Astelia forbesii

Basic Information

Common Name: Astelia forbesii
Scientific Name: Astelia forbesii
Native Habitat: Native to the North Island of New Zealand, typically found in lowland forests, often growing terrestrially among leaf litter or epiphytically on trees. It is commonly found in damp, shaded gullies and coastal broadleaf forests.

History / Discovery / Cultivator

The genus Astelia belongs to the Asteliaceae family, which is closely related to the broader Asparagaceae order. Astelia forbesii, like many other species in the genus, is endemic to the islands of New Zealand, reflecting the unique evolutionary history of its flora. While precise records detailing the specific discovery of Astelia forbesii by European botanists can be elusive, the plant was formally described as part of the taxonomic classification efforts that took place throughout the 19th century as botanists explored and documented the biodiversity of New Zealand. It was named in honour of the British botanist and horticulturalist, John Forbes.Prior to European arrival and formal scientific classification, Astelia species held significance for the indigenous Maori people of New Zealand. Various species were used for different purposes. While specific traditional uses for Astelia forbesii itself might not be as well-documented as for larger, more fibrous species like Astelia fragrans (known as ‘kakaha’), which had uses in weaving or cordage, it is plausible that the plants were observed for their presence as indicators of certain forest types or simply appreciated for their aesthetic qualities within the native landscape. The shiny, often metallic-looking foliage characteristic of many Astelias, including A. forbesii, is a striking feature of the undergrowth and canopy layers where they occur.Astelia forbesii is one of several Astelia species found in New Zealand’s North Island forests. Its ability to grow both on the ground and as an epiphyte on host trees demonstrates an ecological versatility common within the genus. This adaptation allows it to exploit different niches within the forest ecosystem, from the shaded, humid forest floor to the slightly brighter, yet still protected, environment found on tree trunks and branches.In terms of cultivation, Astelia forbesii has gained some popularity among enthusiasts of New Zealand native plants and those interested in unique foliage. While not as widely grown or commercially available as some other ornamental plants, its striking appearance – typically featuring long, strap-like leaves with a distinctive sheen, often displaying silver, bronze, or greenish-bronze tones on the underside – makes it a desirable addition to gardens, particularly in regions with mild, humid climates similar to its native environment. Cultivation efforts have focused on understanding its specific requirements regarding light, water, and substrate to successfully propagate and grow it outside its natural habitat. It is primarily propagated through division of its rhizomatous clumps, a method that preserves the characteristics of the parent plant. Its introduction into horticulture is part of the broader appreciation and cultivation of New Zealand’s unique native flora, driven by gardeners and nurseries specializing in endemic species. Compared to some showier flowering plants, Astelias, including A. forbesii, are primarily valued for their architectural form and foliage, fitting well into shaded or woodland garden designs.

Plant Care Summary

Category	General Requirement	Notes
Light	Bright Indirect to Shade	Prefers filtered light or shade; direct sun can scorch leaves.
Water	Moderate & Consistent	Keep soil consistently moist but not waterlogged; reduce in winter.
Humidity	High	Thrives in high humidity; regular misting or a pebble tray is beneficial indoors.
Temp. Range	10-25°C (50-77°F)	Protect from frost and extreme heat. Prefers cool, stable temperatures.
Soil Type	Well-draining, Humus-rich	Use a mix suitable for epiphytes or woodland plants; bark, perlite, peat/coir.
Fertilizer	Light (Spring/Summer)	Use a diluted balanced liquid fertilizer every 4-6 weeks during growing season.
Toxicity	Mildly Toxic	Contains calcium oxalate crystals which can cause irritation if ingested.

Botanical Insights

Adaptations

Astelia forbesii exhibits several adaptations suited to its native New Zealand forest habitat. Its thick, leathery leaves, often with a waxy or scaly surface (which contributes to the metallic sheen), help reduce water loss, a useful trait even in humid environments, particularly when growing epiphytically where water supply can be less constant than in soil. The plant grows from a rhizomatous base, forming dense clumps. This rhizomatous growth allows it to spread vegetatively, colonizing suitable areas on the forest floor or along branches. When growing epiphytically, its roots are adapted to cling to bark and absorb moisture and nutrients from rain, debris, and the humid air rather than deep soil. The plant’s overall form, with upright to arching strap-like leaves, is efficient at channeling rainwater towards the center of the clump and down towards the roots. Its tolerance for shade is also a key adaptation for life in the understorey or within the canopy where light is filtered.

Propagation Methods

The most common and reliable method for propagating Astelia forbesii is by division. As the plant matures, it forms multiple growing points (clumps) along its rhizome. These clumps can be carefully separated during repotting, ensuring each division has a healthy section of rhizome and sufficient roots. Division is best performed in the spring as the plant enters its active growth phase. Seed propagation is also possible, but seeds can be slow to germinate and grow, and results may vary depending on the specific provenance and whether the plant was cross-pollinated. Tissue culture is sometimes used for mass propagation in commercial settings but is not feasible for the home grower.

Toxicology

Like many plants in the Asparagaceae family, Astelia forbesii contains insoluble calcium oxalate crystals. These crystals are microscopic, needle-shaped structures present in the plant’s tissues. If parts of the plant are chewed or ingested by humans or pets (such as cats and dogs), the crystals can penetrate the mucous membranes of the mouth, tongue, throat, and esophagus. This mechanical irritation typically causes immediate symptoms such as intense burning, pain, swelling, and irritation of the oral cavity. Drooling, difficulty swallowing, and vomiting may also occur. While the reaction is generally localized and causes discomfort, it is not considered severely poisonous, and symptoms are usually self-limiting. However, it’s always best to keep the plant out of reach of curious pets and children.

Common Problems

Pests:

• Spider Mites (especially in low humidity)
• Scale Insects
• Mealybugs

Diseases:

• Root Rot (caused by overwatering and poor drainage)
• Leaf Spot (often fungal, exacerbated by high humidity and poor air circulation)

Other:

• Leaf Yellowing: Often a sign of overwatering, poor drainage, or sometimes nutrient deficiency. Can also occur with sudden temperature changes.
• Brown Leaf Tips/Edges: Usually indicates low humidity, inconsistent watering, or fluoride/salt buildup in water or soil.
• Lack of Growth: Can be due to insufficient light, low temperatures, root bound conditions, or nutrient deficiency.

Rarity & Value

Rarity:

Astelia forbesii is endemic to a specific region of the North Island of New Zealand. While not necessarily considered critically endangered in its native habitat, its distribution is localized. It is also not one of the most commonly cultivated Astelia species outside of specialist native plant nurseries or collections, which contributes to its relative rarity in the general horticultural market compared to more widely distributed or easily propagated plants. Its rarity is linked to its specific environmental needs and potentially slower growth or less prolific propagation compared to some other ornamental species.

Value:

The market value of Astelia forbesii is typically influenced by several factors. As it’s not a mass-produced plant, its price tends to be higher than common houseplants. Size and maturity play a significant role; larger, well-established clumps are more valuable than young seedlings or small divisions. The condition and health of the plant, including the lustre and coloration of the leaves, are also key factors. For collectors of rare or native New Zealand plants, A. forbesii holds particular appeal, increasing its value in niche markets. Current horticultural trends and demand for unique foliage plants can also temporarily impact its price. Provenance, if from a reputable nursery specializing in native species, can also add to its perceived value.