Guide to Native and Invasive Plants Storke Ranch Vernal ... - Cram

Invasive Species
Invasive species are introduced species
that out-compete native species for space
and resources. Invasives crowd out native
plants and in some cases alter conditions
in their immediate vicinity, making the
habitat less suitable or wholly unsuitable
for native plants and habitat dependent
wildlife. Many invasives establish
themselves and thrive under disturbed
conditions. In this guide the terms
invasive species, invasives, and weeds will
be used interchangeably.
General weeding guidance/timing
In general, because of their harsh hydrologic regime, vernal pools are largely resistant to weed invasion. The
intensity of invasion pressure increases from the deepest part of the vernal pool to the shallowest part, with
upland areas lacking the resistance to invasion that is provided within the flooded basin. Repeated dry years,
during which the duration of flooding is limited, will result in increased invasion pressure within vernal pools.
Vernal pools should be checked at least annually for invasive species. As vernal pools dry in the spring, plants
flower in concentric rings around the pool. The best time for weed control is in the spring as the pools begin
to dry. Weed around the pool while there is still some moisture left in the soil but before the plants set seed.
As the pool dries, check around the edges of the pool for weeds such as rabbitfoot grass, burclover, Italian
rye grass, hyssop loosestrife, curly dock, English plantain, ripgut brome, common brassbuttons, cut-leaved
geranium, filaree, and vetch. If soil moisture levels are still high, these weeds can generally be removed by
hand pulling or with the help of a small trowel.
Care should be taken to prevent damage to vernal pools during weeding activities. In general, select the weed
control method that creates the least disturbance. Limit the trampling of native plants, and avoid compacting
the soil as much as possible during weed control activities.
One of the best methods of controlling weeds is to prevent them from being introduced and spread in the first
place. To prevent introduction and spread of weeds, limit disturbance, control weeds in surrounding areas,
and educate neighbors and the public about weeds and how they are spread. Remove seeds from clothing and
equipment before entering vernal pool areas.
Some general weeding techniques are outlined below. The Invasives section of this guide provides more
detailed information about some of the common weeds in and around vernal pools along with common control
methods. Refer to that section for specifics on individual plants.