Normal “Abnormalities” – Palms

The Normal

Despite my biases, horticulture is an amazing field of research. I am a horticulturist with a background in Landscape Architecture, whereas a friend of mine is a botanist. Horticulture is the practice of gardening and cultivation while botany is the study of plants. In plant identification, botanists and horticulturalists utilize botanical characteristics to identify specific plants. For example, leaf arrangement on a plant could be opposite, alternate, or whorled.  Different plants have different physical characteristics – enabling us to easily identify plants. While trying to identify a strange plant, I reached out to my botanist friend. He identified it as a Shrimp Plant (Justicia brandegeana). I felt silly because I should have easily been able to identify the plant – but the plant sample did not express the “correct” characteristics of the shrimp plant. The botanist laughed, saying, “Taylor – plants don’t read textbooks. This is an example of a perfectly normal “abnormalities”

The Normal “Abnormalities” Palms

Plants express their “correct”, or mostly normal, characteristics but commonly express perfectly normal “abnormalities.” The “abnormalities” are normal, yet uncommonly seen characteristics of the plants. Since joining Nassau County’s extension office, the most common plant “abnormalities” I experienced involve palm trees. Palms, a general classification for all plants within the botanical family Arecaceae, includes over two hundred genera and 2600 species. The diversity of palms is tremendous, but sometimes we notice the normal abnormalities in palms, which can be concerning to homeowners. The normal abnormalities include the terms, “root problems”, “bark-splitting”, “shedding trunks”, and “leaf scruff”.

Root Problems?

Have you ever looked at a palm and it looks like hundreds of straw-looking roots growing from the palm trunk that would reach down into the ground? During 2022, at our extension office, nearly 30 individuals reached out to our office regarding this issue. These straw-like roots are roots. Palms develop their roots within the “root initiation zone.” The root initiation zone, in some species, can extend several feet up its trunk. Therefore, it is normal for palms to develop roots well above the soil line. Despite its concerning look, it is perfectly normal.

Bark Splitting?

As roots develop from the root initiation zone we may see “bark-splitting”. Bark-splitting is the result of roots pushing outwards on the palm’s bark (cortex). Towards the base of the palm’s trunk, the bark begins to look like it is flaring outwards. On some palms, when the root initiation zone extends higher up the palm’s trunk you may see the palm’s trunk beginning to split.

Shedding Trunks?

Palm fronds connect directly to the trunk. Palms in North Florida typically have palm fronds with “clasping petioles”. A petiole is a technical term for the stalk that joins a leaf to a stem. The fronds clasp onto the palm’s trunk with its petiole. Some palms, like the Cabbage Palm, will completely drop the fronds and petioles which leaves a clean-looking trunk, or it will drop the fronds but keep its petioles. This has concerned many homeowners because their cabbage palm has dropped their petioles while others have not. We do not know why it happens – we believe it is just a random genetic expression of the palm. Additionally, as Mexican Fan Palms (Washintonia robusta) age they randomly drop their petioles, leaving random bare spots along the trunk. I refer to this as their “awkward teenage years.” This is 100% normal, but can be alarming to homeowners.

Leaf Scruff?

Lastly, “leaf scruff” looks like a palm’s “5 o’clock shadow”. These white/black specks along the palm’s fronds immediately make homeowners believe their palm has scale insects or sooty mold. Sooty mold grows on insect waste. Usually, when we see sooty mold, it indicates insects like aphids or scales are present on a plant. Scale insects occur on palms and can cause damage and stress to the palm. Leaf scruff looks similar to scale insects and sooty mold but is usually located along the frond’s rachis (stem) or the base of the petiole. These normal abnormalities do not impact the palm and usually go away.

Celebrate!

Horticulture is a weird, wild, wacky world. It is important to remember that plants do not always read textbooks. Therefore, when we investigate possible issues with our plants, including palms, “normal” is a very subjective term and what we are experiencing may be that plant’s unique, genetic expression worth celebrating. These are perfectly normal “abnormalities”.

More Information

UF/IFAS Extension Nassau County

UF/IFAS Extension Blogs – Taylor Clem

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Posted: May 5, 2023


Category: Florida-Friendly Landscaping, Home Landscapes, UF/IFAS Extension
Tags: FFL, Florida-Friendly, Palms


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