I love rosemary and grow about 10 different rosemary plants in all different kinds of pots (I propagate a lot of rosemary, so I always have loads of plants!)
I have learned through some trial and error that the type of the pot and size of the pot is very important to grow rosemary successfully.
Here, in this post, I share with you all the tips and secrets I have learned…
Clay and terracotta pots measuring at least 12 inches across are the best pots for growing rosemary. Clay and terracotta are porous, which allows the soil to dry after watering; they do not heat up as quickly in the sun compared to plastic or metal pots and provide more protection from frost in Winter.
Rosemary is a Mediterranean herb that has adapted to resist drought and prefers the soil to dry out somewhat between bouts of watering.
Keep reading to learn which pots and containers are the best for growing rosemary and how to avoid the most common mistakes when growing potted rosemary…
Best Pot Size for Growing Rosemary
Rosemary can come in a variety of sizes, with some varieties growing as much as 2 or 3 feet across (such as ‘Tuscan blue’), whereas some varieties stay much more compact with annual pruning.
However, I recommend that you plant your rosemary in a pot that is at least 12 inches wide with the same proportional depth, even if you have a smaller variety of rosemary or if the rosemary is at an immature stage of growth.
It is important to plant rosemary in a pot or container that is at least 12 inches because the pot needs to have enough capacity to hold enough soil for the rosemary’s roots to stay insulated in the Winter and so that the pot does not dry out too quickly in the blazing sunshine in the middle of Summer.
A 12-inch pot also has enough room for the rosemary’s roots to develop so it can access the moisture and nutrients it requires to grow and stay healthy.
- I must emphasize the importance of the 12 inches depth of the pot. Here’s why…
When I first started growing rosemary, my own rosemary was planted in a nice wide pot, but it wasn’t particularly deep. I noticed my rosemary had stunted growth and hadn’t grown much for nearly 2 years. It also didn’t look as healthy as it should.
I learned that rosemary has surprisingly deep roots, even as smaller plants. My rosemary’s roots had reached the bottom of the relatively shallow pot, which caused it to stop growing.
When I transferred my rosemary to a deeper pot, it resumed growing and still looks glorious to this day!
Rosemary of all types grow very well in pots, and pots have more favorable drainage conditions compared with garden borders and flower beds, which is important because rosemary are Mediterranean plants that are adapted to well-draining conditions, which helps to avoid root rot.
As rosemary is a Mediterranean plant, it grows, smells, tastes, and flowers the best when it is full sun.
However, we should remember that full sun can drastically increase the rate at which pots dry out on the hottest days, which is why having a larger pot with a good capacity for soil is so important, as smaller pots than 12 inches can dry out so quickly that the rosemary roots do not have enough chance to draw up the moisture they need.
It is also worth considering that pots essentially raise the rosemary’s root system above ground, which can expose the roots to cold temperatures in Winter. I now live in a cold climate that goes below freezing in Winter.
People in my area have accidentally killed their rosemary by planting it in pots that are too small…
From my research, I discovered that rosemary roots are the most cold-sensitive part of the plant. Ordinarily, the surrounding soil acts as insulation from the cold to maintain a temperature during Winter that the roots can tolerate.
If the pot is too small, then it does not contain enough soil to properly insulate the roots from the worst of the cold, which can cause your rosemary to die back in Winter.
A larger pot has enough soil to insulate the roots and protect them from frost in climates with colder Winters so that they survive and flower well the following year.
(Read my article, best soil for rosemary in pots).
Best Material Rosemary Pots
Rosemary are hardy plants when they are established and growing in the right conditions, and they can grow in pots made from any material, but some types of pots are more favorable for growing rosemary than others.
I did an Experiment to See Which Pots are Best for Rosemary…
From my own testing, I can tell you that I have personally grown rosemary plants in metal, plastic, clay, terracotta, and ceramic-style pots.
I had so many rosemary plants (because I propagate them every year, which I recommend you do because it is so easy!) that I decided to do a little experiment!
I grew rosemary in every type of pot I could find (as I mentioned, metal, plastic, clay, terracotta, and ceramic). To keep things fair, I made sure every pot was 12 inches across and 12 inches deep. I also used the same potting medium of 70% potting soil to 30% horticultural grit to keep things fair.
Keep in mind that I was living in the Pacific Northwest USA at the time, which has relatively high rainfall.
I planted my rosemary in their respective pots at the start of spring in March and monitored how each rosemary plant faired throughout the year. In particular, I was interested in how often each pot needed watering (as watering and problems with overwatering are the most common reasons people struggle to grow rosemary).
My initial hypothesis was that the rosemary would grow better in the clay, terracotta, and unglazed ceramic pots as they are porous, which allows the soil to dry out more evenly.
The Results! Which Pot was Best?
By the end of the Summer, my rosemary in the porous clay pots grew more by about an inch to each stem, and I actually thought they had a slightly stronger fragrance compared to the rosemary that grew in the plastic pots.
Rosemary in the terracotta and ceramic pots also grew well. What I noticed is that the soil in the porous pots (clay in particular) dried out more quickly after rainfall, which I see as an advantage when growing rosemary as it recreates the well-draining dry soil conditions of the rosemary’s native environment and reduces the risk of root rot.
I also discovered something quite interesting that I hadn’t really considered before the experiment started. The ceramic, clay, and terracotta pots were much thicker than the tin, plastic, and metal pots, which meant the soil did not heat up as much.
The soil in the plastic pot on a very hot day would heat up so quickly in the sun that the soil was bone dry by the end of the day, and even the drought-resistant rosemary began to wilt slightly as a sign of stress (and needed watering more often). I think this is the reason why the rosemary in the plastic pot did not grow as much as the others.
The metal pot was also impermeable (as is plastic, of course), and I noticed the soil stayed perhaps uncomfortably damp for longer after rainfall.
The rosemary in the metal pot was affected by the soil heating up in the sun too much, just like the plastic pot, and damp soil after rainfall, which caused the leaves to wilt even after watering, which is a sign of root rot, so I had to reduce how often I watered the rosemary in the metal pot to stop it from dying.
My Verdict!
Whether you live in a hot and dry or cool and rainy climate, my personal recommendation is that ceramic, clay, and terracotta pots are all great options. The clay pots are, in my opinion, the best option due to their porous, breathable structure and ability to survive winter (my terracotta pot broke in winter due to weathering).
The porous nature of these pots allowed the soil to dry out nicely and gradually, and the rosemary thrived.
I also noticed that in Winter, the thicker pots insulated the rosemary’s cold-sensitive roots more effectively, which ensured they survived despite a cold climate.
The rosemary in the thin metal pot actually died in the Winter, which I attribute to the cold, although the higher winter rainfall also probably played a part from my research and personal experience, root rot is the most common problem when growing rosemary).
One thing I would say in favor of the plastic pots is that they were much lighter, so if you had to move your rosemary pots around a lot, say if you are reorganizing your patio or bringing your rosemary to a more shelter spot in Winter as some rosemary varieties are not cold hardy the plastic could be a good option.
For more information, read my articles:
Good Drainage is Key for Rosemary Pots and Containers
Whichever style of pot or container you choose for your rosemary the most important feature is that it has to have drainage holes in the base to allow excess water to escape after watering.
If the pot does not have drainage holes, then water collects in the bottom, and the soil around the root of the rosemary plant becomes saturated, which promotes the conditions for root rot, causing the rosemary to turn yellow, brown, or black and die back.
(Read my article, how to revive a dying rosemary plant).
It is important to emphasize that drainage holes should also be kept clear to allow water to escape easily away from the roots.
Soil can become compacted in pots over time, so the best way to ensure that the drainage holes stay clear is to use a 1-inch layer of gravel on the bottom of the pot before potting soil.
The gravel maintains a porous, aerated structure at the base of the pot to allow water to drain away easily, as soil compacted at the base can cause the water to drain slowly and cause boggy conditions.
Avoid this Common Mistake!
A classic mistake I see when people have potted rosemary is that they choose the right type of pot without good drainage in the base but place the pot on a tray to prevent water from spilling on their patio of watering the rosemary.
Rosemary originates in the Mediterranean region of Europe and requires dryer soil conditions than most plants. If the pot is on a tray with water around the base, it is contrary to rosemary’s preferred conditions and can cause root rot.
Pro tip: If, like me, you live in a climate of high rainfall, then I recommend using ‘feet’ under your rosemary pots to elevate them off the ground slightly which ensures good drainage and prevents watering pooling around the base of the pot. I learned the hard way when I had one rosemary die because water drained out the pot but was trapped on the patio slab underneath, which caused damp conditions and root rot!
Read my article, How to Propagate Rosemary from Cuttings.
Key Takeaways:
- Clay and terracotta pots are the best pots for growing rosemary. Clay and terracotta pots are more breathable than plastic and metal pots allowing the soil to dry out more efficiently, they do not heat up too quickly in the sun and resist frost damaging the rosemary’s roots in Winter.
- Clay and terracotta pots that measure 12 inches across can hold enough soil for the rosemary root system to develop and provide enough insulation to protect the rosemary roots from the cold.
- Always plant rosemary in pots with drainage holes in the base to allow excess water to drain away from the roots and prevent root rot.
- Avoid placing your rosemary on a tray as this collects water, and the soil stays boggy, causing root rot. Placing your pot on stands is best practice to allow for good drainage and prevent root rot.