Xanthorrhoea johnsonii

Common name(s): Yacca, Grass Tree, Johnson's Grass Tree, Queensland Grass Tree, Northern Grass Tree

Family: Xanthorrhoeaceae (Asphodelaceae)

Plant

Taken by Unknown Photographer

Flowers

Taken by Unknown Photographer

Seeds Scale 0.5mm

Taken by Unknown Photographer

Plant

Taken by Ken Harrington on 11th August, 2025 at Morayfields, Queensland

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Plant Properties

Origin(s)

Australia

NSW: NS, NT, NC, NP, CC
NT: CS
QLD: CO, KN, KS, LE, PC, BN, WB, DD, MO

Plant Type

Herb-Perennial

Climate Range(s) - Habitat

Temperate Warm, Mediterranean, Tropical-Sub, Tropical

Temperate Warm,

Mediterranean,

Tropical-Sub,

Tropical

Aspect Range(s)

Sun - Full, Shade - Dappled

Sun - Full,

Shade - Dappled

Habitat Range(s)

Garden, Forest - Grassy, Heath, Landscape, Open Woodlands, Sclerophyll Forest - Wet

Garden,

Forest - Grassy,

Heath,

Landscape,

Open Woodlands,

Sclerophyll Forest - Wet

Habitat Zone(s)

Exposed Stony embankments, Gullies / Valley's / Canyon's, Moist areas, Moist Slopes, Open areas, Ridges, Rock crevices, Rocky, Sandy Moist, Understory, Well drained

Exposed Stony embankments,

Gullies / Valley's / Canyon's,

Moist areas,

Moist Slopes,

Open areas,

Ridges,

Rock crevices,

Rocky,

Sandy Moist,

Understory,

Well drained

Mature Height

5-6m

Plant Shape

Standard Crown - Dense

Growth Rate

Slow

Life Span

300-400yrs

Leaf Properties

Colour (front)

Green

Colour (back)

Green

Shape(s)

Linear

Aroma

None

Texture (front)

Glabrous

Texture (back)

Glabrous

Leaf Length(s)

500-600mm

Leaf Width(s)

20-25mm

Margin

Entire

Cross Section(s)

Quadrate

Rhomboid

Quadrate,

Rhomboid

Venation(s)

Parallel

Arrangement

Dense Crown

Apice(s)

Acute Narrowly

Base(s)

Truncate

Bark / Stem / Culm Properties

Colour(s) Upper

Black , Brown

Black,

Brown

Texture(s) Upper

Bristly / Hispid

Rough / Scabrous

Bristly / Hispid,

Rough / Scabrous

Trunk / Stem Construction(s)

Pith Continuous

Trunk / Stem / Culm Cross Section

Terete

Trunk / Stem / Culm Length

3.5-4m

Flower Properties

Gender: Bisexual

Time(s)

Autumn Late - Summer Early

Flower Colour(s)

Cream

Flower Size(s) Width

10-15mm

Petal Shape(s)

Linear

Aroma(s)

Sweet-slight

Arrangement(s)

Spike

Arrangement Size(s)

1-2m

Pollinator(s)

Bees, Insects, Birds

Bees,

Insects,

Birds

Male and Female Flowers, Borne

On Same Plant

Petal Number

Fruit Properties

Type

Coccum

Shape(s)

Deltoid

Outer Colour(s)

Brown

Outer Texture

Rough / Scabrous

Length

10-15mm

Seed Properties

Type

Samara

Colour(s)

Black

Shape(s)

Cuneate

Texture(s)

Papery

Smooth

Papery,

Smooth

Seed Number

Root Properties

Type

Fibrous

Deep

Texture

Rough / Scabrous

Fleshy , Stiff

Fleshy,

Stiff

Colour(s)

Brown Dark, Brown-black

Brown Dark,

Brown-black

Soil Properties

Type(s)

Clay-loam, Loam, Sandy-loam, Sand

Clay-loam,

Loam,

Sandy-loam,

Sand

pH Range(s)

Acid, Slightly Acid, Neutral

Acid,

Slightly Acid,

Neutral

Condition(s)

Moist

Poor , Deep , Shallow , Well Drained

Poor,

Deep,

Shallow,

Well Drained

Salinities

None

Other Properties / Uses

Bird Attraction

Nectar

Butterfly Attraction

Moderate

Frog Habitat

None

Coastal

2nd Line

Edible(s)

Nectar

Fire Regeneration(s)

Seed, Regrowth

Seed,

Regrowth

Fire Retarding

None

Drought Tolerance

Moderate

Frost Tolerance

Moderate

Snow Tolerance

None

Smog Tolerant

Moderate

Indigenous Use(s)

Flower, Sap

Flower,

Sap

Landscape Use

Good

Street Use

None

Commercial Use(s)

None

Pests/Diseases

Phytophthora cinnamomi

Special Purpose(s)

Foliage, Foliage-interesting, Interesting Buds or Fruit, Interesting Trunk, Phytophthora Susceptible, Shade Tolerant, Shady Dry, Shady Moist, Specimen, Sunny Moist

Foliage,

Foliage-interesting,

Interesting Buds or Fruit,

Interesting Trunk,

Phytophthora Susceptible,

Shade Tolerant,

Shady Dry,

Shady Moist,

Specimen,

Sunny Moist

Propagation

Smoke Stratified Seed

General Notes

An iconic specimen or feature plant for gardens and landscaping with trunks up to 3 metres tall and sometimes branched. Very slow growing, about 88mm per year, it takes several years before it flowers and flowers prolifically after a bush fire. Some are estimated to be 350-450 years old.

A food source for nectar eating birds, bee's and butterflies.

Aborigines soaked the flowering spikes in water to produce a sweet drink. The soft, white leaf bases were eaten, while the flower spike resin was used as an adhesive in the manufacture of tools.

Propagation Notes

Smoke Stratified Seed

Material Preparation

Cut off the spike as the capsules on the spike are just starting to open and the seed has turned black inside. Cut the spike into lengths and place in a large sack. Dry the spike fully in a warm place and the seed should full out of the capsule. Clean. Store in a cool dark place until sowing time.

Propagating Mix

3 parts Premium Seed Raising Mix + 1 part washed sand

Treatment

Sow seed, cover lightly with mix, fine gravel, water in with smoked water, place outside.

Viable seeds/gram:- 38

Germination time:- 26 – 52 weeks

Pricking out:- 26 – 45 weeks into tubes after germination

Tube Mix:- 3 parts Premium Seed Raising Mix + 1 part washed sand

Notes

Add a small amount of Puffball Fungus spore to encourage soil mychorriza to aid the germination and root growth in both the seed raising mix and the potting mix.

Tube stock can be 2-3 years old before it is large enough to plant out.

For direct seeding, sow from mid-winter in low rainfall areas and spring in higher rainfall areas.