Native or Naturalized?

Yesterday evening, Town Mouse (TM) had an interesting conversation with her imaginary friend Pet Rat (PR).

P.R: Nice photo.
T.M.: Yes, that's a Penstemon heterophyllus (Foothill Penstemon). With that great camera, I'm starting to get some better pictures. I'm even participating in this photo contest by Gardening Gone Wild. This particular contest is for photos of plants that are native in the state.
P.R.: Well, that should be easy. Whatever you see when you go for a walk in the woods or the hills is native.
T.M.: Unfortunately, that's not true. Many plants you see are native, but others might be invasive exotics that are naturalized.
P.R.: Naturalized?
T.M.: Yes. As Wikipedia says, "in biology, naturalisation is the process when foreign or cultivated plants or animals have spread into the wild, where they multiply by natural regeneration. Naturalised species may become invasive species if they become sufficiently abundant to have an adverse effect on native plants and animals."
For example, if you go for a walk around here, you might see forget-me-nots, calla lillies, and vinca major along the streams. Those plants are not native and have crowded out native vegetation. You probably don't see native Iris where the vinca is, it just can't compete.

P.R.: Forget-me-nots? You're kidding. I was sure they were native. So, naturalization sounds like a horrible thing!
T.M.: It all depends. I myself grow daffodils in my garden, and I'm quite happy that they naturalized, which means they multiply every year and I don't have to do anything for them. It all depends on how invasive the plant is and where you live.
P.R.: Well, I buy all my plants from a nursery, I don't just go scatter seeds about, so I should be safe.
T.M.: Don't be so sure. Unfortunately, nurseries are businesses, and they sell plants that are tough and look pretty. Those plants might well be invasive. Think of it, the bugs that live here haven't had enough time to get interested in them, quite in contrast to the natives, which always get nibbled at a bit, and then the owners get a panick attack and don't want that plant again. So, you can buy vinca, cotoneaster, and other invasives in most nurseries.
P.R: Oh no! What am I to do!

T.M.: Go native. Don't you like the Ceanothus Tilden Park above? But there are many attractive and non-invasive non-native plants to choose from. I have lavender, a tea tree, and a butterfly bush in my garden.
I would recommend, though, that you make sure you're not planting an invasive species. If you live in California, you can go to the California Invasive Plant Council web site and check there (we have a clickable link to them at the bottom of our blog). If you live in another state, other plants are invasive. In Oregon, for example, butterfly bush and berbascum are big problems, in most of California it's too dry, they are not a problem. is a good place to start. Or you can just ask a garden designer or a friend that is interested in such topics.
P.R.: Well, at least there are some web sites. Now I feel better, it's not so difficult after all. Still, maybe we can just go to the nursery together next time. I really like the plants you have in your garden. That Triteleia laxa looks great, and it's been blooming for more than a month! Next year I'll get some myself.


Emily said…
Thanks for the tip! I'm bookmarking your links so I can refer to them when we revamp our garden.
Why, I know three real pet rats, but they don't seem to share an interest in gardening. My "issue" is that people still call cultivars of native plants native, and to me, once we start messing with them, they're no longer native.
Tatyana said…
Oh, you hit the nerve! Who came with idea to sell crocosmia?! Ít scares me when I see it spreading in my garden!
Anonymous said…
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You do have the most interesting conversations in your garden! Although I'm not as clever as Pet Rat, I learned a lot--thank you.
Beautiful blues in your photos--and a nice, balanced discussion of natives vs. non-natives. Thanks!
Anonymous said…
Love this post - it's a great explanation on the dangers of exotics, which is often hard for people to grasp.

I'm also pleased to note the high level of technical competence in your household. I'm assuming you have wifi, or how else could your rat go online while relaxing in his rat den? Because it's just silly to think a rat would have electricity.
Congrats on your tritelia and dichelostemma! (I read your Dry Stone comments)

Monica, I'm with you about the cultivar thing, but it gets so confusing. Some named cultivars are actually wild species, they just glamorize them with trade names. Then there are supposed species (I don't know any among Calif. natives, but I do among other natives) which are actually very old hybrids. What's a plant grower to do?