Are palms "invasive species"?

[Eric Hawaii]

This was just a rhetorical question, of course.  I'm not much for jumping on bandwagons, and I'll patiently wait for the day when the bandwagon of invasive-species hype has passed and people start to generally accept that not everything non-native is bad, that much of the drastic change in the world's ecosystems cannot be prevented or corrected at this point (especially not in Hawaii), and that exotic forest is better than no forest at all.  Meanwhile, I take private enjoyment in watching how exotic palms naturalize and spread themselves into Hawaii's newly-evolving lowland forests that no longer host native trees.  I like to think about what things will look like in 100 or 200 more years.  Right now, Roystonea regia (Cuban Royal Palm) is getting well-established in certain localized areas and popping up very majestically amid broadleaf trees (this can be seen on the mauka slopes of Olomana peak on Oahu and on the walls of Nu'uanu Valley behind Honolulu).  Livistona chinensis has become very well-naturalized in many areas.  Phoenix sylvestris (spelling?) is all over the mesic areas.  Some odd species I still can't identify are found here and there along trails (when i get my digital camera soon I'll post pics).  I know some people want to see nothing but Pritchardias (Loulu) in Hawaii's forests, but those days are long over, so get over it. Sorry to be blunt.

[Morabeza]

Aloha Eric,

There are so many invasive species on O`ahu, at least the palm species that are emerging in the non-native forest are not as agressive as dozens of other invasives.

While I don't share the same enthusiasm for the the naturalisation of non-native palms in places like Nu`uanu, I wanted to inquire about the Phoenix you mentioned.  On the thread "CIDP in Hawai`i"  I have been asking if anyone knows what the real name of this Phoenix is that we see sprouting up in mesic areas and growing by the dozens in places like the Ala Wai golf course.  Is it really sylvestris or loureiri or even pusilla or even a hybrid.  

While it's probably impossible to know when this was introduced, it would be really interesting who brought it and when.  Do they have edible dates?  Or perhaps they were brought here for ornamental value.

Jacob

[Walter John]

Haven't alexander palms gone beserk in areas of Hawaii ?

[Kamipalms]

I know the over populated Syagrus romanceurpantsoff have naturalised in my front lawn/garden/neighbouring properties and almost the best part of Perth .

I also understand they are now classified as a weed in QLD

Jason.

[SubTropicRay]

In central Florida, I believe Phoenix reclinata has joined Queen palms and possibly Livistona chinensis on the exotic invasive species list.  Surprisingly, I do not believe Washingtonia robusta has made the list.  The latter seems to be the most prolific of all listed.

[Trópico]

(Ray @ Tampa,Jan. 11 2007,07:17)

QUOTE

In central Florida, I believe Phoenix reclinata has joined Queen palms and possibly Livistona chinensis on the exotic invasive species list.  Surprisingly, I do not believe Washingtonia robusta has made the list.  The latter seems to be the most prolific of all listed.

How do people see Queens, Chinese Fans, or even Washingtonias being invasive in Florida? I've yet to see them growing in Pine/Sabal/Serenoa flatlands where no human hand has planted them. They don't pop up all over the place so how did they make it to the exotic invasive list?

[palmblues]

we find queens sprouting in the darndest places, flat up against walls under the eaves and in the middle of azaleas  ... they do get around ...

[Jeff Searle]

Allthough it sometimes can be pretty to drive along and see hundreds of King or Alexanders that have come up and naturalized in an area. But what happens also is you take a chance on a species of any type of plant becoming the dominant plant and begin choking out more slower growing, native species. The imbalance can have devestating results. And then the issues of a budget to fight in the removal of these plants usually is not there. The melaleuca tree is a perfect example here in south Florida.

Jeff

[redant]

(palmblues @ Jan. 11 2007,08:17)

QUOTE

we find queens sprouting in the darndest places, flat up against walls under the eaves and in the middle of azaleas  ... they do get around ...

In my parts queens seem to struggle for survival if not planted in irrigated areas. They may seem to pop up everywhere on your irrigated lawn but throw some seeds into the pine flatlands and they will not prosper.

[Alan_Tampa]

Tropico, those species made it to the list because (some) FLIPC people are nuts.

Alan

[bgl]

The only palm that I have seen naturalized here on the Big Island is the A. alexandrae, which apparently was introduced about 100 years ago. It can now be seen in numerous areas, primarily along the Hamakua coast north of Hilo, even though you can certainly see a few individuals here and there in other places as well (such as in the Puna district).

This is a few hundred yards inland from Honolii Beach, a few miles north of Hilo (the surfing beach), and the bridge above is Highway 19.

[bgl]

And this is taken from a Highway 19 bridge further up the Hamakua coast, looking up one of the deep gulches. I believe this is close to the 19 mile marker.

(And Eric, yes, I definitely agree - there's no turning back here in Hawaii when it comes to most, or all, of these introduced species. Every now and then someone, obviously with little understanding of reality, suggests that the A. alexendrae palms in the gulches should be removed....).

[Alberto]

(redant @ Jan. 11 2007,10:14)

QUOTE

(palmblues @ Jan. 11 2007,08:17)

QUOTE

we find queens sprouting in the darndest places, flat up against walls under the eaves and in the middle of azaleas  ... they do get around ...

In my parts queens seem to struggle for survival if not planted in irrigated areas. They may seem to pop up everywhere on your irrigated lawn but throw some seeds into the pine flatlands and they will not prosper.

Here the problem are the pine trees. You will see Pinus eliotti etc popping up everywhere,specially in sandier places where the native ´´campos´´ flora,rich in all kind of species,will probably dissapear,over some years.....

 Here I only saw wild  bangalows (kings)naturalizing in the atlantic forest.

[Trópico]

(Eric Hawaii @ Jan. 11 2007,04:16)

QUOTE

I like to think about what things will look like in 100 or 200 more years.

What about a 1000 years; maybe 10,000 years? My guess is that most palm species are going to be such a variable species in themselves due to palm people hand selecting them with certain desired characteristics, very much like the domesticated dog, and eventually will bear little resemblance to their native cousins in their native habitat (if they still exist). Super cold hardy coconuts with red petioles, a trillion varieties of Dypsis lutescens, super fast and cold hardy C. rendas, the possibilities will be limitless.

[Kathy]

(bgl @ Jan. 11 2007,11:59)

QUOTE

The only palm that I have seen naturalized here on the Big Island is the A. alexandrae, which apparently was introduced about 100 years ago. It can now be seen in numerous areas, primarily along the Hamakua coast north of Hilo, even though you can certainly see a few individuals here and there in other places as well (such as in the Puna district).

This is a few hundred yards inland from Honolii Beach, a few miles north of Hilo (the surfing beach), and the bridge above is Highway 19.

They are beautiful, even if alien.  What do you believe they are choking out?  What is rare around that area that cannot take hold?  Were there any Pritchardia there?

[Eric in Orlando]

In Florida, the following palms are listed;

Livistona chinensis

Phoenix reclinata

Ptychosperma elegans

Syagrus romanzoffiana

Washingtonia robusta

They are classified as Category 2 inasives which means;

Category II - Invasive exotics that have increased in abundance or frequency but have not yet altered Florida plant communities to the extent shown by Category I species.  These species may become ranked Category I, if ecological damage is demonstrated.

Category 1 Invasives are the ones causing ecological damage;

Category I - Invasive exotics that are altering native plant communities by displacing native species, changing community structures or ecological functions, or hybridizing with natives. This definition does not rely on the economic severity or geographic range of the problem, but on the documented ecological damage caused.

Other than Washingtonia robusta, I think the others are only naturalizing in moist, hammock areas.

Here is a link to the Florida list;

http://www.fleppc.org/list/05List.htm

[amazondk]

While looking around areas of vegetation around where I live in Manaus it is hard to identify any invasive species of plant taking over spontaneously.  You see bamboo around, but it has been planted.  As to palm trees I can only remember seeing non-native ones where they have been planted.  Granted not many exotic palms are planted except Roystoneas.  Would it be possible that the great diversity of the ecosystem here makes it difficult for exotic species to flourish?  Maybe someone has an idea about this.  

dk

[bgl]

Kathy,

The short answer to your questions is that I don't know! The disappearance of the Pritchardias is a complicated issue, and in many (maybe most) cases I don't believe it had anything to do with new exotic plant species taking over. Rather, it was the introduction of rats and pigs to the islands that usually caused their demise since seeds and seedlings is like candy to these guys!

Something else (native) presumably grew on these steep slopes before the alexandras took over, but what that was, I have no idea!

Bo-Göran

[SubTropicRay]

Eric,

Ptychosperma elegans is actually popping up all over the place in my yard.  Ever since "mom" set seed for the first time in 1999, it has given me many offspring.  For what it's worth, Chamaedorea elegans and seifrizii is a prolific germinator.  If more widely planted, they might make the list too.

Ray

[Alan_Tampa]

Bo, you hit the nail on the head.  Rats and Pigs are very very naughty critters.

Alan

[redant]

I'm very surprised Caryota mitis has not shown up. They are prolific seeders and I have seen the seed germinate and grow even in my mini pine flatlands that I own, which is not irrigated.

[amazondk]

(Alan_Tampa @ Jan. 11 2007,14:21)

QUOTE

Bo, you hit the nail on the head.  Rats and Pigs are very very naughty critters.

Alan

Alan,

You are right they are nasty critters, they come in on the list of nasties right after humans.

dk

[SunnyFl]

(Eric Hawaii @ Jan. 11 2007,04:16)

QUOTE

I'm not much for jumping on bandwagons, and I'll patiently wait for the day when the bandwagon of invasive-species hype has passed

In Florida, you'd be waiting a long time.

With all due respect to those who are concerned about REAL invasive species (Brazilian Pepper, Old-world fern-thing, Kudzu, Air potato, Melaleuca, Casuarina), I think a more important issue with palms OUGHT to be the fact that so many are threatened or endangered in habitat - not that a few of them have cropped up here & there in FL.

[Trópico]

(SunnyFl @ Jan. 11 2007,15:50)

QUOTE

With all due respect to those who are concerned about REAL invasive species (Brazilian Pepper, Old-world fern-thing, Kudzu, Air potato, Melaleuca, Casuarina), I think a more important issue with palms OUGHT to be the fact that so many are threatened or endangered in habitat - not that a few of them have cropped up here & there in FL.

I don't know why, but I see Brazilian Pepper nicely adorning the roadways around where I work. I thought it was illegal to even posess an invasive species, but I don't see anyone doing anything about it except trimming the grass that grows around them!

[chris.oz]

The most invasive species on the planet is us  !    Our food source plants seem rarely to be accused of being invasive either.

[Dave-Vero]

http://www.miamidade.gov/derm/Plants/prohibited_plants.asp

Miami-Dade County in Florida has carefully thought-out invasive plant regs.  Here's the prohibited list:

  Air Potato (Dioscorea bulbifera)

 Australian Pine (Casurina equisetifolia)

 Banyan Fig (Ficus benghalensis)

 Bishopwood (Bischofia javanica)

 Brazilian Jasmine (Jasminum fluminense)

 Brazilian Pepper (Schinus terebinthifolius)

 Burma Reed (Cane Grass) - Neyaudia reynaudiana

 Carrotwood (Cupaniopsis anacardioides)

 Castor Bean (Ricinus communis)

 Catclaw Mimosa (Mimosa pigra)

 Climbing Fern (Lygodium japonicum, Lygodium microphyllum)

 Day Blooming Jasmine (Cestrum diurnum)

 Earleaf Acacia (Acacia auriculiformis)

 Gold Coast Jasmine (Jasminum dichotomum)

 Governor's Plum (Flacourtia indica)

 Indian Rosewood (Dalbergia sissoo)

 Lather Leaf (Colubrina asiatica)

 Lead Tree (Leucaena leucocephala, Leucaena glauca)

 Lofty Fig (Banyan Tree) - Ficus altissima

 Mahoe (Hibiscus tiliaceus)

 Melaleuca (Punk Tree) - Melaleuca quinquenervia, Melaleuca leucadendron

 Napier Grass (Pennisetum purpureum)

 Puncture Vine (Tribulus cistoides)

 Queensland Umbrella Tree (Schefflera actinophylla, Brassaia actinophylla)

 Red Sandalwood (Adenanthera pavonina)

 Seaside Mahoe (Thespesia populnead)

 Shoebutton Ardisia (Ardisia elliptica, Ardisia humilis)

 Tropical Soda Apple (Solanum viarum)

 Woman's Tongue (Albizia lebbeck)

 Woodrose (Merremia tuberosa)  

"Additionally, the County's landscape code regulates a group pf plants called Controlled Species.  These are plants that cannot be planted within 500 feet of the native plant community that it is known to invade"  The only palm is Washingtonia, which is not to be planted near "coastal wetlands & beaches."  

The site also has valuable lists of trees to plant.

A wealth of information on Hawaii's invasive exotics is at http://www.hear.org/.  I think the biggest deal right now is keeping the brown tree snake out.  If I remember correctly, there's also a lot of concern over the possibility that mosquitos may arrive that will thrive at the higher elevations, spreading avian malaria to the native birds, which only persist in mosquito-free areas.

[osideterry]

My house came with a mature Brazilian Cancer, I mean, Pepper.  It sent 1-2" thick runners in all directions, even going under a driveway. When I landscaped 3 years ago, I gave the tree a 10ft circle and dug up 18 inches of the entire yard area it was in. I put a rhizome barrier around the tree's roots and covered its area with river rock within a garden wall. It has been contained ever since.

I didn't see "Tree of Heaven/Ghetto palm" on that list.

[Dave-Vero]

Tree-of-heaven (Ailanthus) doesn't seem to be a problem in Flroida.  Tallow tree (Sapium sebiferum) is a terrible problem in northern Florida, and I've read that it's running amok in Japan, as well.  Its name was changed, apparently recently, to Triadica sebifera.

I think it was Ascension Island in the Atlantic where the British residents (with some help from Kew) planted a cloud forest atop the moutain in the 19th century.  It's thriving, in violation of the notion that components of an ecosystem should have co-evolved.  It's a bit like the low elevation African tulip forests of Puerto Rico and Hawaii.

[Eric Hawaii]

Wow!  So much to reply to, and I'm jumping at the bit to say a few things (It's a tribute to the vivaciousness of this forum that so much has been posted since I started this thread just 24 hours ago)!!!

1) Jacob (Morabeza): I don't know anything about those date palms besides hearing people call them P. sylvestris.  It would indeed be interesting to find out more.

2) Wal: Yes, as "bgl" so photographically pointed out, we also do have Archontophoenix alexandrae! (did i spell that right?) I forgot about them, but suprised I did because we have them in many parts of Oahu's forests too.

3) Ray, Frank, Jeff, Alan, and all ye Floridians: I think Florida is a lot different situation than Hawaii because (if my assumptions are correct) Florida's native species still dominate most of the landscape and are much more resiliant than those of Hawaii.  Hawaii's isolation bred a kind of sensitivity and vulnerability that's pretty unparalleled.  From what I know (which is admittedly little), the invasive species fight makes a lot more sense in places like Florida than it does in Hawaii.  Nonetheless, I'm not surprised if some get carried away there in labeling any successful exotic as "invasive".  That's the trend that I'm calling a bandwagon mentality.

4) bgl and Kathy:  VERY INTERESTING ISSUE HERE!!  Take a look at that picture there of the gorge on the Hamakua coast.  EVERY tree you see in that picture is alien, and that's how the lowland landscape is throughout all of Hawaii.  If these people got their wish in removing those alexander palms, they'd have to also remove those scarlet-flowered African Tulip trees and the Eucalypts on the hilltops as well!  And then what would you have?  A completely deforested landscape and all the soil erosion that goes with it!  If you replanted native trees bit by bit, would they survive the re-invasion of much faster-growing and hardier exotics?  And where would all the manpower and billions of dollars come from?  

As for Pritchardias, there is little doubt they once grew in that spot with the same profusion as the alexander palms there today, but that was centuries ago.  According to archaeological evidence and historical notes, Hawaiians burned down lowland native forest to make room for crops, their introduced species (bananas, malay apples, kukui nut, etc.) spread into the areas not planted, and then the white man came and brought his beasts of burden, which paved the way for new alien species to spread rapidly.

5) Don, you're right about us humans you are!  Also, why don't we see invasive species taking over the Amazon?  Because it's a largely intact native ecosystem full of biodiversity that can hold its own, unlike Hawaii.  It's actually possible that Hawaii's surviving remnants of upland native forest would be better protected from invasion if the lowland areas were made more diverse with more introduced trees and seed dispersers so that no one or few species could create an ologarchy (as we see today) and then easily spread uphill (Just a little hypothesis of mine).

6) Dave-Vero:  Wow, what a list!  Ficus benghalensis (Banyan) too??  You guys must have the requisite fig wasp over there!  Not here in Hawaii.  Only Ficus microcarpa (Chinese Banyan) has run rampant on these isles, because that species' accompanying wasp was brought over.  Yes, Brazilian Pepper ("Christmas Berry") is seen as invasive here, and i'll say it's not an exageration to say so.

Palms, palms, palms.  It's all good, baby baby!

[Eric Hawaii]

I should just add as an endnote that I think some species are DEFINITELY very invasive and capable of wreaking havoc because they can totally monopolize and take over an area, and if they can be controlled or eradicated before they take too secure a hold, then it's certainly worth trying.  But that's a pretty small list of species that meet those criteria.

[amazondk]

I have spent plenty of time in areas where the Brazilian pepper grows as a native on the coast of Sao Paulo, Rio, and Espirito Santo.  It is interesting how the tree not a prevelant species and sort of inconspicuous.  In fact if I remember right in many places you have to look for it a bit to find it.  This is a good example of how natural checks in the native ecosystem keep things in place.

dk

[moonowl]

So. Are we controlling nature? Here's a different perspective:

Enter The Anthropocene!

http://www.earthsky.org/article/humanworld-whatis

Maybe not.

[SunnyFl]

(Eric Hawaii @ Jan. 12 2007,03:03)

QUOTE

From what I know (which is admittedly little), the invasive species fight makes a lot more sense in places like Florida than it does in Hawaii.  Nonetheless, I'm not surprised if some get carried away there in labeling any successful exotic as "invasive".  That's the trend that I'm calling a bandwagon mentality.

That's the problem exactly.  If an "exotic" is successful here, it goes onto the list and is watched for signs of being "invasive."  

There needs to be a balance but so far as I can see, there isn't.  On the one hand, I can see the frustration with the lack of appreciation of native species, of not being able to find our finer native plants readily available in nurseries (I gave up on trying to find a Chionanthus of legal size) and you don't always find the clusias either.  When it comes to native palms, try finding Cocothrinax argentata or T. morrisii - very difficult.  Although they're slow, they're native, so you'd think they'd be more available.  Oddly, the native-only gang doesn't seem to care about them either.  Non-palm people have never even heard of them - yet they're familiar with palms not native to here.

But the other side of the argument, the native-only crowd, goes too far in the other direction.  It's not only got to be native to FL, it has to be native to the precise region of the state and that makes no sense, esp. in areas where the habitat has totally changed.  We're supposed to be xeriscaping (water restrictions are back in Pinellas!) but many of the plants native to Pinellas are water-lovers (since when Eurasians came here, this county was much more wetland).  There's no allowance made for the spread of native species over time either.  And this crowd doesn't appreciate the importance of diversity - when we bring "exotics" in and they are successful, we're doing exactly what nature itself does, via migrating birds, hurricanes, seeds that stick onto animal fur - nature's imperative is for each species to spread itself as far as possible.

Yet all care should be taken to prevent REAL nuisances from spreading and choking the natives out.  A ptychosperma won't do that.  Brazilian Pepper definitely does.

[Alberto]

(Eric Hawaii @ Jan. 12 2007,03:16)

QUOTE

I should just add as an endnote that I think some species are DEFINITELY very invasive and capable of wreaking havoc because they can totally monopolize and take over an area, and if they can be controlled or eradicated before they take too secure a hold, then it's certainly worth trying.  But that's a pretty small list of species that meet those criteria.

Here this species are pine trees.It makes me feel sad to see this cancer plants sowing EVERYWHERE!!!!On rocky places ,in forests,on the´´campos´´,EVERYHERE!

 On the other hand´´aroeiras´´(Schinus terebenthifolius) are part of our ecosystem,and are far from being a problem. I like them because all species of native orchids and other epiphites LOVE to grow on them!!I have even planted a few aroeiras from a different variety that I found 15 km from here.........

[Bilbo]

Wowie and Zowies galore!

Some of us guys in Northern Europe would sure like some of your "weeds".

Unless Ive been guilty of speed reading to excess I saw no mention of Ipomea acuminata: surely the ideal plant IF you dont like your next door neighbours!

I reckon there is sure a lot of truth in the old saying along the lines of  "a weed is only a plant in the wrong place".

Regardez

(I love Ipomeas cos in my climate they are controllable!)

Juan

[Eric in Orlando]

Its funny in a way that Alberto mentions Slash Pine,  Pinus elliottii taking over in his part of Brazil. That is a FL native and its native habitat is one being overrun by Brazilian Pepper. Same with Australia. In the Everglades Melaleuca quinquenervia is smothering out natives but in Australia, Pond-apple (Annona glabra), which grows wild in the Everglades, has become very invasive.

Has any other FL natives become invasive elsewhere? I have read that Seagrape (Coccoloba uvifera) and Red Mangrove (Rhizophora mangle) have naturalized in Hawaii. Have they become invasive? Some FL natives I can think of that would have possibilities include;

Callicarpa americana-Beautyberry

Ficus aurea-Strangler Fig

Hamelia patens-Firebush

Psychotria nervosa-Wild Coffee

[Dave-Vero]

Eric Hawaii,

Fig wasps have indeed arrived in Florida, and Ficus seedlings pop up all over Miami.  Not just the native Ficus aurea (which can sometimes be pretty annoying in a landscaped setting).  

Eric in Orlando's list of possible invasives might be relevant to Australia.  Oddly enough, Hamelia patens is grown as an annual Missouri Botanical Garden.  It's native from Florida and Texas to Paraguay, so it is certainly a common plant in the Americas.  

Most of the Caribbean plants native to Florida are effective colonizers and can recover from freezes, hurricanes, fires, and other disasters.

[Eric Hawaii]

Eric in Orlando:  The seagrape tree is common along the beach strand here on Oahu, but I don't see any indication that it's problematic. I've never seen an area where it has taken over; it grows peacefully alongside the tropical almonds, coconut palms, pandanus, spider lilly, beach heliotrope, milo nut, and beach naupaka that form the typical plant community along the windward coastlines of Oahu.  

The red mangrove is interesting because it has been branded as very invasive, and serious efforts have been made toward its eradication, yet ironically, I've heard about a UH grad student who started out with the intention to show how red mangrove was threatening the local wetlands but then came to develop an appreciation for the species during her research.  She found the mangroves harboring some native animal species and functioning to filter out soil runoff from streams before it got out to sea.  If this is true, it illustrates something that I have been trying to point out to people about alien species, which is that their net ecological effects can be very hard to determine.  An alien species is often harmful in one way yet helpful in another.  Perfect example: the coqui frog has been cursed for a variety of things in Hawaii, among them its potential to eat native bugs.  But the coqui also eats lots of unwanted invasive bugs, some of which threaten the native ones through competition and predation.  So what's the net ecological effect of the coqui frog in Hawaii?  I don't know if anyone can say.

SunnyFl:  Thanks for your thoughts, and I think you put it very well.  

Dave-Vero:  Interesting how many of Florida's native trees are decidedly tropical and also native to areas of the Caribbean much closer to the equator.  I think south Florida's climate may be more tropical than one might expect for its latitude.  Perhaps this is due to the exceptionally warm ocean there?  Alberto may be able to confirm or deny my assumption that the same latitude (25 to 27 degrees) in southern Brazil borders much cooler ocean temps, and I suspect that part of Brazil can't grow coconuts as well as the same latitude in Florida.  Alberto?

[amazondk]

Eric,

92 percent of Brazil is above the line of the Tropic of Capricorn.  I just read that in something I was reading about Brazilian climates and thought it was interesting.  The big difference with the coast of Southern Brazil and the coast of Florida is that it has a cold water current coming from Antarctica running along it quite far to the north.  The water even in the state of Espirito Santo, north of Rio, is quite cool.  It is relatively common to have penguins wash up on beaches in Rio de Janeiro as well.  

I posted this map on a weather thread, I thought it was interesting.  It shows the climate hardiness zones in South America.  You should be able to see where coconuts will grow here. I am not sure really how far that would be since I have never been to the beaches in the south of the country.   Since South America is an important source of plant species I thought it was relevant.  The zone lines may not be accurate, but I think they are close.

dk

[Dave-Vero]

http://www.globalbioclimatics.org/.  This online climate resource from the Universidad Complutense makes fascinating browsing for the climate freak.  

Surprisingly cold water moves south along the Atlantic coast in winter.  In years past, I recall watching guys in utterly inadequate wetsuits trying to surf 45 degree F (7 degree C) water.  Even Marco Island, at the southwest corner of the state, can have 56/13 degree water in January.  However, the Gulf Stream does help the overall southeaast Florida climate, and the Gulf of Mexico helps protect the Gulf coast.  

The climates of Paraguay and vicinity are good matches to Florida, so it's no wonder that Pinus elliottii (Slash pine) is a problem there.  I can imagine an outbreak of Sabal palmetto.  Conversely, the region offers lots of opportunities for cultivated plants (and invasive species!) for Florida.  

Eric Hawaii--

Bear in mind that the flora of Florida is very heavily temperate until you get to the south tip of the state.  The remarkable Fakahatchee Strand has bald-cypress (Taxodium distichum), ash (Fraxinus), but also pond apple (Annona glabra) and lots of thoroughly tropical orchids and bromeliads.  And royal palms!  The Keys are almost entirely tropical and have many Caribbean species seen nowhere else in the state.  But the royal palm and Acoelorraphe wrightii aren't native to the Keys and the latter is hardy far north of its native range.  The pinelands and hammocks of Miami-Dade County (including Everglades National Park) are nearly as tropical.  All of the tropicals on the mainland can put up with the occasional frost or short freeze.  Trees that can return after being smashed up by a hurricane can also return after suffering some freeze damage.  

Florida's tropical trees and shrubs have highly individualistic distributions within the state.  Ficus aurea, the strangler fig, ranges into St Petersburg and Melbourne and goes well inland.  Sea grape is strictly coastal, as is the beautiful Simpson stopper (Myrcianthes fragrans).

Hawaii's status as an extremely isolated archipelago means that while its native beach flora is pretty cosmopolitan (some species even shared between Florida and Hawaii), the interior flora is the result of rapid evolution from few successful colonizations, so the flora is unique in the same way that the palms of Madagascar are unique, except that Madagascar has (or had) a bigger land base and a longer history.  

Your comment about mangrove in Hawaii is interesting.  The National Wildlife Refuge in Kauai has mangroves at their property on the south shore.  I don't know whether much effort has gone into eradication.  The NWR on the Big Island is, however, restoring forest as bird habitat.