Problem Plants in Your California Garden
Some plants that have been introduced into California
grow a little too well. They have escaped gardens and spread into natural
areas, choking out native vegetation and destroying wildlife habitat. Lots
of manual labor and herbicides are used to remove these pests from the
wild. Unfortunately they are continuously reintroduced by unwitting
gardeners planting them in their gardens. As these plants have come from
other areas of the world, they are without their normal biological
controls; that is the herbivores that would normally eat them and
insects, birds and small animals that would eat their seeds, lowering
their germination rate. Here are a few plants that are exceptionally aggressive
and should be avoided.
Periwinkle (Vinca Major)
This fast-growing ground cover spreads rapidly and is very difficult to
eradicate. Every node can grow roots and usually does so when it makes
contact with soil. It blankets large areas smothering native
vegetation. Try some friendlier choices instead. For an evergreen look
and blue flowers, plant Carmel Mountain Lilac (Ceanothus 'Yankee Point').
For a tough no-nonsense ground cover, try Hayes iva (Iva hayesiana).
This aggressive grass makes large, dense clumps and its seeds can
spread for miles. Removing it can be painful and very difficult. Its
sharp, serrated leaves can easily slice open exposed flesh, and its
strong roots make it almost impossible to remove without heavy
machinery. A friendlier choice is Giant Rye (Elymus condensatus) or
Bear Grass (Nolina bigelovii).
Green Fountain Grass
Another invasive grass, this one is also spreading rapidly into wild
lands and choking out native vegetation. Because of its dry kindling-
like form, it can increase the risk or wildfires. Some friendlier
alternatives are the tidy silver bunch grass (Fetsuca idahoensis) or a
large bunchgrass like deer grass (Muhlenbergia rigens).
Sometimes known as green wattle, golden wattle, or coastal wattle, these aggressive shrubs spread into waterways as well as dry land, forming dense clumps that overrun native vegetation. If a good coastal shrub or screen is what you are looking for, try Pacific Wax Myrtle
(Myrica californica) or California Coffeeberry (Rhamnus californica)
instead. If you want yellow flowers, try Nevin's Barberry (Mahonia nevinii).
This nasty groundcover was planted in many coastal areas for erosion
control. It has since spread out of control, overrunning many very sensitive
regions and killing almost every plant in its path. A few friendlier choices
are the shiny green ground cover, California Wild Strawberry (Fragaria
chiloensis) or a lovely silver ground cover, Watson's Saltbush (Atriplex
watsonii). Both can grow in very close proximity to the ocean and can
grow in beach sand.