The greenery of the leaves on a Yucca plant is indicative of their energy levels. When the leaves on a Yucca plant are turning yellow, it means that it lacks the energy required for photosynthesis and as a result, won’t grow.
For that reason, the cause of the Yucca plant turning yellow needs to be identified so that the growing conditions can be rectified.
Everything that a plant needs to survive can also be its downfall if the amount of any of its needs are given in abundance or sparingly.
When plant leaves turn yellow, the term used to describe the condition is chlorosis. A lack of light is the most common cause, but any stressor has the same impact.
Give a Yucca plant too much water, not enough light, or an inadequate amount of fertilizer, and the leaves turn yellow. Not only that, but improper acclimation when changing the growing conditions, pests feeding on the leaves of Yuccas, extremely high temperatures and on occasion, transplant shock can cause yellowing leaves, too.
The Causes and Fixes for Yellowing Leaves on Yucca Plants
1 – Lacking the Light That They Need!
Yuccas do well in full sun. The only time be careful of direct sunlight is at the peak of summer, as that’s when the leaves can be burnt. Six hours full sun is optimal. Anything less, growth is slower. Without enough light, that is when problems arise.
Yellow leaves are what happens to plants without sunlight, so keeping a Yucca in the shade will be detrimental to its health. South facing windows are ideal as those get plenty of sunlight.
A north facing window is likely to lack the light requirements a Yucca needs. Leaves yellow because photosynthesis is hindered in low-light conditions.
Without enough light, they lack the ability to produce the sugars required for the plant to produce food for survival. Give your Yucca more light and it’ll soon perk up.
2 – Incorrect Watering (Too Much or Not Enough)
How much water a Yucca plant needs directly correlates to the amount of light it receives. The less light it gets, the less water it needs because it will take longer to dry. Direct sunlight necessitates more water. Low light requires far fewer waterings.
You’ll notice this in the winter months when the soil takes longer to dry because of having less daylight hours, and cooler temperatures. Whatever you find your plant usually drinks, halve it in the winter months.
As Yucca plants are drought-tolerant, they do not need much water. Just enough to keep the soil from completely drying out. It’s fine (and preferred), for the top soil to become dry to the touch (top meaning, the top inch to two inches).
When watering, water until you can see the water draining freely from the hole in the base of the pot, and discard of run-off water.
Don’t return the pot to a saucer containing the drained water. It’ll work its way into the roots and result in over-watering, which is when you’re likely to see the leaves on your Yucca yellow. If not corrected, over-watering will result in root rot.
There are different ways to fix over-watered plants, but for Yuccas, the fastest fix is to remove it from its pot and let it air dry outdoors. Place it in a sunny spot and leave it for a couple of hours, then repot it.
3 – Being Too Generous with Fertilizer
High nitrogen fertilizers are problematic for Yucca plants. They promote fast growth; however, actions have consequences. Grown too fast, leaves are weaker. The leaves will fail to mature properly, resulting in their premature demise.
Rather than aging leaves yellowing and dropping from the base of the plant, all of the leaves can be pale to yellow.
Over-fertilization with any type of fertilizer will cause yellow leaves on Yucca plants, regardless if it is high in nitrogen content or not.
This is because the excess of phosphorous and potassium builds up in the soil, diminishing its quality and damaging the root system. The way to fix fertilizer burn on plants is either to flush the soil to rid the excess salt accumulation, or repot in a fresh potting mix, taking care to avoid transplant shock.
When Yuccas are over-fertilized, damage to the roots can’t be seen directly without removing it from its pot to inspect the roots, but do take note that yellow leaves can be a sign of root damage occurring.
Avoid fertilizing problems by using the right food. Low nitrogen and high potassium and phosphorous fertilizers are preferred for Yucca plants, but that is not your only option.
In terms of what to feed a Yucca plant, there are numerous organic materials that can be used that slowly release the macronutrients and micronutrients that the plant needs. Seaweed extract and bone meal are just two organic fertilizers suited to Yuccas.
4 – Acclimation
Given that Yuccas are not totally hardy, they are frequently kept indoors in the winter then moved to the garden when the better weather arrives.
The instant they are moved, the growing conditions change, and that can stress them. Suddenly, they have more light than usual, some cross wind (draft), lower humidity and variable temperatures (day and night).
When transitioning a Yucca from indoors to outdoor growing in a pot, yellowing leaves can be avoided (somewhat) by slowly acclimating the plant to the outdoor growing conditions.
Do this gradually over 3 to 4 weeks by introducing the plant to the outdoors starting with just a couple of hours a day at the start of spring, then increasing up to six hours of full sun. Some leaves will yellow, but without acclimating the plant, you’ll experience fewer yellowing leaves.
5 – Pests
Pests feed on the sap within the leaves of plants. Since Yuccas store an abundance of water in the leaves, trunk, and rhizomes, they are a target for sap-sucking pests.
Yucca plants with sporadic yellow leaves can be an indication of a pest presence. Where these are feeding on the plant, the leaves will dry out faster than the rest of the plant, and since dry leaves can’t photosynthesize, the leaves turn yellow.
Unlike yellow leaves at the base of the plant, when a pest presence is the cause, you’ll see partial yellowing – some at the top, base, and mostly in the center of the plants leaves close to the veins where most of the water is being transported throughout the plant.
The types of pests that tend to feed on Yuccas include spider mites, aphids, scale bugs, and mealybugs. Common remedies to get rid of bugs on indoor plants such as using Neem oil or taking your plant outdoors and hosing it down are sufficient to rid Yuccas of these types of pests.
In some states, the Yucca weevil can pose problems for outdoor Yuccas. The weevil is the most destructive as that infects the plant with a bacteria. The rest will simply feed on the sap, drain the juices from the plant which dehydrates it, causing the yellow leaves.
6 – Temperatures
Yuccas love arid conditions, but they can be found growing wildly and vigorously in tropical and subtropical regions. That said, some locations can be detrimental for them.
Yuccas thrive in warm arid conditions in temperatures up to 85oF (29oC). Indoors, temperatures don’t exceed that, but, it can on the leaf surface. Placed in direct sunlight close to a window, the glass magnifies heat and that can lead to sunburn.
Leaf scorch on Yucca plants causes brown leaves. Before they brown though, the leaves can take on some yellow spotting, before becoming scorched.
If you have your Yucca placed in direct sunlight year-round, then on hot summer days when temperatures are heating up to extreme levels, it may be necessary to apply a shade cloth to a window to prevent leaf burn, or turn on fans to cool the room down.
For outdoor Yuccas, some shade on hot summer days can prevent the leaf surface temperature reaching excessive highs, which will deplete its energy levels fast.
In the winter months, Yucca plants can freeze, so they will need frost protection. Cold damage causes leaves to turn yellow first, then brown and die.
Keep in mind that Yuccas will use more water in high heat so be sure that the plant isn’t thirsty for too long, but be extra vigilant that it isn’t overwatered either, as that’s where the real threat is – over-watering.
7 – Transplant Shock
As Yucca plants can grow big, they may need cut to manage its height. When pruning aggressively, the plant can go into a state of shock.
To manage the height of these plants, you can cut a Yucca and replant it, gift it to someone, or sell the cutting on a marketplace. The trunk can be severed, the plant divided and then repotted. Naturally, such drastic pruning is going to stress the plant and the result of that is yellowing leaves.
It may be unavoidable, but it can be better managed. If you find your plant is growing intrusively large and need to cut it down, do so at the beginning of spring season as that’s when there’s more light, yet not extremely high temperatures.
The higher levels of sunlight contribute to its healing, and gets the propagated plant off to a better start because it acclimates faster to the soil medium.
Best practice for Yucca propagation is to cut it down in the spring, repot in a suitably sized container (slightly wider than the root ball), using the same soil mix as the parent plant.
Prior to putting it into the pot though, leave the cut trunks in open-air exposed to natural light for two to three hours to dry out, then put them in the new pots.
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.