Type: Reference Wiki / Lookup Database Use case: Quickly compare root aggression, depth, spread, and safe planting distances across common landscape and screening trees before choosing what to plant near a house, pool, driveway, or pipe run.
| Tree / Cultivar | Root Aggression | Typical Root Depth | Typical Root Spread | Min. Distance from Foundation | Min. Distance from Pipes | Mature Height | Notes |
|---|---|---|---|---|---|---|---|
| Teddy Bear Magnolia | Low | 45–90 cm | 3.5–5 m (1.5–2× canopy) | 3–4 m | 2–3 m | 4–6 m | Compact cultivar of M. grandiflora; fleshy, non-woody young roots |
| Little Gem Magnolia | Low | 45–90 cm | Slightly wider than Teddy Bear | 3–4 m | 2–3 m | 5–8 m | Same root profile as Teddy Bear, taller mature form |
| Southern Magnolia (standard) | Low–Moderate | 60–90 cm | Wide, matches large canopy | 5–6 m | 3–4 m | 12–20 m | Full-size parent species of the compact cultivars above |
| Liquid Amber (Sweetgum) | High | 60–100+ cm | Very wide, aggressive surface roots | 8–10 m | 6–8 m | 15–25 m | Well-documented for pavement and slab lifting |
| Willow | Very High | Shallow, wide | Seeks water aggressively | 15–20 m | 15 m+ | 10–15 m | One of the most pipe-invasive species commonly planted |
| Poplar | Very High | Shallow, extensive suckering | Extremely wide | 15–20 m | 15 m+ | 15–30 m | Suckers can emerge metres from the trunk |
| Ficus (Fig Trees) | Very High | Shallow to deep, very strong | Very wide, strong buttressing | 15 m+ | 10 m+ | 10–30 m | Frequently restricted/removed near infrastructure in AU councils |
| Gum Tree (Eucalyptus, generic) | High | Variable, often shallow & wide | Very wide | 10–15 m | 8–10 m | 10–40+ m | Risk varies heavily by species; drop-limb risk also relevant |
| Jacaranda | Moderate | Moderate depth, wide spread | Wide | 6–8 m | 4–5 m | 10–15 m | Surface roots common on lawns |
| Crepe Myrtle | Low | Shallow–moderate | Moderate | 2–3 m | 1.5–2 m | 3–8 m | Popular low-risk flowering option |
| Photinia Fraseri Robusta | Low | Moderate | Moderate, hedge-forming | 1.5–2 m (hedge spacing) | 1.5–2 m | 3–5 m | Common hedge alternative, faster growing than magnolias |
| Pittosporum Silver Sheen | Low | Moderate | Moderate, fibrous | 2–3 m | 1.5–2 m | 4–8 m | Popular evergreen screening comparator |
| Lilly Pilly (Broad Leaf) | Low–Moderate | Moderate | Moderate–wide | 2–3 m | 2 m | 3–10 m | Root risk rises with larger cultivars |
| Blueberry Ash | Low | Moderate | Moderate | 3–4 m | 2–3 m | 5–10 m | Native, generally garden-safe |
| Queensland Firewheel Tree | Low–Moderate | Moderate–deep | Moderate | 4–5 m | 3 m | 8–15 m | Larger native specimen tree |
| Michelia Figo (Port Wine Magnolia) | Low | Shallow–moderate | Compact | 2 m | 1.5–2 m | 2–3 m | Smaller magnolia relative, shrub-like |
| Dwarf Forest Pansy | Low | Shallow | Compact | 2 m | 1.5 m | 3–5 m | Ornamental, low structural risk |
| Silver Birch | Moderate | Shallow, fibrous, water-seeking | Moderate–wide | 5–6 m | 4–5 m | 10–15 m | Roots seek moisture; watch near pools |
| Oak (English/Common) | Moderate–High | Deep taproot + wide laterals | Very wide at maturity | 10 m+ | 6–8 m | 20–25 m | Deep-rooted but old trees can still lift paving |
| Bamboo (running varieties) | Very High | Shallow, rhizomatic | Unlimited without barrier | Physical barrier required | Physical barrier required | 3–15 m | Not a "root" risk in the traditional sense — spreads via rhizomes; needs root barrier regardless of distance |
| Crepe Jasmine / small shrubs (generic low-risk shrub baseline) | Very Low | Shallow | Narrow | 1 m | 1 m | 1–3 m | Baseline reference for negligible-risk plantings |
| Structure Type | Recommended Minimum Distance |
|---|---|
| House foundation | 3–4 m |
| Underground pipes | 2–3 m |
| Driveways and paving | 2–3 m |
| Pools or retaining walls | 3–4 m |
| Neighbouring fences | 1.5–2 m |
| Hedge spacing (centre-to-centre) | 1.5–2 m |
Q: My tree isn't in the master table — how do I estimate its risk? A: Cross-reference mature height and known growth habit: fast-growing, water-seeking species (willows, poplars, figs) are almost always high-risk; slow-growing, compact cultivars (magnolia dwarf forms, photinia, pittosporum) are almost always low-risk.
Q: Is a wide root spread automatically a problem? A: No. Spread describes area covered, not aggression. A tree can spread 5 m and still be classified "Low" risk if its roots are fine, fleshy, and non-seeking (e.g., Teddy Bear Magnolia).
Q: My soil is heavy clay — do I need to increase all these distances? A: Add 20–30% to the minimum distance figures above as a safety margin in compacted clay, since roots are pushed shallower and more laterally in poor-draining soil.
Q: Do these distances apply to established mature trees I'm assessing on an existing property? A: These are planting-time guidelines. For existing trees already closer than the minimum, monitor for paving lift, foundation cracking, or slow drain blockages rather than assuming a fixed rule applies retroactively.