Pictured above are a few Acacia Salicina, AKA "Willow Acacia". I took these particular pictures in Gilbert, but it is not unusual to see them used throughout newer (1-20 years old) developments in Mesa, Chandler, Scottsdale, and others, both residential and commercial. Very often, I would say 1/3, or more, they look like the ones above. For some reason they are used as parking lot and street trees a lot. I just don't get it.
OK, so before I go on breaking down just how bad of a choice planting these trees in Arizona Landscapes can be -especially in above mentioned situations- let me say that every tree has it's place and I am not knocking the tree, the way in which it is used. The trees don't choose where and by whom they are planted !
Cons to Acacia Salicina for city use:
1. Require a lot of trimming/maintenance (which also means lots of man-power, dump trips, etc)
2. Branches are quite likely to break in the wind because of rapid, erratic growth
3. VERY shallow (and invasive) root system (you can see the surface root top left, just waiting for a combination of rain and wind - hmmm... Arizona Monsoons? This is one of the most common trees you see blown over during "micro bursts" or even moderate storms)
4. Inconsistent growth rates, inconsistent structures in general. Not a plus for a city street tree or providing shade.
5. Consistently produce pollen, pods, cycle through leaves, creating a need for more maintenance, clean-up, gas blowers, dump trips, etc. (mess level - 8.5/10)
So after all this hard work, keeping it in line, cleaning up, dealing with emergency service bills ($) for broken branches and fallen trees, here is the toughest part to swallow.......drum roll......
A lot of these trees, after all the investment our tax dollars (or personal dollars) and the energy of the maintenance crews put in..... A very large amount of them will have to be replaced, thus requiring costs of removal -labor, hauling, dump again, costs of buying a new tree, labor to plant it. And finally our city's or our neighborhood's maturity and character (which is SO essential, especially in the rapidly growing, culture struggling to keep up Valley we live in) starts all over after all this work ! And it's quite possible the replacement could be another Salicina !
Now I am feeling bad for harping on the tree. It didn't decide to come from Australia to Arizona. Somebody realized they were easy to grow, fast growing, and inexpensive. ($$) This is similar to what seems to have been a Eucalyptus craze in the eighties. And the more current Sissoo over-use :)
I will end with some pro's: fast growing, beautiful weeping look, great for farms or riversides, especially in Australia :) See, isn't that better !
Adam Bruce
PS - I don't want to be cynical often in this blog, but this has been bothering me for about a decade. Please hire a professional to help you select trees and locations, it makes a big difference for all of our futures.
PSS - Another culprit with strikingly similar issues is the Chilean Mesquite (there are many types of Mesquites that grow well here and are reliable, it's just this particular one and it's over-use that is many times a true waste of resources)
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You are so right about trees. All trees drop something, leaves, flowers, seed pods, but the trick is to find a tree that doesn't drop much. If you have a tree you want removed check out Phoenix Tree Removal.
ReplyDeleteSo Adam, what other trees should we avoid planting in our front yard? I don't have a business to shill, I really want an answer. Did you write more blog posts? I can tell you from our experience, Mexican palo verde and shoestring acacia are high-litter trees and should never be planted in a suburban yard. Now we need a replacement. Help?
ReplyDeleteThis acacia variety is indeed destructive. When we bought our home in 2000 and noticed a tiny seedling growing in a narrow 20" wide space between our pool deck and our block home.
ReplyDeleteI should have removed the tiny tree when it was the size of a pencil but waited 24 years to cut it down after it lifted our pool slab 4 inches, sent root systems 30 feet away with suckers that pop up everywhere like the invasive sisu does.
The tree had added a lot of organic material to our pool constantly especially after the tiny yellow pom blooms and seed pods that followed. This cost us a lot in pool upkeep as the phosphate levels elevated causing us to use more chlorine to control the algae to form prolifically.
price to remove was $2300 to $2800 We decided to just remove limbs from the top and work our way down till it was finally gone. The final trunk diameter was 18" .
After some homework we found that had if we cut the large tree into long pieces, we could have sold it as an exotic hardwood that is beautiful light and dark reddish to pink colors cherished by wood workers to make furniture, cutting boards and other decorative pieces.
We also learned that Acacia is one of the exotic smoking hardwoods used for flavoring meat in smokers. It has a mildly sweet essence, ideal for fish, chicken or pork.
Though an awesome shade tree that grew quite fast, you need to understand the downside of this tree. So if you just dread getting rid of of this invasive tree you might just recapture your removal cost selling the wood to the right person.
if anyone is interested in buying any of my now valuable stash let me know.