This blog is about growing tropical-looking plants in the Phoenix, Arizona area

April 11, 2013

A close look at the largest cycad in the United States

All cycad collectors know that the age of the plant is determined by the size of the trunk (technically called the "caudex"). On smaller cycads, the caudex is sometimes referred to as "the pineapple" as it's less of a trunk and more of a, well, pineapple shape. It's impossible to determine the exact age of a cycad. Unlike most trees, there are no "rings" to count in the trunk. And cycads grow at different rates, depending on conditions. Most put out a flush of leaves once a year, but under ideal conditions, they can grow faster.

The one pictured here, a dioon spinulosum, has the longest trunk of any cycad in the United States. It was collected in Mexico as an adult around the year 1900 by oil tycoon Edward Doheny. It was planted in this little park in Los Angeles in the 1950s when it was about 25 feet high. It is now about 40 feet tall.

Standing under it, and next to it, was quite amazing for me. What caught my eye was the lack of the persistent leaf-marks (they usually look like little diamonds) on the trunk. These are the marks left where the base of the frond had been. Although the trunk is certainly not smooth, there are no persistent leaf-marks on it. It looks like the trunk of an ordinary tree, not a palm or any of the cycads that I have ever seen.

This post is written in memory of my friend Dutch Vandervort, who shared this information with me.

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