Silver tree (witteboom) Leucadendron argenteum
Silver tree (witteboom) (Leucadendron argenteum) is an evergreen perennial tree in the Proteaceae family, native to Cape Peninsula, mainly the slopes of Table Mountain (granite clay). It grows 5–10 m (16–33 ft) tall and 3–5 m (10–16 ft) wide, wants full sun and low water, and is hardy to about -3 °C (27 °F). Space plants about 4 m (13 ft) apart.
Plan Silver tree (witteboom) in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Silver tree (witteboom) at a glance
| Type | Perennial tree, evergreen |
|---|---|
| Family | Proteaceae |
| Mature height | 5–10 m (16–33 ft) |
| Mature spread | 3–5 m (10–16 ft) |
| Spacing | 4 m (13 ft) centre to centre |
| Sun | Full sun, at least 7 h of direct sun a day |
| Water | Low; drought tolerance moderate, waterlogging tolerance none |
| Soil pH | 4.5–6.5 |
| Cold hardiness | About -3 °C (27 °F) once established (roughly USDA zone 9) |
| Heat stress | Likely above about 35 °C (95 °F) |
| Flowering | from about September for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | High |
| Pollinator value | Low |
| Edible | Not grown as food |
| Native to | Cape Peninsula, mainly the slopes of Table Mountain (granite clay) |
| Common in gardens of | 🇿🇦 South Africa |
Is Silver tree (witteboom) toxic?
- People: not known to be toxic
- Cats: not known to be toxic
- Dogs: not known to be toxic
No toxicity reported in ASPCA or standard poison references.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Silver tree (witteboom)
No well-documented helpful pairing. Group it with plants that like full sun and low water.
See Silver tree (witteboom) in a botanical garden
It grows in these sample gardens, which you can walk through in 3D:
- UC Botanical Garden, Berkeley (2 plants)
- Gardens by the Bay (2 plants)
- Kirstenbosch (6 plants)
Questions about Silver tree (witteboom)
- How far apart should I plant Silver tree (witteboom)?
- About 4 m (13 ft) apart, centre to centre. A mature plant spreads 3–5 m (10–16 ft).
- Does Silver tree (witteboom) need full sun?
- Full sun: at least 7 hours of direct sun a day.
- How much water does Silver tree (witteboom) need?
- Low water. Drought tolerance is moderate and waterlogging tolerance none.
- How cold-hardy is Silver tree (witteboom)?
- It tolerates about -3 °C (27 °F) once established, roughly USDA zone 9.
- When does Silver tree (witteboom) flower?
- From about September for 4–7 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Silver tree (witteboom) poisonous to cats and dogs?
- For cats it is not known to be toxic; for dogs not known to be toxic; for people not known to be toxic. No toxicity reported in ASPCA or standard poison references.
- What grows well with Silver tree (witteboom)?
- There is no well-documented companion pairing for Silver tree (witteboom). Group it with plants that like the same sun (full sun) and water (low).
Sources and evidence
Evidence grade A (A: strong evidence).
- PlantZAfrica, South African National Biodiversity Institute
- Kirstenbosch National Botanical Garden: gardens and collections, South African National Biodiversity Institute (SANBI)
- IUCN Red List of Threatened Species, IUCN
Notes and assumptions
- Fynbos: acid, low-phosphorus, sandy soil; no manure or phosphate fertiliser; needs good air movement and dislikes humid summers.
- Silky silver-haired leaves shimmer in the wind; Endangered (IUCN). Kirstenbosch's Silver Tree Trail runs through wild stands. Wind-pollinated; female trees bear silver cones.
- Short-lived (30–40 years).
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Macadamia Macadamia integrifolia
- King protea Protea cynaroides
- Pincushion protea Leucospermum cordifolium
- Rosemary grevillea Grevillea rosmarinifolia
- Coast banksia Banksia integrifolia
- Waratah Telopea speciosissima
- Oleander-leaf protea Protea neriifolia
- Common sugarbush Protea repens