Description:
Fennel (Foeniculum vulgare) is an erect perennial herb, four to ten
feet tall, with finely dissected, almost feathery leaves and characterized
by a strong anise scent originating from stems and leaves. The flowers
are yellow and small (one-quarter inch across), and are clustered
in large, rounded, umbrella-like groups (compound umbels), roughly
four inches across, that are conspicuous from April through July.
During the growing season plants usually include a mixture of living
and dead hollow stems (canes). Branches arise from the stems at conspicuously
jointed nodes, and leaves arise both from the root crown and from
the stems. Leaves sheath the stems where they meet. Seeds of wild
fennel look like the fennel seed commonly used as a flavoring in
foods: they are oblong, dorsally compressed, and ribbed.
Fennel will invade areas where the soil has been disturbed and
can exclude or prevent reestablishment of native plant species.
It can drastically alter the composition and structure of many
plant communities, including grasslands, coastal scrub, riparian,
and wetland communities.
- Mechanical: Manual
methods are most effective when infestations are light and
locally restricted (Dash and Gliessman 1994). Digging out individual
plants by hand is preferred to plowing or bulldozing because
it minimizes soil disturbance, but it is labor-intensive.
- Biological: No
biological controls agents for fennel are known.
- Herbicide:
Brenton and Klinger (1994 and in review) found that 95 to 100
percent kill was achieved when amine and ester formulations
of triclopyr (Garlon ® and Garlon®,
respectively) were applied to fennel in early spring at rates
of 6 lbs/100 gallons water (1 lb active ingredient/acre)
on Santa Cruz Island.
For More Information:
Detailed information about common
fennel is available at the Washington
State Noxious Weed Control Board Web Site. |
