Key identifying traits
- Flowers are white, pink
or purple resembling an old-fashioned English policeman's helmet
- Plants grow to 10’ tall
- Stems are hollow with a
purple or reddish tinge
- Leaves are oblong to
egg-shaped; edges serrated
- The fruit is a five
chambered capsule capable of producing 800 seeds
Biology and ecology
- An annual plant
reproducing from seed
- It is often sold as an
ornamental
- This plant is a native
to India and the western Himalayas
- It has a very shallow
root system and requires a high soil moisture to grow
- When touched, the mature
seed pods split and eject seeds up to 20 feet
Control
Prevention –
Learn to identify plants; do not purchase plants that have invasive
tendencies; start monitoring early in the season; do not allow
plants to produce seed
Biological –
No known biological control in our area
Cultural –
Planting a competitive grass or other cover crop can help keep weed
seeds from germinating
Mechanical –
Hand pulling is very effective due to the shallow roots; sheep and
cattle are used to graze the plants in Britain; mowed or cut plants
may resprout
Chemical – Herbicides with 2,4-D
and triclopyr have been said to be effective as well as glyphosate;
the
PNW Weed Management handbook does not have specific chemical
recommendations for policeman’s helmet at this time
|
All photos courtesy WA State Noxious
Weed Control Board |
