What should I do about these spots on the leaves of a palm? - Ask Extension
Hello! I recently received a plam (I believe either a kentia or majesty, but the specific species is unclear). I noticed there were spots on the palms...
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What should I do about these spots on the leaves of a palm? #717824
Asked August 26, 2020, 12:44 PM EDT
Hello! I recently received a plam (I believe either a kentia or majesty, but the specific species is unclear). I noticed there were spots on the palms leaves. What (if anything) should I do about them? Some of the leaves have many spots, some have just a few and a few leaves do not have spots yet. I have also noticed some minor spotting on the stalks as well.
Howard County Maryland
Expert Response
The spots may be due to a number of environmental exposures or possibly pest or disease. (We do not see signs of either, but it can be difficult to diagnose the latter from photos alone.) Leaf-spotting infections aren't common on indoor houseplants because of the drier and somewhat filtered air, but if this plant was kept outdoors at a nursery (likely) before being purchased or sent to the retailer, it could have contracted something then. The spots look minor and probably won't be of concern going forward, but to minimize the chance of spread, do not mist the foliage as leaf wetness promotes conditions conducive to spore germination and penetration of the leaf. (Ambient humidity, such as from a humidifier, is less risky and benefits the plant more than direct misting regardless.)
Several palm species have known sensitivities to leaf-shine products, fertilizer mineral "salt" buildups in the soil, as well as tap water additives like fluoride. They can cause desiccation of the leaf tips, and might also cause spotting in the interior of the leaf (in the case of leaf shine). If the water source is suspect, you can either dilute the tap water with distilled, or switch to another source like a rain barrel or filtered drinking water that has removed these elements. (Make sure that, if you try bottled drinking water, that you don't choose one that contains added sodium, which is often included in small amounts to improve taste. Similarly, household water treated with a water softener, which adds sodium, should not be used.) With regards to leaf shine products, simply don't use them on the palm. With regards to fertilizer, use sparingly, follow the guidance on the package (as frequency and dosing will depend on the formulation), and do not fertilize at all from about mid-autumn to early spring.
As the palm matures more and new leaves are grown, an old leaf or two can be removed if the spotting or tip burn is excessive. Otherwise, if not a major eyesore, keep the foliage until it dies off naturally as plenty of healthy tissue remains which is photosynthesizing and still feeding the plant.
We do not see scale here, but as they can be a common indoor pest and can feed on palms, you can keep an eye out for them in the future, especially on the leaf undersides and main rachis (the center "stem" of the frond - the part of the compound leaf that the leaflets are attached to).
https://extension.umd.edu/hgic/topics/scale-insects-houseplants
Miri
Several palm species have known sensitivities to leaf-shine products, fertilizer mineral "salt" buildups in the soil, as well as tap water additives like fluoride. They can cause desiccation of the leaf tips, and might also cause spotting in the interior of the leaf (in the case of leaf shine). If the water source is suspect, you can either dilute the tap water with distilled, or switch to another source like a rain barrel or filtered drinking water that has removed these elements. (Make sure that, if you try bottled drinking water, that you don't choose one that contains added sodium, which is often included in small amounts to improve taste. Similarly, household water treated with a water softener, which adds sodium, should not be used.) With regards to leaf shine products, simply don't use them on the palm. With regards to fertilizer, use sparingly, follow the guidance on the package (as frequency and dosing will depend on the formulation), and do not fertilize at all from about mid-autumn to early spring.
As the palm matures more and new leaves are grown, an old leaf or two can be removed if the spotting or tip burn is excessive. Otherwise, if not a major eyesore, keep the foliage until it dies off naturally as plenty of healthy tissue remains which is photosynthesizing and still feeding the plant.
We do not see scale here, but as they can be a common indoor pest and can feed on palms, you can keep an eye out for them in the future, especially on the leaf undersides and main rachis (the center "stem" of the frond - the part of the compound leaf that the leaflets are attached to).
https://extension.umd.edu/hgic/topics/scale-insects-houseplants
Miri
