Yaupon holly (Ilex vomitoria) is a great addition to any property. It’s a striking green – similar to Japanese holly, but with a much better display of berries. A US native, it’s particularly popular in the southern states, managing the heat much better than its Japanese cousin.
It’s often sold as a ‘hassle-free’ plant – but it isn’t without its problems. You need to know a little to successfully get it established and manage the main issues…
Yaupon hollies can grow poorly or turn brown or yellow if they are not given enough water, particularly when young. They grow poorly in alkaline soil, in which the roots struggle to take up iron, and are susceptible to fungal infections botryosphaeria canker and black root rot.
I know a LOT about hollies and would love to fill you in on the info on this shrub. I always draw on my own experience and enhance it with reliable, scientific research (my wife will tell you I spend a lot of time researching in huge old plant and tree books!) so you know you can trust what you read.
Ilex vomitoria is so delightfully named because of the now debunked belief that it was ingested in order to induce vomiting in Native American ceremonies. But its leaves do contain caffeine and make a great alternative to morning coffee – scroll down for more info.
My yaupon holly has yellow leaves
Yaupon is an evergreen tree, but the word can be a bit misleading.
It’s normal for a few of the leaves on a yaupon holly to turn yellow each year. This typically happens around spring or early summer to older leaves, around the base or inner part of the shrub. Eventually, these yellow leaves will fall off.
But there are numerous other things that will make the leaves go yellow in holly species. So how do you know if you have a problem?
- A lot of the leaves are yellow (it should be well under a third each year)
- Outer (new) leaves are yellow
- It’s happening out of season (i.e not in spring or early summer)
Causes of yellow leaves on yaupon holly
Yaupon hollies most often are stressed because of lack of water, too much water, or because its soil is the wrong pH. The other major cause is recent planting, known as transplant shock. More on these below.
2. Iron deficiency
Holly trees and shrubs have a particular tendency to turn level when the soil doesn’t have enough iron in it. This is closely related to the ph level (how acidic or alkaline it is). Chlorosis is the term for leaves that are yellow because they lack the green pigment chlorophyll, which hollies need iron to make.
When the soil pH is more acidic (4.5 to 7), it’s easier for the roots to access iron in the soil. When it’s higher (above 7) it can have a hard time doing so and the shrub may be helped by either modifying the soil pH or adding iron to the soil.
You can reduce the soil pH (make it more acidic) by adding elemental sulfur OR add chelated iron to improve the iron content.
The perfect product that’ll do both of these things is Dr. Iron, which contains BOTH iron and sulfur (as iron sulfate). Click below (affiliate link).
Do you know your soil pH? Gardening’s a lot easier when you know you’ve got the right plants for your soil, so a pH tester’s essential kit. Personally, I use the Rapitest meter for quick checks – it uses the proper ‘logarithmic scale’ unlike many others. No batteries required. For detailed analysis including a nutrient breakdown, I use the manual kit. Click the links to check the price on Amazon.
My yaupon holly has brown leaves
Drought and brown leaves
The most common reason for yaupon hollies turning brown is that they aren’t getting enough water.
While yaupon hollies are often called ‘drought tolerant’, this really refers to shrubs that are already established – not recently planted or young ones! During this stage, it’s extremely important that you provide them with regular watering.
The browning leaves of a drought-stricken yaupon holly are usually seen in late summer or autumn, and affect the new (outermost) foliage in a symmetrical distribution.
As a general rule, you should water a yaupon holly every week during the summer, and then monthly during the cooler months, for the first few years.
Yes, that includes winter – for reasons I’ll now explain.
Windburn causing brown foliage
Yaupon holly is susceptible to windburn – meaning, particularly in winter, the leaves are dried out by strong winds, particularly when temperatures are low (and especially if it gets close to freezing).
This is a common phenomenon in evergreen shrubs, sometimes called winter desiccation or winter injury. Deciduous trees shed their leaves in winter and thus are protected from moisture loss.
Clues that your yaupon holly is experiencing windburn:
- The browning is usually asymmetrical – the wind-exposed side of the plant being the worst affected
- New foliage – out at the branch tips – is brown
- It’s typically seen in late winter or early spring
Preventing and managing brown foliage
If you’re seeing brown foliage on yaupon holly, it’s a warning about the tree’s health. I’ve found that a little bit of action here will make the shrub recover quite easily though, and improve the growth rate a lot, too:
1. Watering yaupon holly
The oft-quoted rule of thumb of 10 gallons per inch of trunk diameter will stand up well here. If using a hose, you’ll get around 10 gallons a minute minimum.
Do this weekly in the summer and monthly during the cooler months, including during the winter. This is especially important for younger yaupons.
If you have a hedge of yaupons, the best thing by far is to get a soaker (porous) hose with timer. This means you lie the hose along the length of the hedge (discretely under the mulch) all the time turn it on for 15 or 20 minutes a day. This kind of hose leaks water out along its whole length. It’s great if you want to go away for a few days. In my opinion, well worth it and the most surefire way to get your holly to thrive for years to come.
2. Adequate mulching
Why bother? It’s one of the simplest, easiest and most important things you can do to improve the health of your yaupon holly and help to keep the foliage that pleasing green color.
It does this by:
- Helping any water percolate into the soil, rather than run off
- Preventing water loss by evaporation
- Insulating the roots against temperature changes
- Slowly decomposing, acting as a natural slow-release fertilizer
- Suppressing growth of weeds and grass, which compete with the holly for moisture (and usually win)
How much mulch should you apply? Spread it evenly over the whole root area – for an individual shrub, this is usually a circle of about 3 feet in diameter. It should be 3-4 inches thick, but try to prevent it from touching the trunk of the holly, as it can contribute to rot if piled up against it.
If your hollies are currently surrounded by grass, you could carefully scrape the grass off first, or just throw the mulch on top – if it’s a thick layer, it’ll kill the grass underneath it.
The best sort in my opinion is organic mulch (bark chippings are easiest and look good). Here’s the right kind of product on Amazon (affiliate link). If you haven’t got any mulch down, or the mulch has got thin, buy some and throw it down asap!
3. Spray on anti-desiccant
Wilt stop is the number one product here (check price on Amazon) – spraying this over your leaves reduces transpiration loss in strong winds, so your foliage stays green. Pretty convenient option.
My yaupon holly is dropping leaves
Under severe stress, yaupon hollies will exhibit excessive yellowing of their leaves – which eventually drop off. This most often happens to young yaupon hollies in the first year or two after planting, and in this situation is called transplant shock.
Being moved from one location to another (or from a container into the ground) is stressful for hollies.
Yaupon holly transplants fairly well, but it’s not unusual for them to die within the first year.
It’s all to do with the roots, which, flung into a new environment, temporarily struggle to take up much water until they adjust to the new soil’s composition, nutrient content and pH.
Yaupon hollies thrive best when planting between late autumn and early spring, so the roots get a chance to adjust before the summer growing season, but unfortunately many gardeners (and landscapers) plant them during the summer when the soil is driest and the roots struggle all the more.
Your yaupon holly can make it through transplant shock if you water it frequently, which compensates for the roots’ struggles. Once again, applying a decent mulch over the roots is so important to keep the moisture in the soil (see above), and a soaker hose and timer (links to see these products on Amazon) will take all the work out of it for you.
Diseases and pests affecting yaupon holly
There are 2 diseases that you really should know about if you have a sick-looking yaupon holly, or are planning to plant them. Thankfully, yaupon holly have relative tolerance to nematode infestation, which adversely affects other holly species.
Black root rot
Black root rot affects all species of holly. Yaupon’s no exception, even though it has a bit more resistance to it than Japanese holly.
This disease is the most common infection that kills yaupon holly. It causes dieback of entire portions of the shrub, which wilt, turn yellow and lose leaves.
Thielaviopsis lives in the soil. By the time you see signs of decline above ground, the roots are completely infected.
You really need to pull the tree up and inspect the roots to diagnose this infection properly (and probably a microscope if you’re going to distinguish it from Phytophthora root rot, which also can affect hollies). So what clues are there for us everyday holly owners?
- The yaupon’s growing in waterlogged, saturated soil. Root rot is much more likely to occur in poorly drained soil, particularly clay types. Check for puddles of water under your holly.
- The yellowing affects a large portion of the shrub at a time
- It’s accompanied by leaf loss, stunted growth and wilting
- If you have other yaupon hollies, you’ll notice one or two declining while others appear healthy
Unfortunately, once root rot has taken hold, the plant usually needs to be removed. This short informative video refers to black root rot in Japanese holly (which is particularly susceptible) but all the principles apply to yaupon as well.
Often known as ‘bot canker’ for short, this is a fungus that causes the leaves on entire branches to turn yellow at the same time. Those leaves will eventually drop off.
Cankers are oozing raised or sunken wounds that the infection forms in the bark – which interrupt the flow of water along that branch, causing the death of leaves that are further along.
If you see any branches dying, closely inspect the bark along that branch looking for cankers.
If the infection moves down to the trunk it’s more serious, as cankers here can ‘girdle’ numerous branches at once.
Fungicides don’t work very well, so you’ve got to use ‘cultural control’ – i.e. prune off any infected branches to limit spread of the infection towards the trunk.
Make sure you:
- Leave a couple of inches of healthy tissue between your cut and the canker
- Clean your pruners between cuts to avoid spreading the infection (use rubbing alcohol, or 70% alcohol hand sanitizer)
- Lift any pruned branches and dispose of them in the trash
Spots on yaupon holly leaves
There are no serious diseases of yaupon that cause leaf spotting. ‘Holly leaf miner’ is a well known cosmetic issue in many species of holly (it’s caused by a tiny larva burrowing through the leaf tissue), but it’s actually uncommon in yaupon holly.
If you see spots on yaupon holly leaves that are already yellow, this is common – fungi infect leaves that are dying to feed off them, and the spots in themselves are of little consequence.
Could it be a soil issue?
Yaupon holly is quite tolerant to different soil types and is one of the more forgiving holly species in this regard.
The main issue is alkaline soil, which can affect iron absorption and lead to leaf yellowing (chlorosis) – see above. It’s happiest in soil with a pH or 4.5-6.5 (scroll to ‘iron deficiency’ above for info about testing your soil’s ph).
Yaupons growing in clay soil are more likely to be troubled by black root rot.
Will fertilizer help yaupon holly?
Yes – fertilizing your yaupon holly helps to reduce stress and the discolored foliage that comes with it. Nutrient-starved yaupons are more likely to pick up infections as well.
Applying a slow-release fertilizer is an easy win. Here’s the one I use, which which I’ve had good results. ‘Complete’ fertilizers contain the three most important components – nitrogen, potassium and phosphate. Check the price on Amazon (affiliate link).
Yaupon holly and sunlight requirements
Where do these plants grow best on your property?
Yaupon holly does grow pretty reliably in the shade – one of the things that makes it a useful hedging plant. But it grows faster and more vigorously if it’s in direct sunlight for at least part of the day, or in a fully sun-exposed spot.
Yaupon holly has no berries
Hollies are dioecious – each shrub or tree is either male or female. But even female yaupons take time to reach maturity and start producing.
When purchasing yaupons, check with the nursery to make sure you plant both males and females – that way you should get an abundant display year after year.
How to make cassina (yaupon holly tea)
Finally, if you have a yaupon holly, you’ve got to try this. Lots of caffeine to get you started in the morning. My wife thinks I drink too much caffeine as it is, so isn’t too keen on me hacking up the hedge…
Krzysztof Ziarnek, Kenraiz, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
David J. Stang, CC BY-SA 4.0 https://creativecommons.org/licenses/by-sa/4.0, via Wikimedia Commons
Forest and Kim Starr, CC BY 2.0 https://creativecommons.org/licenses/by/2.0, via Wikimedia Commons