Alien
Invasion, Part 6:
Fennel
Fennel,
sometimes called sweet fennel (Foeniculum
vulgare), is a member of the plant family Umbelliferae or Apiaceae
(carrots). Fennel is a perennial plant
that is native to southern
Fennel (Foeniculum vulgare)
Photo courtesy of John M.
Randall/ The Nature Conservancy
Fennel
starts sprouting as a cluster of very finely divided, hair-like greenery in the
spring. The leaves are called pinnately compound. As stalks develop, the plants eventually
become quite tall, 3-6 feet in height.
Full height may take multiple seasons of resprouting. The plant develops a large taproot from which
it resprouts. There is a thin, waxy
coating on the stems and leaves, and sheathing at the base of each branch on a
stalk. Eventually, compound flower heads
develop, with numerous rays ending in wide-petalled, yellow blossoms. The fruit is ovate and ribbed. The seeds are dark and flat-faced. Once a plant is well established, new stalks
with flowers are produced every year.
Fennel
can be identified by its sweet, anise smell.
Fennel leaves and seeds have been used for cooking and sausage making
and in liqueurs. The oil has been used
in soap, medicine and perfume. The plant
was introduced and cultivated in the
The
plant can propagate from root division or from seeds. Root division can be introduced by flooding
or human activity such as cultivation. Seeds
can be dispersed by water as well as human and animal activity. Once established, a stand of fennel is
difficult to eradicate. Deep cultivation
is required to remove the well-established taproot. Because of its strong smell, generally
animals do not graze it.
Fennel
has established stands in the southwest and northeast corners of the
Herbicides
used on fennel include 2,4-D diluted to one part in 400 parts water. Application should be prior to
flowering. A combination of picloram and
2,4,5-T has been applied at flowering as well.
In
No
biological controls (insects, etc.) are available at this time.