Rosemary can easily be grown in large pots or containers. This means that you can bring your plant indoors during the winter or place it inside your greenhouse if you have one. It also allows you to move your rosemary around so that it gets all the sun that it needs.
Here’s the complete guide to growing rosemary in pots successfully.
Choose The Pot Carefully
As rosemary is quite a vigorous grower during spring and summer, you want to ensure that you choose a pot that is large enough to accommodate all of this growth. Otherwise, you’ll have to repot your plant more often than is necessary.
Your pot should be at least 12 inches (30 cm) in diameter. This will give your plant enough room to grow to maturity and beyond. You also want to ensure that the pot is at least 6 to 8 inches (15 to 20 cm) deep to accommodate the plant’s root system adequately.
However, if you plan on growing your rosemary indoors on a bright windowsill, you can start your plant in a smaller pot and limit its growth through the regular tip and root pruning. You’ll find more information on root pruning below.
Alternatively, you can start your rosemary in smaller pots indoors and then repot your plant into a larger pot once it’s outgrown the current one. Then, take some cuttings and propagate them so that you can always have small pots of rosemary growing indoors on your kitchen windowsill.
If you do this consistently, you’ll find that you have so many pots of rosemary in various sizes that you may just have to give some away to your family and friends.
Ensure that the pot you select has plenty of drainage holes. Unglazed or terracotta pots work very well for rosemary as they allow for better drainage, and the plant will love the heat that gets absorbed by these materials. However, you can also use a plastic pot if you wish.
You Can Start Your Rosemary Plant Easily From Cuttings
While it’s easy to go to your local garden center and purchase a young rosemary plant to grow in the pot that you’ve selected, it’s almost as easy to grow your own plant from cuttings.
If you have a neighbor or friend with a rosemary plant, ask them if you can take a few tip cuttings to propagate your own plants. You can either take some softwood cuttings in spring or wait until late fall or early winter and take some semi-hardwood cuttings.
- For softwood cuttings, just take the top 4 to 5 inches (10 to 12 cms) from the top of the healthiest stems. The stems should still be green but semi-firm.
- For semi-hardwood cuttings, take the same length from the top of some healthy stems that are woody but still quite flexible.
- Remove the lower leaves from these cuttings but leave a few leaves at the top.
- You can start these cuttings in a small pot, or you can even use a seedling tray.
- Fill the pot or tray with a seed-raising mix or propagating sand.
- Poke a hole in the mix using a pencil or dibbler for each cutting.
- Dip the base of each cutting into some rooting hormone. You can either use a liquid or powder rooting hormone. Some gardeners have also found success by using plain flour or even honey as a substitute for rooting hormone.
- Insert the cuttings into the holes that you’ve made and firm the soil around each one.
- Water just enough to dampen the mix and place the cuttings in a warm, bright spot out of direct sunlight. If you’re doing this in winter, it’s helpful to place a cloche or plastic bag over the pot to create some additional humidity. If you’re using a plastic bag, you can easily prop this up using some wooden skewers. Alternatively, you can cut the bottom of a soft drink bottle and place this over your cuttings to act as a cloche.
- Once the individual cuttings have produced roots, you can plant each one into its own large pot as described above.
Best Soil For Rosemary
Rosemary is a drought-tolerant plant once it’s well established, so it does require well-drained soil. This delicious, aromatic herb doesn’t respond well to wet and soggy conditions.
Therefore, you want to choose an open and friable potting mix that contains a fair amount of organic matter but allows for easy drainage when it’s being watered. You can even consider adding some perlite or builder’s sand to ensure that the mix drains well. Measure this in volume in the ratio of one part perlite or sand to two parts potting mix.
It’s also noteworthy to consider that rosemary prefers a soil that is slightly alkaline rather than an acidic soil mix. If you test the mix that you’re using and it’s a little on the acidic side, you can easily add some lime or dolomite to raise the pH level.
Does Rosemary Need Full Sun?
Rosemary thrives in hot and dry climates. However, it can also be grown in colder climates as long as it receives enough sun and the plant is protected from frost and snow.
For optimum growth, flavor, and flowering, rosemary requires at least 6 to 8 hours of sunlight on a daily basis. Being a Mediterranean plant, it just loves the sun and will thrive if given enough sunlight each and every day.
Growing your rosemary in a large pot means that you can move the pot around during the day to ensure that your perennial plant gets as much sun as possible.
Add Some Mulch To The Top Of The Soil
Because the soil in containers dries out fairly quickly, you can easily top the soil with a layer of mulch to limit the amount of evaporation. You can either just use some straw or hay or add a nice layer of decorative pebbles or stones.
Watering Rosemary In Pots
When growing your rosemary in a pot, you have to understand that the soil in the pot will dry out much faster than the soil in the ground. Therefore, monitoring soil moisture is much more important for pot-grown herbs such as rosemary.
As mentioned before, rosemary is drought-tolerant once it’s well-established, but that doesn’t mean that you should neglect to water your plant. As a general rule of thumb, you should give your plant some water when the top 1 or 2 inches of soil are dry to the touch.
You can test the soil moisture either by poking your finger into the soil to feel whether it’s damp or dry or by inserting a wooden chopstick or skewer down for around 2 inches. If the skewer comes out completely dry, it’s time to water. However, if you pull the skewer out and there’s slightly damp soil clinging to it, then you can leave the plant for another day or two.
You could also invest in a moisture meter that will give you a digital reading on the amount of moisture in the soil.
Once you’ve given your plant a good drink, be sure to allow any excess water to drain away completely. Do not let water sit in a saucer underneath the plant for any period of time.
If you want to know more about watering rosemary, I wrote an article about that.
Does Rosemary Grown In Pots Need Fertilizer?
To ensure that your rosemary plant is growing well, you should apply some liquid fertilizer from mid-spring to early fall. If you’re using a good quality liquid fertilizer, this can be applied once a week during the warmer months as long as you dilute it to half strength. Just add the fertilizer as part of your regular watering schedule.
Liquid seaweed or fish emulsion is great for this, or you could even make some compost tea if you have your own compost bin. Worm tea also works fabulously.
Try not to fertilize your rosemary in winter or early spring. While this will encourage lots of new growth, it might inhibit flowering. Most rosemary bushes look absolutely stunning when they’re in flower, and the flowers themselves are edible too. Plus, they attract plenty of pollinators to your garden.
Should You Prune Your Rosemary?
It goes without saying that every time you harvest a few sprigs from your rosemary plant, you’re actually doing a little pruning. However, if you’re not using quite enough of this lovely herb in your cooking, it’s a good idea to give your plant an all-over tip prune around once a month during the growing season.
This will help to maintain the lovely shape of your plant and avoid any straggly growth from getting out of hand. However, don’t throw away the parts that you’ve pruned off. These can easily be dried, either in a dehydrator or in a slow oven, and then put into jars to use when you need them.
Larger rosemary plants can also benefit from a root trim every couple of years. If you notice that the roots are starting to come out of the drainage holes or it’s taking a long time for the water to drain down through the soil, it’s time to give the roots a little trim.
Here’s what to do:
- Carefully take the plant out of the pot.
- Using a sharp utility knife, cut off the bottom third of the root ball. This may sound a little harsh, but it’s exactly what the plant needs when it’s become root-bound.
- You can then repot the plant into the same pot if it’s still large enough. You want to allow around one inch (2-3 cm) of free space on all sides of the root ball.
- If your rosemary plant has grown too large, you may have to plant it into a bigger pot now.
- Make sure that you use fresh potting mix for this so that the plant feels invigorated by its new environment.
Does Rosemary Have Any Pest Or Disease Problems?
Being such a lovely aromatic herb means that rosemary has very few pests or disease problems. In very humid climates, you might experience some problems with powdery mildew. However, if there’s plenty of airflow around your plant and it’s being exposed to plenty of sunshine, this shouldn’t be a problem for you.
The only other problem to watch out for is root rot. That’s precisely why your rosemary needs extremely well-draining soil and should never be allowed to sit in water.
Frequently Asked Questions
Does rosemary grow well in containers?
Rosemary grows incredibly well in a container as long as the container is large enough, the plant gets plenty of bright light, and the potting mix and container have excellent drainage.
How often should potted rosemary be watered?
You should water your potted rosemary when the top 1 or 2 inches of soil are dry. Depending on your climate, this can translate to once per week in summer and once every 2 weeks in winter.
What is the best fertilizer for rosemary?
A liquid fertilizer such as liquid seaweed or fish emulsion used at half strength is ideal for using on rosemary plants that are grown in pots.
Should you mist your rosemary plant?
Rosemary naturally grows in a Mediterranean climate, so it really shouldn’t need misting. However, if you’re growing your rosemary indoors and the air is very dry, you can safely mist your plant once a week. Alternatively, you can use a humidifier in the room that will provide benefits to both you and your plants.
What causes rosemary leaves to turn yellow?
Yellowing leaves are usually due to overwatering or poor drainage of the potting mix. It could also mean that you’ve been overfertilizing your plant.
Can you grow rosemary in partial shade?
It is possible to grow rosemary in partial shade as long as it gets a minimum of 6 hours of sunlight daily. This plant will generally not thrive if grown in full shade and will eventually die when starved of direct sunlight.