Re: New potential weed

>The weed potential of ornamental plants is a real problem for all
>gardeners - but particularly those in a Mediterranean climate it seem to
>me.
>
>As a gardener interested in new and different plants one of the risks is
>that I will grow something that turns into a weed - I don't know of any
>fool proof way of dealing with this other than being careful and
>vigilant about the behaviour of new plants and removing potential
>problems - but it is an ongoing tension.
>
>Any other thoughts or ideas about how to manage the problem from a
>gardeners perspective would be appreciated
>

        I can't think of a more appropriate topic for this group than this
one.  In Oakland, California several species come to mind.  The hills of
Oakland, once an Oak Woodland, are now a thicket of various--mostly
Mediterranean-species.  *Acacia melanoxylon* is the most grievous offender
from my experience but various brooms, *Genista* and *Cytisus* included, do
their damage, too.  Most of you know that less than ten years ago we had
one of the most horrific urban fires in US history fueled largely by brooms
and *Eucalyptus*.  {In fairness, the Eucs, if watered in the dry, summer,
season would have acted as a fire retardant, but most were so dry that they
provided a bridge for the fire to span great distances quickly.}  Three
thousand homes burned in one afternoon.
        My appreciation of this problem is especially acute because I work
in a plant nursery.  I remember my first month on the job when I saw a huge
endcap of broom.  I did my best to inform customers of the risks involved
with these weeds but we had no trouble selling out, and buying more, of
course.
        I find it a disheartening act to walk the hills of Berkeley and
Oakland.  Most of the native vegetation is gone or going.  Only the great
longevity of the oaks (*Quercus lobata* and *Quercus agrifolia*, primarily)
keeps a noticeable endemic presence.
        There is even another aspect to this question, i.e. the use of
native plants can sometimes do damage to those species.  We have a native
alder, *Alnus rhombifolia* that became a popular landscape plant in the
70's and 80's.  An insect (genus *Agrilus*) that had formerly co-existed
with the tree in the wild found more food sources in the planted specimens.
Soon the insect was killing alders both in the landscape and in the wild.
(cf. coffee in Ceylon)
        I've always considered this problem so intractable that I've never
thought about potential solutions.  I know that any attempt to change
public taste is certainly futile. In our area I'd love to see increasing
public acceptance of the sparse vegetation of an oak woodland;  urban
homeowners crowd their landscapes to keep up with the Jones or to recreate
the landscapes they knew is wetter parts of the US or abroad.  {A political
point:  I'm a weirdo libertarian so I believe the most fundamental root of
California's problem is the low cost of water:  end of politics}.
        If, somehow, a sparser landscape became fashionable perhaps weedy
escapes would dimish accordingly.  Probably--no certainly--a pipedream.
Jerry Heverly, Oakland,CA
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index