Weeds of National Significance

WILLOW IDENTIFICATION

Part 3 – male or female

Supported by the State Government of Victoria.

Only males produce pollenOnly males produce pollen

Pollen primarily dispersed by bees or windPollen primarily dispersed by bees or wind

Only males produce pollenOnly males produce pollen

Several stamens per flower each Several stamens per flower each with a with a bright yellow pollen sackbright yellow pollen sack

Only males produce pollenOnly males produce pollen

Only males produce pollenOnly males produce pollen

Females have Females have bulbous greenbulbous green ovaries ovaries

Each with a single stigmaEach with a single stigma

Females have Females have bulbous greenbulbous green ovaries ovaries

Females have Females have bulbous green *bulbous green * ovaries ovaries

* May look * May look yellowyellow if water/heat stressed if water/heat stressed* Turns * Turns brownbrown when sheds seed and dries out when sheds seed and dries out

Females produce seedFemales produce seed

What is happening here?

Females shed lots of seed!Females shed lots of seed!

Pollinations is likely to occur and seed produced if Pollinations is likely to occur and seed produced if you have:you have:• male and female flowers (within approx. 2km)male and female flowers (within approx. 2km)• same subgenus (trees or shrubs) same subgenus (trees or shrubs) • flowering times overlap flowering times overlap

(varies among taxa from Aug to Nov)(varies among taxa from Aug to Nov)

Golden Weeping Willow (Salix x sepulcralis var. chrysocoma)

New Zealand hybrid willow (Salix alba x S. matsudana)

Female flowersMale flowers

What is strange about these pictures?

Female flowers Male flowers

Seed viability?

• One willow can produce thousands of seed each spring

• Must germinate within 1-2 weeks to survive• Can germinate within just 6-8 hours!• Biggest known culprits –

Salix nigra (black willow)

Salix cinerea (grey sallow)