nutrients, and anchorage high up in the canopy. This allows the plant to access resources without needing contact with the ground. Its sturdy, somewhat leathery leaves also help reduce water loss through transpiration, an important feature for a plant not directly rooted in soil. The plant’s root system is adapted for clinging to rough bark surfaces, providing stability against wind and gravity.

Propagation Methods

Propagation of *Collospermum hastatum* is typically achieved through two main methods:
1. **Seed:** *Collospermum* produces berries containing small seeds covered in a sticky, mucilaginous coating. In nature, this coating aids adherence to host trees. For cultivation, seeds can be sown on a sterile, well-draining medium like sphagnum moss or an orchid mix. They require high humidity and warmth to germinate, which can be facilitated in a propagator or covered container. Germination can be slow and variable.
2. **Division:** Larger, mature clumps can sometimes be carefully divided. This is often challenging as the dense root mass is tightly interwoven. Division should be done cautiously, ensuring each section has a sufficient root system and several healthy leaves. Damaged roots are susceptible to rot, so it’s vital to use clean tools and plant the divisions in a well-draining medium, providing extra humidity during the recovery phase. Division is often less successful than seed propagation for this genus.

Toxicology

*Collospermum hastatum* is generally considered non-toxic to both humans and common household pets like cats and dogs. It belongs to the plant family Asteliaceae. Unlike families known for significant toxins (such as Araceae with their calcium oxalate crystals), the Asteliaceae family is not typically associated with causing severe poisoning upon ingestion. While consuming any plant material can potentially lead to mild digestive upset in sensitive individuals or pets, *Collospermum hastatum* does not contain known harmful compounds that would cause serious toxic reactions or require medical attention.

Common Problems

Pests:

• Scale insects (often found on leaf undersides or bases)
• Mealybugs (small white, cottony insects, particularly in leaf axils)
• Spider mites (more common in dry, low-humidity conditions, causing stippling on leaves)

Diseases:

• Root rot (caused by overwatering or poorly draining substrate)
• Fungal leaf spots (can occur in conditions of high humidity and poor air circulation)

Other:

• Browning leaf tips (most often caused by low humidity or inconsistent watering)
• Leaf yellowing (can indicate overwatering, nutrient deficiency, or sometimes low light)
• Leggy growth (typically a sign of insufficient light, especially indoors)

Rarity & Value

Rarity:

In its native New Zealand habitat, *Collospermum hastatum* is a relatively common plant in suitable forest environments. It is not considered rare or endangered in the wild. However, in cultivation outside of New Zealand, it is less commonly encountered than more widely distributed houseplants. Its rarity in the international horticultural trade stems more from limited availability and slower growth rate compared to highly commercialized species, rather than inherent biological rarity or protection status. Specific large, mature, or well-established specimens mounted on cork bark or grown into impressive clumps can be harder to find.

Value:

The market value of *Collospermum hastatum* is typically influenced by its size and maturity. Smaller, younger plants are moderately priced. Larger, well-developed clumps or specimen-sized plants, especially those that have been cultivated for many years to achieve significant size and presence, command a higher value. Factors like the plant’s overall health, fullness, and presentation (e.g., if it is attractively mounted) also affect its price. While it doesn’t usually reach the high price points seen for trendy rare aroids or variegated plants, a substantial, mature Kahakaha is valued for its architectural beauty, relative hardiness (when cultural needs are met), and representation of New Zealand’s unique flora. The current demand from collectors interested in epiphytes and unusual architectural plants can also play a role in its market value.