What to Grow, Where, and Why
Clay soils can be challenging due to their dense structure, poor drainage, and tendency to compact. However, many New Zealand native plants are well adapted to these conditions and can help improve soil structure, prevent erosion, and create thriving gardens or restored habitats.
What Makes Clay Soils Unique
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Soil Characteristics: Heavy, fine-textured soils that hold moisture but can become waterlogged and compacted. Slow to warm in spring.
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Drainage: Poor natural drainage leading to seasonal waterlogging or surface pooling.
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Nutrient Availability: Often fertile but nutrients may be less accessible due to soil chemistry and aeration.
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Challenges: Risk of root rot if plants are not tolerant of wet feet; difficult for plants that need fast drainage.
What to Plant by Site Type in Clay Soils
Site Type |
Best Plant Choices |
Why These Work |
Wet flats & seasonal wetlands |
Phormium tenax (Harakeke), Carex secta, Machaerina rubiginosa, Juncus edgariae, Baumea articulata |
Adapted to tolerate prolonged wet conditions and fluctuating water tables. |
Poorly drained slopes & gullies |
Griselinia littoralis, Fuchsia excorticata, Pseudopanax crassifolius, Coprosma robusta |
Thrive in moist, shaded areas and improve soil structure with their root systems. |
Dryer clay soils with better drainage |
Kunzea ericoides (Kānuka), Leptospermum scoparium (Mānuka), Ozothamnus leptophyllus (Tauhinu), Coriaria arborea |
Tolerant of heavy soils when well-drained; pioneer species that prepare soil for later colonists. |
Urban clay garden soils |
Melicytus ramiflorus (Mahoe), Coprosma robusta, Pittosporum eugenioides |
Hardy natives that adapt well to compacted urban soils and provide good shelter and greenery. |
Signature Clay Soil Native Plants
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Phormium tenax (Harakeke/Flax) – Thrives in wet soils, excellent for stabilising edges and wet patches.
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Carex secta (Makura) – Tall sedge for swampy, waterlogged sites.
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Griselinia littoralis (Kapuka) – Hardy shrub/tree for moist gullies and shelterbelts.
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Fuchsia excorticata (Tree fuchsia) – Shade-loving native that tolerates moist, clay soils.
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Kunzea ericoides (Kānuka) – Versatile pioneer for regenerating clay sites.
Planting Tips for Clay Soils
Tip |
Advice |
Site preparation |
Improve drainage by creating raised beds or mounds; avoid compaction by minimising walking on wet soil. |
Planting time |
Early spring or autumn to allow roots to establish before wet winter or dry summer conditions. |
Mulching |
Use organic mulch to improve soil structure and retain moisture without waterlogging. |
Root protection |
Select plants with good tolerance for wet feet to prevent root rot. |
Watering |
Generally, avoid additional watering; monitor during dry spells if soil dries out completely. |
Why Choose Natives for Clay Soil?
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Adapted to local conditions, providing resilience in heavy soils
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Improve soil structure over time with fibrous root systems
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Support native wildlife with shelter and food sources
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Reduce maintenance and watering needs once established
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Restore natural ecosystems often dominated by wetlands or riparian zones