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Introduction to the Araucaceae- wonderful conifers from down under

By Geoff Stein (palmbobMay 18, 2008
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The members of the Araucaceae are beautiful and majestic trees and many just happen to grow well where I live in California. The following is an introduction to some of the more common species and a little cultivational information.

Gardening picture 

Where I live in Southern California we are somewhat limited as to the number and variety of conifers that grow well here.  There are still dozens, if not hundreds that one can grow, but many of the most ornamental species do much better in colder climates.  Some of the species I grew up with in the Rocky Mountains just cannot survive our overly hot, dry summers and decline rapidly.  Not being a conifer enthusiast anyway, I have not been overly concerned by this fact.  But when I discovered the existence of many odd and highly ornamental pine-like trees at the local arboretums I decided to find out more about these trees and add them to my already cramped collection of plant material.  I learned that nearly all the trees I was interested in growing belonged to the same primarily Australian family of trees- the Ararucariaceae. 

 Image Ponderosa pines have great looking trunks, but I can't grow them here

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Pinus canariensis are the typical pines grown around Los Angeles; Araucaria bidwilliis in southern California- note the incredible difference in terms of symmetry with this family of 'pine' tree

The Araucarias and related species in this family are some of the oldest, most primitive trees on earth.  The Wollemi pine, a recently discovered relict from before the time of the dinosaurs, is just one example of the wonderful trees included in this family.  It is a weird family geographically, with the majority of members living in Australia and nearby New Zealand, New Caledonia and New Guinea.  But some species grow only in South America. 

 Image Wollemia fossil (photo Stevenova)

For the most part these are tall (some as tall as 200'), upright narrow trees with thick, plastic-like leaves, many sharp and overlapping sort of like reptile scales, quite unlike the ‘needles' found on most other conifers.  Most are dioecious (each tree is either a male or a female) though supposedly there are some monoecious individuals out there, and even some that change sex at some point in their lives.  Their cones are small up to massive in some species, weighing many pounds and providing significant danger to those walking below.

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Agathis in Huntington Gardens over 100' tall; overlapping leaves of Araucaria araucana (photo by cristina) and Araucaria bidwillii cone (photo by katrinas)

Most Araucarias are somewhat tropical in their needs and have little tolerance for very cold weather.  Many are even too cold sensitive to grow in southern California where the winters rarely see temps below 25F.  The South American species are somewhat of an exception growing best in colder climates, and struggle in most southern California areas except the mildest, coolest coastal climes.  These species perform far better up north into Oregon and Washington, and perhaps along the east coast as well.

Image my own Araucaria columnaris (sold as heterophylla) fried by freeze down to 27F... it recovered, though

Other genera aside from Araucaria include Agathis and Wollemia.  There are about a dozen or more species of Agathis, most very rare in cultivation, and just one species of the ancient genus Wollemia.  Fortunately Wollemia and at least 2 or 3 Agathis also grow well in southern California, so I am able to add members of all three genera to my little collection.

The following is a discussion of some of the more commonly grown species in this family.

Agathis robusta, the Queensland Kauri, is by far the more commonly grown Agathis species outside Australia.  This is a massive tree growing up to 200' or more.  The first time I saw these trees at the Huntington gardens near Pasadena I was awestruck at their size and shape.  They shoot straight up towering above all else and form a narrow column with only the hint of some lateral branches beyond more than 10' feet from the trunk.  The leaves of this species are thick, shiny and plastic-like, and nearly impossible to distinguish from some Cycad leaves.  It makes me think of it as a monolithic cycad.  The trunk is mottled and ornamental, too.  Good tree for my yard- takes up almost no lateral room, but I have no limitations to height (that I know of... guess the city will tell me once it gets tall enough).

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Three different Agathis robustas (two growing in southern California, one in Hawaii)

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Shots closer and closer to group of trees in southern California

Image Image Trunk/ new leaves (2nd photo katrinas)

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The Bull Kauri is the next most commonly grown Agathis in California... but still quite rare: photos of Agathis microstachya (first photo by kennedyh of Australian tree)

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Agathis robusta in habitat, Australia (photo by Kennedyh); Agathis palmerstonii in Hawaii (this 'species' may be a synonym for Agathis robusta)

Araucaria angustifolia, the Brazilian Monkey Puzzle Tree, is Brazil's only ‘pine' tree.  This is another massive, tall tree (over 100' tall), at least in Brazil.  This is supposed to be a pretty cold hardy tree and dislikes tropical climates, though it seems to tolerate some of the hot drier ones like we have here in southern California.  Still, it looks far more ornamental in its native, highland Brazilian climates where it rarely gets warm, but doesn't really snow much, either.  So it seems to have a fairly narrow ideal temperature range.  Grown ideally, it has a marvelous silhouette nearly the opposite of most classic conifers- it's the top branches that have the greatest spread, and older trees have a nearly flattened top.  The lower trunk loses its branches making the tree look sort of top heavy.  In California this tree is a bit ratty looking, either due to excessive heat or winds.  Leaves are tightly overlapping, triangular, stiff and plastic-like ending in a fairly sharp tip, though not as painfully sharp as some other species (notably Araucaria bidwillii or araucana).

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Araucaria angustifolia in Brazil- first two photos (thanks Gustichock & Monocromatico);  photo of Araucaria angustifolia in S. California

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                           branches, leaves and trunk of Araucaria angustifolia outside its native Brazil (in southern California)

Araucaria araucana is the well known Monkey Puzzle tree, and to me, the most ornamental of all the Araucaceae.  Sadly this is one of the harder ones to grow here in southern California except along the coolest coastal areas.  Temperatures over 80F really stress this plant out, and if occur repeatedly, will usually kill it off.  However, it is supposedly cold tolerant down to about 5F.  This tree is one of the most symmetrical-growing of all conifers, not only forming a perfect ‘Christmas tree shape' when younger, and a more unusual half-dome shaped tree in maturity.  But even the branches and leaves themselves are arranged in a neat, orderly, impossibly symmetrical pattern.  The leaves are triangular, thick, plastic-like and very sharp indeed.  Branches are relatively thick, too, and are covered nearly entirely with leaves all the way to the trunk, which itself is covered with leaves, too, while young.  It is supposedly named Monkey Puzzle as some remarked that even a monkey would be puzzled as to how to climb this tree (spiny all over).

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                      Araucaria araucanas in Oregon, Brazil, and Ireland (second photo by Gustichock and third by KMAC- thanks)

Image Image Image photo cristina

Araucaria araucana branches, closer branches and close up of stems, showing why a monkey might not want to climb this tree

Image trunk showing classic rings found on many Araucaria species (photo KMAC)

Note: do not confuse this tree with the False Monkey Puzzle tree, or Bunya Bunya (see below), a very common tree in cultivation all throughout California in the warmer snow-free climates.

Araucaria bidwillii, also called the Bunya Bunya or False Monkey Puzzle tree, is an Australian native with a much warmer climate preference than the above two trees.  This species is adapted perfectly to where I live- hot, dry and never snows (I hope).  It too is a massive tree and can grow well over 100' tall (up to 180' in its native Queensland).  This tree is wonderfully ornamental and has an unusual shape for a conifer (compared to our native conifers that is) with branches tending to come off at regular intervals at the same level all the way around the trunk giving the tree a sort of ‘created' look (far to symmetrical to be real?).  This is a moderately fast growing tree for a conifer, and picks up speed the older and larger it gets.  Older trees tend to lose some of the lowest branches, but these retain the conical shape (unlike the two South American species above).  The branches of this tree are covered with a rough, peeling bark with occasional leaves arising right out of them here and there (and sometimes along the trunk in younger specimens).  Leaves are overlapping, firm, plastic-like, triangular and incredibly, noxiously sharp.  This is another tree one should really use gloves to prune or handle.  Cones of this tree are massive and can pose serious safety threats to people below.  Fortunately for me it usually takes over 50 years for a tree to get old enough to start making cones, so I'm safe for now (from lawsuits, that is). This is a beautiful tree, but certainly comes its with hazards.  From a landscaping point of view, this tree is huge- laterally as well as tall, and demands a lot of room.  There are several other better choices of Araucaria if one is short on space.

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                     Araucaria bidwilliis in Southern California, including my own young plant in last photo

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                                                         Trunk, branches and leaves of Araucaria bidwillii

Image young by still heavy cone (photo Ginger79- thanks)

For some reason, probably the name False Monkey Puzzle Tree, this tree is often confused with the true Monkey Puzzle tree, a tree that really looks very little like this one.  The easiest way to tell if you are looking at one of these two species is to note what climate you are in.  There is only the smallest overlap in climates in which these two species can coexist, at least here in the US.  If it snows where you are or gets bitterly cold for much of the year, you are looking at Araucaria araucana.  If it never snows where you are and rarely gets below freezing, you are looking at Araucaria bidwillii.  If it gets blazing hot where you are, you are still looking at Araucaria bidwillii.  Then you can look at the tree more closely.  If all the branches (not just the lateral ones) are covered with a thick layer of spiny leaves and look almost the same diameter from beginning to end, you are looking at an Araucaria araucana.  If there are giant cones on the ground, you are looking at an Araucaria bidwillii.  Hope that helps some.

Araucaria columnaris, or Cook's Pine, is a New Caledonian native that surprisingly seems pretty well adapted to the southern California climate despite its tropical origins.  It is a very tall tree, up to 150', and has the classic narrow conical shape of standard conifers we are used to in the US (perhaps a bit exaggerated on the tall part).  It is a pretty rare tree in cultivation here but is a great one to grow as long as you live in a nearly frost-free zone (doesn't tolerate temps much below 27F).  However it is ideally suited for tropical climates and is a very commonly grown tree in Hawaii, where it forms massive stands in some of the botanical gardens there.  It is a ‘user-friendly' tree having smallish cones and soft, small, harmless leaves. 

Araucaria columnaris is VERY similar in many respects to Araucaria heterophylla.  In fact, as young trees, they are virtually identical, and many 'Christmas Trees' sold as Araucaria heterophylla are indeed Araucaria columnaris.  As adults, they can be mixed up, still, particularly as both these trees can vary signifigantly depending upon their environment (humid, hot, cold, windy etc.).  But in general, Araucaria columnaris tends to grow a bit 'off to one side' (leans a bit when young) while Araucaria heterophylla does not.  Also, Araucaria columnaris has a flaky peeling bark while Araucaria heterophylla does not.  And Araucaria columnaris has more closely spaced branches,  then tend to droop near their ends, and eventually break off in taller trees leaving a more columnar look, while Araucaria heterophylla branches grow a remarkable distance apart and remain intact creating a perfect triangle.  It seems most Araucaria heterophyllas grown in cultivation are indeed Araucaria columnaris.

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                             Araucaria columnaris in southern California, Hawaii (thanks htop) and close up of trunk

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                          Araucaria columnaris again, and in Huntington Gardens, California second shot, and view of leaves

Araucaria cunninghammii, or the Hoop Pine (also called Colonial Pine, Queensland Pine or Moreton Bay Pine), is another Australian native.  This is another tall tree (up to 200') but one that is mostly up and down with little lateral space taken up.  This tree, unlike the three previously discussed Araucarias, is not nearly as ornamentally symmetrical and branches seemed to arise more randomly and have less perfectly arranged foliage.  Though many Araucarias have trunks with circular bands around them, this one was named for these bands, or ‘hoops'.   Though this tree is not nearly as attractive as some other Araucarias it does have the distinct advantage of being ‘user-friendly'.  In other words, it is not a hazardous tree- no large, heavy plummeting cones, and the leaves are small, soft, very closely spaced and very comfortable to handle.  It sounds, and somewhat resembles, the Cook pine of New Caledonia.  In fact, I am not sure I could tell the two apart if they were set right in front of me.  I think the Cook Pine has less ‘hoops' around its trunk, though.  This is not a common tree in cultivation here in California, perhaps due to its less than exciting landscape appeal, but it seems pretty well suited to our southern California climate.  Cold tolerance is about to 22F. 

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Araucaria cunninghammiis, young in Australia (photo kennedyh); trunk in Australia (photo ginger749); and tree in southern California

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                                                                                             Araucaria cunninghammii branches and leaves

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                                                                       more shots of Araucaria cunninghammii branches, and cone

Araucaria heterophylla, or Norfolk Island Pine, has already been discussed in a previous article about indoor Christmas palms.  This is one of the smaller Araucarias, at least here in California where it seems unable to reach its potential like it does in a tropical climate (such as Hawaii or south Florida).  This is probably the most commonly grown member of the Araucariaceae in cultivation.  It is sold in huge numbers as in indoor Christmas tree, and as a landscape tree in frost free zones all across the US.  For those who want a user-friendly (at least in terms of leaves not being sharp), smaller tree that will never get out of control, and you live in the warmer western US, this might be a good choice for you.  Here in southern California most do not grow much over 60'.  They make a ‘cute' symmetrical tree, though they usually end up leaning a bit (depends on the direction of the strongest winds).  However, in the eastern US this is a much faster grower and becomes a much larger tree growing as tall as 150'.  The problem with that is this is also a pretty weak tree, and hurricanes easily topple them, or rip of their weak, floppy branches, making the trees a hazard in inclement weather.  In Hawaii, where there are less hurricanes, this tree is still a bit of a problem as it has become a minor weed in some areas (still considered a low risk problem, though).  The name of this tree refers to its leaves.  Juvenile trees have needle-like leaves, though they are soft and pretty harmless.  But as the tree ages the leaves become much more closely spaced and flatter, more scale-like.  So it has heterogeneous leaves depending upon its age, hence the name heterophylla (note: Araucaria columnaris have these heterogernous leaves as well, further adding to the confusion between these two species).  This is not a very cold hardy palm, and mine got severely burned during our freeze a few years ago (lost 90% of its leaves at about 27F, though recovered).  One can see that freezes don't occur commonly here in Los Angeles are there are many mature trees in the landscape.  A freeze in the low 20s would probably kill most of these trees I would think.  However I do not know if defoliating at one temperature allows one to assume death not too far below that. 

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                           Araucaria heterophylla in California, Hawaii (these may actually be A columnaris), and trunk in Australia (last photo GranvilleSouth)

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                          needles/leaves of young trees (first two photos by Xenomorph, and last by Equilibrium- thanks!)

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Adult leaf shape and pattern, along with cones (first photo junglebob, and second pdb-bermudiana)

There are many other species of Araucaria, but most are far less common in cultivation.  Here are a few photos of some of the other species.

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Araucaria huntsteinii, seen in Hawaii... this one may be too tropical for us here in California (from New Guinea) but I don't know if anyone's tried it yet

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     Araucaria montana doing well in southern California (from New Caledonia), in botanical garden (I have no photos of mature trees)

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Araucaria muelleri is another New Caledonian species that looks promising for southern California (this one in Pasadena, California)

Image Araucaria laubenfelsii in S. California is another New Caledonian species that looks like it might do well

Wollemia nobilis is probably the most interesting tree of this family, at least scientifically.  This is a species that was around millions of years ago and for a long time just one of the many extinct conifers in the fossil record.  Then someone rediscovered a population of them in some deep crevice in Australia only a couple decades ago and already it has been propagated in large numbers and been made available to collectors and growers all over the globe.  It is a tall (up to 100'), narrow tree with flat needles (nothing painfully sharp about this plant).  Branching is unusual for a conifer in that nearly all branches do not branch again, though occasionally buds will form near the base of one and a second trunk will grow up from that point.  The branches all eventually form a cone at the very ends.   Luckily for me this plant seems pretty well adapted to my climate, handling both the highs and lows (this tree can tolerate some freezing, but not deep freezes) and grows about the same speed as most of my other Araucareacea trees.  But it can be a pricey tree as it is still a highly sought after species.

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Wollemia in the wild, older seedling, and needle detail of older seedling (photos by Stevenova and katrinas)

 

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                                             Seedlings for sale in southern California (all photos of plants at Cycadcenter)

Useful link on Araucaria confusions: http://www.evergreenspecies.com/2009/04/cook-pine-araucaria-columnaris.html


  About Geoff Stein  
Geoff SteinVeterinarian and Exotic Plant Lover... and obsessive, compulsive collector of all oddball tropical and desert plants.

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Discussion about this article:
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Propagating Agathis Colinia_Mckimii 1 17 May 20, 2008 1:54 PM
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