Forster's Clematis
Clematis forsteri
Clematis forsteri , commonly known as Forster's Clematis or Pikiarero, is a beautiful native New Zealand climber renowned for its masses of starry white flowers in spring. This vigorous and attractive vine adds elegance and fragrance to gardens, making it a popular choice for covering fences, pergolas, or climbing through shrubs and trees. It is a delightful spectacle when in full bloom.
Plant Description
Clematis forsteri is a scrambling or climbing woody liane that can reach several meters in length. It attaches itself to supporting structures by means of its twining leaf stalks (petioles). The leaves are trifoliate (composed of three leaflets), with each leaflet being ovate to lanceolate, dark green, and often toothed. In spring (typically September to November), the plant becomes covered in a profusion of small (2-4 cm diameter), starry, pure white flowers, often with a delicate fragrance. These flowers are followed by attractive, feathery seed heads that persist into summer, adding further ornamental interest.
Quick Facts
| Family | Ranunculaceae (Buttercup family) |
|---|---|
| Light | Full sun to partial shade |
| Soil | Moist, fertile, well-drained |
| Water | Moderate |
| Water Needs | Moderate |
| Frost Tolerance | Hardy |
| Salt Tolerance | Moderate |
| Growth Rate | Moderate |
| Scientific Name | Clematis forsteri |
| Height | Climbing up to 5 m |
| Spread | Spreading up to 2-3 m |
| Lifespan | Perennial |
Climate Best Suited to
Clematis forsteri is widespread throughout New Zealand, demonstrating remarkable adaptability to various climate zones. From coastal to montane forests, this vigorous climber tolerates temperatures from -10°C to 30°C. It performs best in areas with moderate rainfall (800-1500mm annually) and some humidity, though established plants show good drought tolerance.
Regional Suitability
| City | Climate Suitability |
|---|---|
| Whangārei | Ideal |
| Auckland | Ideal |
| Hamilton | Ideal |
| Tauranga | Ideal |
| Rotorua | Ideal |
| Gisborne | Ideal |
| New Plymouth | Ideal |
| Napier | Suitable |
| Whanganui | Ideal |
| Palmerston North | Ideal |
| Wellington | Ideal |
| Nelson | Ideal |
| Christchurch | Ideal |
| Dunedin | Suitable |
| Invercargill | Suitable |
Habitat
Natural Distribution
Clematis forsteri is typically found in lowland and coastal forests, forest margins, and shrubland throughout New Zealand. It often grows in damp, fertile soils, scrambling over other vegetation, rocky banks, or along stream edges. It is a pioneer species that can colonize disturbed areas, contributing to natural regeneration.
Conservation Status
Current Threats and Protection
Clematis forsteri is classified as "Not Threatened" under the New Zealand Threat Classification System. It is a relatively widespread and common species in suitable habitats. While generally secure, local populations can be affected by habitat modification and competition from invasive plant species. Conservation efforts focus on protecting and managing its forest and shrubland habitats.
How to Grow
Cultivation Requirements
Clematis forsteri is a robust and relatively easy-to-grow climber. It thrives in full sun to partial shade, with its roots kept cool and moist. Plant in moist, fertile, and well-drained soil rich in organic matter. Provide a supporting structure such as a trellis, fence, or allow it to scramble through a sturdy shrub or small tree. Water regularly, especially during dry periods and during its active growth and flowering seasons. Fertilize lightly in spring with a balanced native plant fertilizer.
Planting Guide
Best Planting Practices
Plant Clematis forsteri in spring or autumn. Choose a site that receives sun for its foliage but offers some shade to keep its roots cool. Dig a planting hole twice the width of the root ball and the same depth. Incorporate plenty of organic matter into the soil. Position the plant near its support structure, gently firm the soil, and water thoroughly. Apply a thick layer of mulch to keep the root zone cool and moist.
Ecological Role
Environmental Benefits
Clematis forsteri plays an important ecological role as a native climber. Its abundant spring flowers provide nectar and pollen for a variety of native insects, contributing to the local pollinator community. Its dense growth provides habitat and shelter for small birds and invertebrates, and its scrambling habit helps to bind soil on banks and slopes.
Uses
Traditional and Modern Applications
Clematis forsteri is highly valued as an ornamental plant in gardens. It is excellent for covering unsightly fences or walls, creating a beautiful spring display on pergolas, or allowed to ramble naturally through other plants. Its delicate flowers can also be used as cut flowers.
Landscaping Uses
Garden Design Applications
Use Clematis forsteri to add vertical interest, soften hard landscaping features, or create a romantic, cottage-garden feel in native plantings. It is superb for training over arches, arbors, or through the branches of deciduous trees. Its vigorous growth quickly provides coverage and a burst of spring colour.
Seasonal Care
Year-Round Maintenance
Clematis forsteri requires regular watering, especially during dry spells. In late winter or early spring, apply a balanced native plant fertilizer. Pruning is best done after flowering. Keep the root zone mulched to maintain moisture and suppress weeds.
Pruning
Pruning Techniques
Clematis forsteri can be pruned after its main flowering period in late spring or early summer. Light pruning is typically sufficient to maintain shape and control its spread. Remove any dead or damaged stems, and thin out overcrowded growth to improve air circulation. More extensive pruning can be done to rejuvenate older plants or to keep them within bounds.
How to Grow Forster's Clematis
From Seed
Propagation of Clematis forsteri from seed can be a rewarding, though sometimes slow, process. Collect seeds in late summer to early autumn when the distinctive feathery tails are fully mature. Clematis seeds often exhibit dormancy and benefit from a period of cold stratification; mixing them with moist sand or vermiculite and refrigerating for 8-12 weeks before sowing can improve germination rates. Sow seeds onto a well-draining seed-raising mix, lightly covering them. Maintain consistent moisture and cool temperatures (around 10-15°C or 50-60°F). Germination can be erratic, taking several weeks to many months. Once seedlings are robust enough, prick them out into individual pots and grow them on in a sheltered, bright location until ready for planting out.
From Cuttings
Clematis forsteri can be successfully propagated from semi-hardwood cuttings taken in late summer to early autumn. Select healthy, non-flowering stems from the current season's growth, ensuring they are firm but still flexible. Cuttings should be about 10-15 cm long with 2-3 leaf nodes. Remove the lower leaves, dip the cut end in a rooting hormone, and insert into a free-draining mix of sand and perlite. Provide high humidity by covering with a plastic bag or placing in a propagation chamber, and maintain warmth (around 18-24°C or 65-75°F) with indirect light. Rooting typically occurs within 6-10 weeks. Once rooted, gradually acclimatize plants to ambient conditions before potting up.
General Cultivation
Forster's Clematis is a vigorous and beautiful native New Zealand climber that thrives in full sun to partial shade, ideally with its roots kept cool and moist. Plant in moist, fertile, and well-drained soil rich in organic matter. Good drainage is crucial to prevent root rot. Provide a strong supporting structure, such as a trellis, pergola, fence, or allow it to scramble through sturdy shrubs or small trees. Water regularly, especially during dry periods and during its active growth and flowering seasons. Apply a balanced native plant fertilizer lightly in spring. Pruning is best done after its main flowering period in late spring or early summer to maintain shape, control spread, and encourage new growth for the following season. Remove any dead or damaged stems and thin out overcrowded growth to improve air circulation.
Pests and Diseases
Common Problems and Solutions
Clematis forsteri is generally a robust and healthy plant, relatively free from serious pests and diseases. The most common issues are related to cultural conditions, such as root rot in poorly drained soils or fungal diseases in overly humid, poorly ventilated environments. Slugs and snails may occasionally damage young shoots. Ensure good air circulation and well-drained soil for optimal health.
Cultural Significance
Traditional Uses and Values
Clematis forsteri holds cultural significance as a prominent native New Zealand climber, known to Māori as Pikiarero. Its masses of white flowers symbolize purity and new beginnings, heralding the arrival of spring. While not as extensively used for practical purposes as some other native plants, its beauty and presence in the forest have long been appreciated. It contributes to the rich botanical heritage of Aotearoa.
Bonus Tip
Expert Growing Advice
For an impressive spring display, plant Clematis forsteri at the base of a deciduous tree or large shrub, allowing it to scramble up through the branches. The flowers will emerge before the host plant fully leafs out, creating a stunning effect.
