- 2 Aug 2019
Background Sersia lancea, the African sumac, is a common tree around the valley - the strong fragrance of its diminuitive flowers remind me strongly of spring time as a kid growing up in Phoenix. The tree is relatively unassuming, no showy flowers in the spring and no vibrant colours in the fall. Like most invading trees, it was originally brought to the valley in the 60s as a landscape tree. I’d venture to guess that most homes built in the 60s and early 70s had an African sumac planted prominently in the front yard or back yard.
As can probably be deducted from the common name, it is one of the most common trees in South Africa. In the native range, livestock that graze too heavily on the leaves will develop a foul taste in their milk. The bark, leaves, and twigs provided indigenous groups with a valuable source of tannin for leather making.
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- 21 Jul 2019
Background Ailanthus, tree of heaven, paradise tree, or tree of hell (as many like to call it) is an invasive tree across the United States, Canada, and Mexico. First introduced as an ornamental in the Eastern US and brought to California during the gold rush. This tree is common in urban areas and very tolerant of pollution and poor soil conditions. You can see tree of heaven in many mining towns in Arizona, some say it is holding up the old copper mining town of Jerome.
In Phoenix I’ve come across ailanthus in older neighborhoods and I can see its invasive nature by the numerous amount of small trees and sprouts surrounding the larger trees. Tree of heaven is dioecious (trees are either male or female), the male flowers have a very offensive odor. Crushed leaflets smell like peanuts to some.
The numerous seeds produced by ailanthus are only viable for 1 year and they spread by wind, water, birds, and humans.
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- 19 Jul 2019
Background Lead tree, river tamarind, faux mimosa - Travel through just about any alleyway in the Phoenix metro area and you are sure to come across this tree. It will usually be loaded with reddish, thin seedpods and likely have many small lead trees around it. Native to southern Mexico, it was originally planted as an ornamental here during the 1970s and 1980s. Supposedly, the tree was promoted as a “miracle tree” with many uses for the pods and wood. The bark (like many trees) was used in folk medicine to help relieve pain. Some Asian countries (particularly Laos and Indonesia) imported it and incorporated its prolific seed pods into various food dishes. The pods have also been used as a high protein animal fodder - until it became known that it causes hair loss in donkeys and horses.
The trees grow unbelievably fast and spread quickly - trees less than a year old can produce copious amounts of viable seedpods that will grow wherever they touch soil.
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