Plants like some of the Ceanothus
range into neighboring states, and although the genetics are not a
perfect match and the plants may not do as well as plants from your
area, they are still closer than plants from other areas that never
grew there. That is, a Black Oak (Quercus
from Eugene, Oregon is going to have different tolerances and
requirements than one found in Mesa Grande in San Diego County. But if
you want to plant a Black
on a north slope in Redlands and you can't find a nursery that grows
any in your area, either the Oregon or San Diego tree would be better
than a Northern Red Oak (Quercus rubra
) from Michigan.
In your garden, the closer you can get to what should grow there, the
less problems you'll have with , soil conditions
temperature, humidity, and herbivores like deer
, etc. Even though Redwood
trees, (Sequoia sempervirens)
are native to California, they can only exist without water in the
areas where they historically grew. Now that is much of the coastal
areas of California from about San Luis Obispo north, but it is not
Bakersfield, Barstow or even Los Angeles. It gets even more ridiculous when planting a native plant from Michigan in your California garden and declaring it native. No, it's not. It's a Michigan native plant,
not a California native plant.
There are a lot of little things that depend on the native plants that are supposed to be in your area. There are bacteria, fungi, bees, butterflies, ants and birds that depend on the native flora of your area to survive. Remove the natives and you remove the birds and butterflies. The common replacements are flies, rats and roaches.