I love to grow oregano, a low-maintenance perennial herb that keeps growing and gives me a fresh supply of flavourful herbs for my pizza toppings!
I had a little bit of trouble when I first started growing it (it looked like it was dying) because I assumed it had the exact same care requirements as my lavender and rosemary. However, there are some specific nuances you need to know to grow oregano successfully to keep it healthy and prevent it from dying.
In my job at a garden center, I am frequently tasked with reviving dying herbs such as oregano. I’ve experimented with different methods of revival to determine what actually works. In this article, I’ll share all the tips and secrets I’ve learned in a step-by-step guide so you can revive your dying plant.
Let’s remember that Oregano is a low-maintenance Mediterranean herb that can live for around 10 years in the right conditions.
For us to grow oregano successfully, we need to replicate some of the growing conditions of the Mediterranean, which include full sun, well-draining soil (amended with sand or grit), and allowing the soil to dry out between bouts of watering.
So why is your oregano dying?
Dying oregano is often caused by damp soil due to over-watering or slow-draining soil, which causes root rot. Oregano requires well-draining soil and infrequent watering to thrive. Fungal pathogens thrive in damp soil which turns oregano leaves brown, black, or yellow and result in dying oregano.
We also need to be are that oregano can also suffer if grown in the wrong type of pot or container and because of fertilizer high in nitrogen or because of a lack of sun.
Keep reading for all my best tips and how to recreate the growing conditions of the oregano’s native Mediterranean environment in your garden and revive your dying oregano…
Is Your Oregano Turning Brown, Black or Yellow? (Fungal Disease)
- Symptoms. The oregano plant is wilting or drooping, and the leaves are turning brown, black, or yellow.
- Causes. Fungal disease and root rot as a result of overwatering, slow-draining soils, and high rainfall.
As we discussed, Oregano is native to the Mediterranean region of Europe, where it grows in full sun, sandy soil with infrequent rainfall.
We need to think in terms of how oregano has specifically adapted to thrive in these arid conditions with dry soil. Plants tend to suffer from too much moisture, which, in my experience, is the most common reason people come to me to tell me their plants are dying.
However, overwatering isn’t the only culprit! I’ve seen how slow-draining soils, high rainfall, and high humidity can all cause the oregano to turn brown or black with a drooping or wilting appearance, as damp conditions promote fungal diseases such as root rot.
From my research, there are several pathogens of fungal disease that can turn oregano leaves (and other Mediterranean plants) brown or black, and they all thrive in damp soils, which is the opposite of the oregano’s preferred soil conditions.
How to Revive Your Oregano if it is Turning Brown or Black
- If your oregano is showing signs of stress due to root rot and fungal disease (drooping and turning brown), I recommend scaling back the watering of the plant and sheltering it from rainfall.
- Carefully lift your oregano out of the ground (I always advise easing the plant out with a fork rather the a spade to protect the roots) and inspect the roots. Are the roots soft and brown with a rotten look and a bad smell? If so, snip them off with a pair of pruners. You always need to sterilize the pruners with alcohol disinfectant after each cut to prevent the spread of the fungus from infected roots to otherwise healthy roots.
- Snip off any branches with brown or black leaves and burn or throw them away. I must caution you against putting them on a compost heap, as they are host to fungus that could stay dormant in your garden compost.
- Replant your oregano plant in a pot in a pot with new compost and add around 30% sand to the volume of the pot to improve drainage to help the roots stay dry and recover.
When you have transplanted the oregano into new soil in a pot, I personally refrain from watering for at least two weeks and shield the pot from excessive rainfall.
I personally love to grow oregano in pots and containers as they have favorable drainage conditions, and it is far easier to amend the soil to suit the oregano than when planting in garden soil.
In fact, if you don’t live in a Mediterranean climate, I would recommend you grow oregano in pots to prevent them from dying from root rot.
I have tested several different ways of revving oregano to see which is most effective, and I have experienced many different potting mediums and different compositions of potting mixes over the years of potting up and growing Mediterranean herbs.
What I’ve found works best for growing oregano is to amend the potting soil with 30% horticultural sand (by volume of the pot).
Grit works well, too, but from my years of experience, I’ve just found that sand works better, which is probably because it is slightly closer to the oregano’s natural soil composition.
By adding horticultural sand or grit, you can help replicate the sandy soil conditions of the Mediterranean, where oregano thrives in its native environment.
The sand helps to improve soil drainage, allowing the soil to dry out quickly between bouts of watering or high rainfall. This reduces the risk of root rot and fungal disease.
The next stage of revival is to always locate oregano in a sunny location as it naturally grows in open areas with full sun. Increased sunlight helps ensure the soil and any moisture around the foliage can dry out which helps to mitigate humid conditions.
I personally have my oregano in full sun, which not only helps it revive but also increases the concentration of essential oils in the leaves which increases the aroma and flavor for taste!
I find it helpful to locate my potted oregano in an area with good airflow and allow for some distance between the pots so that there isn’t an overly humid microclimate.
If you follow these steps, the oregano should show signs of recovery in about 3 weeks; however, from experience, severely affected oregano where all the leaves are discolored can be difficult to save, in which case I recommend burning the plant or throwing it away so that the fungus disease does not spread to other herbs in your garden.
Why Are My Oregano Leaves Turning Yellow?
- Symptoms. Yellow leaves with leggy growth, weak aroma, and poor culinary taste of the leaves.
- Causes. Soil that is high in nitrogen as a result of using fertilizer, damp soil, or because the pot or container is too small, with a deficit of nutrients for growing oregano.
Why is your oregano turning yellow? In my experience and from my research, oregano can turn yellow because of:
- Excess Nitrogen in the soil because of fertilizer or high nitrogen soil amendments.
- Overwatering, slow-draining soil, or high rainfall causes soil moisture, which results in fungal disease, which causes leaves to turn yellow as a sign of stress.
- Pot-bound roots can cause yellow oregano leaves.
So I always think it’s important to appreciate how oregano grows in its natural habitat so we can understand how to replicate these conditions in order to help revive it (or prevent it from dying in the first place)…
Oregano is a Mediterranean herb that grows well in low to medium nutrient soils with a high sand or gravel content.
If the soil is too rich in nutrients or because of fertilizer, there can be too much nitrogen in the soil, which causes yellow leaves, lots of foliage growth with weak drooping stems, a weaker aroma, and a different culinary taste.
To be honest, this is the most common reason I see for people’s oregano turning yellow. I think some people use fertilizer on other herbs, such as cilantro and parsley, which do prefer more nutrients, and they don’t know oregano prefers lower nutrients, which I acknowledge does seem rather counterintuitive.
However, I should also point out that oregano leaves can also turn yellow as a sign of stress due to overwatering.
I know we covered oregano turning brown and black due to overwatering, but what I find happens is that if the oregano is slightly overwatering or perhaps the soil drains slightly too slowly, then the leaves start to turn yellow, whereas if they are severely overwatered, the leaves turn brown and black.
In my experience, potted and container oregano requires a good soak around once per week but the soil should have a chance to dry out between bouts of watering.
As we discussed, if the soil is consistently moist, then this can cause fungal disease, which can result in leaves turning yellow or even brown and black.
How to Revive Oregano with Yellow Leaves
The secret here is again to revive oregano with yellow leaves is to replicate the soil conditions of the Mediterranean to which the oregano has adapted to growing.
As I’ve discussed, to prevent fungal diseases associated with overwatering and damp, slow-draining soil, it is important to add sand or grit to the potting mix or planting area when planting your oregano.
Sand and grit significantly improve soil drainage and help to emulate the natural conditions in which oregano grows and thrives.
However, I have a great tip for those of you struggling with overwatering…
Pro Tip: Plant your oregano in clay or terracotta pots. They are porous, which allows the potting soil to dry out more evenly, helping to mitigate root rot due to overwatering. I find this is also very helpful for preventing root rot for those of us who grow oregano in a higher rainfall climate.
So I had someone who had added too much fertilizer to other potted oregano ask me for help (I work at a garden center and regularly have to revive plants!) The oregano was yellow, drooping growth with a poor culinary taste and a weaker smell. I cut back the oregano (with my sharp pruners) by 1/2 (this was in late Spring), and the plant grew back and started to regrow the same year with leaves that had a stronger, more pungent aroma, and the plant looked healthier.
The following year the growth was even better.
I typically wouldn’t cut back any more than 1/2 the length of the growth at any one time, as you can shock the plant if you cut it back too much!
I should note that oregano is more resilient and can tolerate a good cut back, more so than other Mediterranean plants such as lavender.
Cutting your oregano back stimulates new green growth from the oregano that should have a better flavor and aroma. I would discard any yellow leaves as they have a poor flavor.
For a great visual guide to pruning oregano, watch this YouTube video:
While this is rare, I have seen when oregano turns yellow due to suffering from a nutrient deficit due to a small pot, or perhaps it has been in the same pot for many years, and the roots have exhausted the available nutrients.
In this case, I typically repot the oregano in a larger pot with new compost.
The ideal pot for oregano should be at least 12 inches across, with enough soil and nutrients for the plant to establish roots and thrive.
Ensure the pot has drainage holes in the base. If the oregano has been growing in a small pot, it could benefit from pruning to stimulate new green growth. The leaves of the oregano should show signs of recovery over the next few weeks.
Why is My Potted Oregano Dying?
As I just mentioned, in my experience, if your oregano is dying in a pot, this is often because the pot is too small or there are not enough drainage holes in the base of the pot. This prevents excess water from escaping and causes your oregano to die from root rot.
The ideal pot for growing oregano should be:
- At least 12 inches across so there is enough room for root growth and insulation from the cold.
- A pot should have several drainage holes in the base so excess water can escape to recreate the relatively dry soil conditions that oregano prefers.
Remember we talked about oregano being native to the Mediterranean, where the Winter temperatures are mild?
From my research, the roots of a plant are the most cold sensitive part of the plant. What I’ve personally seen happen in cold climates is that oregano can die over Winter when in a pot because the roots are pot bound against the side of the pot causing the roots to freeze and the plant to die.
Success Tip: I’ve personally noticed that oregano is more likely to die in a pot over Winter if the pot is thinner and made of plastic as opposed to a pot that’s thicker and made with ceramic. If you live in a cold climate that regularly experiences freezing temperatures then I urge you to pot up your oregano in a nice big pot with a thicker rim.
Okay, so we talked about the thickness of the pot making a difference, but what about the size? A larger pot has more capacity for soil which helps insulate the roots of your oregano against the cold temperatures.
Larger pots also provide more space for the roots to establish a healthy plant.
Of course, we need to talk about drainage. As oregano is so sensitive to overwatering, good drainage in the base of the pot is essential. I would avoid using a tray or saucer underneath the pot, as this can prevent water from draining and cause root rot.
Important Tip: To ensure good drainage, you can elevate the pot off the ground on a stand or ‘feet’ so that water does not collect underneath the drainage holes and cause root rot.
Replant your oregano in an appropriately sized pot with good drainage and in multi-purpose compost amended with sand to improve the drainage.
If the oregano is showing signs of root rot (brown or black leaves and dark brown, rotten roots) then snip off the infected parts of the plant back to healthy growth (follow the instructions about root rot written above).
Why is My Oregano Not Growing or With Spindly Growth? (Oregano Prefer Full Sun)
Were you expecting an incredible abundance of flavorsome oregano leaves only to be greeted by a sluggish growth rate? This is a common complaint! From my observations, if your oregano is not growing, it is usually due to a lack of sun.
Again, let’s consider Orgeano’s natural environment in the Mediterranean, where it grows in full sun.
If your plant is in partial shade or dappled light, then the oregano does not have the energy and resources to grow properly, and the aroma from the aroma of the leaves won’t be as strong or taste as flavourful.
The only way to remedy this is to transplant your oregano (or simply move it if it is in a pot or container) to a sunnier location with at least 6 hours of sun.
When I moved my oregano to a sunnier spot, the aroma from the leaves was noticeably more pronounced than before, and my homemade pizza tasted delicious!
I’ve personally observed that oregano benefits from an open and sunny location even during their Winter dormancy, with more sun in Winter giving it a head start on the growing season in Spring.
If you move the oregano to an area of full sun with good airflow and well-draining soil (amended with sand or grit), then your oregano should start to recover, and the aroma should be more pronounced.
Do you have any questions or insights you’d like to share about your oregano? Please leave a comment below, and I’ll reply to you!! I love hearing from you and hearing the different perspectives of other gardeners!
Key Takeaways:
- The reasons for oregano dying are because the soil is too damp due to overwatering or slow draining soil, a lack of sun, because of too much nitrogen in the soil, or because your pot or container is too small for growing oregano.
- To revive oregano and prevent fungal disease it is important to recreate the growing conditions of the Mediterranean with full sun, well-draining sandy soils, and only watering pots once per week during Spring and Summer.
- Oregano with black or brown leaves is likely to suffer from root rot or a fungal disease. Snip off the infected growth with sterile pruners (wipe the blades after each cut to prevent spreading fungus) and replant the oregano in a pot with new compost amended with sand or grit to improve the drainage and locate it in full sun.
- Plant oregano in large pots to protect against the cold, prevent the root from becoming pot-bound, and ensure there are drainage holes in the base of the pot for excess water to escape.