Naturalized Himalayan blackberry is detestably aggressive.

Every palm tree in local landscapes is exotic. Simply put, all palms are originally from somewhere else. The desert fan palm, the only palm that is native to California, came from isolated colonies in desert regions many miles away. In fact, most plants in common landscapes are exotic. Landscapes composed of Californian plants likely include some plants from other regions of California.

With few exceptions, exotic plants are not a problem. However, some of those few exceptions have become very serious problems. Himalayan blackberry, blue gum, silver wattle, pampas grass, giant reed and broom are some of the more notorious examples. They naturalized to become prolific and aggressively invasive weeds. Some are more common than natives in many situations.

Naturalized exotic plants such as these are problems for local ecosystems, even if they do not affect refined landscapes. They compete with native plant species for limited resources, space and pollinators. A lack of pathogens from their homelands can be a distinct advantage. They alter the lifestyles of some of the native fauna. Some enhance the combustibility of the forests they inhabit.

The justifications for importing exotic species are as varied as the species themselves are. It might have been for lumber, forage, fruit, or vegetable production. Giant reed might have arrived here as packing material for cargo from southern Asia. Nonetheless, most naturalized exotic species, including the most aggressively invasive, came here simply for home gardening and landscaping.

Realistically, of all the countless exotic species that came here during the past few centuries, very few naturalized. Fewer are now aggressively invasive. Some with potential to naturalize may not have yet been able to escape the urban situations they inhabit. The problem now is that there are so many more exotic species readily available from all over the World than there has ever been!

Online marketing facilitates procurement of exotic and potentially invasive plant species from other regions, with minimal regard to regulation of such commodities.

6 thoughts on “Exotic Species Can Become Naturalized

    1. Yes, that is so true. They give the rest such a bad reputation. Blue gum is only one of hundreds of species of Eucalyptus, but it is the one that everyone knows as being so very invasive, and big! It is the biggest weed here.

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  1. We have a lot of wild brambles – whether they are native or not, I couldn’t say. I smile when I see one trailing over the path to think rubus are the herbs of the year. I’m rooting for dandelions to get the accolade next year!

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    1. EW! Herb of the year?! How cringe worthy!
      However, there are many species of Rubus, and technically, even the bad ones are very useful for herbal applications. I sort of think of that as I pull the Himalayan blackberry burls out, but I get over it real quick. There is SO much of it, that there will never be any shortage. Incidentally, there happens to be some of the native blackberry across the driveway which I am taking a liking too. I don’t know why, but the Himalayan blackberry has not gotten over there yet. I am inclined to prune the natives off the fence, but otherwise leave them alone. They are sort of pretty, and I just might want to cultivate them someday. They are not very productive, but hey, they are there, and are undemanding.

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      1. There is a patch of thornless bramble near here, but they are a garden variety gone wild, not the wickedly aggressive Himalayan bramble. Garden varieties, as well as the native species are relatively docile.

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