Saturday, February 27, 2016

Trees for Perth

A reader asked me to list what trees I think we should be planting in Perth. 

Here are my "indispensables" *...

BIG TREES (the most important category because we need canopy)

Liquidambar (Liquidambar styraciflua)
London Plane (Platanus x acerifolia)
Flame tree (Erythrina x sykesii)
Lemon-scented Gum (Corymbia citriodora)
Spotted Gum (Corymbia maculata)
Marri (Corymbia calophylla) - where honky nuts won't be a problem
Peppermint Gum (Eucalyptus nicholli)
Tuart (Eucalyptus gomphocephala)
Sydney Red Gum (Angophora costata)
Camphor Laurel (Cinnamomum camphora)
Port Jackson Fig (Ficus rubiginosa) - where large buttress roots won't be a problem
Moreton Bay Fig (Ficus macrophylla) - where large buttress roots won't be a problem
Norfolk Island Pine** (Araucaria heterophylla)
Sheoak (Casuarina equisetifolia) - where vigorous roots and heavy needle-shedding isn't a problem


MEDIUM TREES
Poinciana (Delonix regia)
Jacaranda (Jacaranda mimosaefolia) - Hills only
Cape Lilac (Melia azedarach) - once the caterpillar problem is resolved
Brazillian Pepper (Schinus molle)
Iron Bark (Eucalyptus sideroxylon 'Rosea')
Tipuana (Tipuana tipu) - where vigorous roots won't be a problem
WA Peppermint (Agonis flexuosa)
Chinese Elm (Ulmus parvifolia)
Claret Ash (Fraxinus 'Raywood')
Paperbark (Melaleuca quinquenervia) - where vigorous roots won't be a problem
Honey Locust (Gleditsia triacanthos inermis 'Sunburst') - just need to clean up the large seed pods
Holly Oak (Quercus ilex)
Cork Oak (Quercus suber)
Carob (Ceratonia siliqua)
Queensland Box (Lophostemon confertus)  - still thinking about this one


SMALL TREES
I'm not going to list any because we need to stop using them! ***

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* There will be other trees that come to me (or readers send in) so I'll update and re-post this list from time to time but right now these are the trees I would pin my life on.

** Not really a canopy tree but so iconic you have to include it. However I would only use it in irrigated areas now as it doesn't seem to be coping too well with our declining rainfall.

*** OK, there's a time and place. A small courtyard might suit a Chinese Tallow or Crepe Myrtle or something but this blog's about street trees and I don't want to encourage any more small trees in our streets as it's always a wasted opportunity.

4 comments:

  1. Sadly sometimes "large" trees behave small due to dud quality of nursery stock, poor soil or careless planting - LGAs need to work on that. Great list - the contentious one for me would be the lemon scented gum - maybe better suited to parkland situation than as a street tree to let it express it's majesty, but as most Perth examples are circa 1970s and have had dodgy pruning (lower laterals removed etc) they have been given a bad name. Often overlooked are Casuarinas - we have some very fine endemic ones, some salt and drought tolerant. Not always big on shade but neither are Eucs when they cringe in summer. Schinus molle isn't the Brazilian Pepper, that would be terebinthifolius - they are both fantastic trees however, family favourites (with aromatic fruit!) but the latter is better for shade & pruning tolerance (and for kids to climb). Some beaut examples of molle in Dongara showing their resilience.
    And I would add Gleditsia to the list :) And Quercus suber. And Olea. And Macadamia. A place for small trees in streets is where you might use shade umbrellas - in pots / containers, outdoor cafe situations, pedestrian malls, decorative, semi portable and with the understanding that they have a 'shelf life' or may be rented out. Small / med trees suggest maybe Pyrus (although I saw a crook one today for the first time) they are generally quite drought tolerant and don't go crispy brown late summer like Platanus. Ficus platypoda (rock fig) Ficus carica (edible fig). Edible trees that's a whole other conversation :)

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  2. My recent discussions of Lemon-scented Gum with various people have convinced me it should be on the list. You're right, early practices with the tree have probably (unfairly) given it a bad name but also I've been convinced that it's pretty much trouble-free for the first thirty years of it's life. The Arborist who convinced me said that, if anything, Spotted Gum - the similar tree that is widely considered "safer" by us Parks folks - is probably MORE likely to shed limbs (!).

    Regarding Schinus: common names are always problematic as it often depends on what neighbourhood you grew up in! In the local Parks industry, S.terebinthifolius was the "Japanese Pepper", not Brazilian. Maybe times have changed? Anyway, I would still have a problem with using S.terebinthifolius because of its multi-trunked habit compared to the single trunk of S.molle; that and the fact that S.terebinthifolius seeds prolifically, popping up in people's garden beds etc.

    I hear you about Casuarina. I was sorely tempted to put C.equisetifolia on the list and refer in an earlier post to it's usefulness in locations where it's anti-social habits aren't a problem but decided in the end to leave it off because it's applications in suburban Perth are probably just too few. However, you've convinced me. On the list it will go with a suitable qualifier :)

    Gleditsia triacanthos 'Sunburst' was also definitely close to inclusion. I left it off in the end because the only ones I'm familiar with are not particularly large (ie they're bordering on "small tree" to me?) but also because the very large seed pods caused us endless grief as Parks people (resident complaints). But it's just one of those annoyances that we probably have to learn to deal with now in the interests of increasing our urban forest diversity now. I'll add it to the list!

    Quercus…yes. Some good ones for sure. The Cork Oak (Q.suber) as you say and also the Holly Oak (Quercus ilex). Slowness of growth made me leave them off but I think you're right - they should go the list too.

    I left Olive off because they're just don't produce sufficient canopy in sufficient time frame for me.

    And finally those small tree applications you mention are all valid - I would add Oleander in there too - but I really want Councils to focus on CANOPY so deliberately didn't get into that area.

    Thanks for your comments - very useful!

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    Replies
    1. re 'Sunburst' - no, rather "Shademaster", anything with pale or variegated foliage grows way slower and fares less finely in the heat.
      Rate of growth is one thing - consistency & resilience to urban conditions is another. (ie crap soil) is why olea are worth considering. They can also tolerate pruning, - sh*t happens.
      "Japanese pepper" is a term only understood in Perth I have been told, hence my comment - great trees but the Schinus molle has much value as a potential street tree - it was on the olde Hamel nursery list for LGA use.
      Canopy - think breadth, width, height, density, health… more than just "cover" to it. Some of the Eucs lose a fair bit of their density (leaf drop, adjusted leaf angle) in summer when we need it most, their leaf drop is fine with parkland / mulched garden beneath but resented in suburbia. I reckon a few Gleditsia pods are up with that in the realm of mess, cheers.

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    2. Gleditsia 'Shademaster' - yes, sounds like a better option than 'Sunburst'. Good comments about the Eucs too - I hadn't thought of that. Thanks for sharing your knowledge. Much appreciated!

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