15 Tips for Growing Rosemary in Pots or Containers
Growing rosemary in pots or containers isn't difficult. In fact, rosemary is one of the easiest plants to grow in containers. But how well it grows will depend on a few different factors. In this article, gardening expert and former organic farmer Logan Hailey shares her top tips for growing beautiful rosemary plants in containers or pots this season.
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If you’re not lucky enough to live in a Mediterranean climate, you can still grow fragrant rosemary plants in a pot. Gardeners in zones 8 and cooler may have trouble growing rosemary outdoors due to colder winters.
Container rosemary gives you more flexibility for moving rosemary with the seasons and maintaining a perennial herb bush without worrying about cold weather.
No matter what type of container you are growing in, rosemary can thrive if given proper attention. While it prefers larger containers, it can do just fine in terra cotta pots, ceramic containers, and even fabric containers. Here are my top tips for growing amazing rosemary plants in your container garden this season!
First, it’s All About the Soil
The quickest way to stunt or kill a potted rosemary plant is by planting it in heavy, poorly drained soil. Before you even plant your rosemary, make sure that you choose the best-drained soil mix possible. Avoid regular potting mixes or anything designed for vegetables. Instead, look for:
- Gritty, sandy, or pea gravel mixtures
- Cactus soil blends
- Seed starter mix with vermiculite or perlite
- Coco coir and peat moss
Like all Mediterranean herbs, rosemary is adapted to the fast-draining gravelly soil of the slopes along the Mediterranean Sea.
This aromatic perennial absolutely demands soil that filters water through as fast as possible. This is especially important in a pot because the plant’s root zone is limited to the size of the container.
A dry, porous soil mix ensures that irrigation flows rapidly through the rosemary roots and out of the bottom of the container.
The plant will never sit in soggy soil, which means you won’t need to worry about root rot or other diseases! Better yet, proper drainage will keep your potted rosemary plant more fragrant, green, and fast-growing.
Our favorite time-tested soil blend for rosemary is:
- 1 part perlite or pumice
- 2 parts horticultural sand
- 1 part compost or potting soil
You can also add larger gravel or rocks at the bottom of the pot to mimic the limestone bedrock of rosemary’s native habitat.
Pick a Dwarf Variety
It may seem like all rosemary is identical, but there are actually hundreds of different varieties from around the globe! Different cultivars of rosemary range from rambling vines to attractive bluish foliage to cold-hardy stout shrubs. All of them are edible, but some are more aromatic and better suited for cooking.
In its native environment, rosemary naturally grows into a massive shrub. So if you want to keep this herb contained, it’s best to choose a dwarf variety that has been bred specifically for growing in a pot. When combined with a regular pruning schedule, the right rosemary variety can stay healthy while remaining small.
Compact Varieties
‘Blue Boy’
This is the smallest rosemary variety on the market, growing to about 2 feet tall and wide at maturity (depending on pruning). The pretty flowers look like little pale blue flowers. It is slow growing yet very successful in containers. Keep in mind that it has very small needles, so you may need to harvest extra sprigs for use in recipes.
‘Golden Rain’
The golden-hued foliage of this rosemary is beautiful and attractive. It is a smaller type that doesn’t mind the lower light of a windowsill.
‘Dancing Waters’
This unique compact rosemary has some erratic growth but beautiful ¾ inch long leaves and blue-violet flowers.
‘Herb Cottage’
This handsome rosemary grows slender and upright, perfect for a medium to large pot.
Technically any rosemary variety can be grown in a container, but dwarf varieties won’t require as intensive pruning or up-potting.
Let the Soil Dry Out
Just like pothos plants or cacti, rosemary likes its soil to dry out between waterings. You should never provide potted rosemary with continuous moisture. Instead, stick your finger in the soil and check that the upper 2-4 inches are mostly dry before you give the plant a drink.
When in doubt, you can even let potted rosemary begin to droop a bit before watering it again.
Once you notice that the soil is dry and the plant looks thirsty, give it a generous, deep watering until water flows out of the bottom drainage hole. The plant will perk up quickly, and you can be sure that you’re not over-watering.
Provide Plenty of Sunlight
This summer-loving herb thrives in full sunshine and needs plenty of light to remain attractive and vigorous. A minimum of 6 hours of direct sun per day will keep potted rosemary happy. Ideally, you can place the plant on a south-facing patio or windowsill throughout the main growing season.
If your home doesn’t get enough direct sunshine, consider growing rosemary beneath a supplemental grow light. The plant will tolerate partial shade but can start to suffer if it doesn’t get enough light.
If your rosemary appears pale, brown, stunted, or lacks its signature fragrance, it could be a sign that it needs more sunlight.
Pick the Right Container
Earthen pots are not only attractive; they’re ideal for regulating the temperature and breathability of your potted rosemary plant.
Clay or terracotta pots are naturally porous, which allows the soil to breathe and dry out after watering. These pots are also great insulators against heat or cold. They don’t warm up quickly in the sun, nor do they get cold at night.
Fabric containers can also do quite well, especially if you are looking for an eco-friendly option that’s easy to move around. Containers like the root pouch seen here can offer an economical option that’s also environmentally friendly. It also makes it easy to move your plants around.
Use Larger Containers When Possible
Even dwarf varieties of rosemary require about a foot of root space to properly support the plant. Whether you’re starting with a cutting or an established seedling, it’s best to plant rosemary in a 12” minimum diameter pot to give it room to go.
With proper pruning, rosemary can stay quite compact above the surface, but the roots need a fair amount of soil volume to anchor into. More soil volume also means greater insulation for your rosemary plant.
Ensure There’s Enough Drainage
Without a drainage hole, where will the water go? You may notice that the theme of soil breathability and drainage is absolutely key for thriving potted rosemary. Before you plant rosemary in a container, check that the pot has a large drainage hole where water can empty into below it.
While there are many aesthetically-pleasing planters on the market, the ones that lack drainage holes are virtually useless!
Prune Once or Twice a Year
Like its cousin lavender, rosemary prefers to get a haircut once or twice a year. Pruning encourages a flush of new growth while shaping the plant and helping it stay compact in size. It also prevents legginess (long, wobbly stems) that could make the potted plant more prone to falling over.
The best time to prune is in the spring after the first flush of flowers fades. If your rosemary doesn’t flower indoors, you can cut it back whenever you notice an abundance of lime green new growth. If your potted rosemary is extra vigorous, you can also prune again in the fall.
When pruning rosemary, remember to:
- Never cut into the woody base of the plant.
- Cut back about ½ to ⅓ of the plant at a time.
- Sharpen and sanitize your pruners before cutting.
- Avoid pulling or tugging the branches.
- Plant into a rounded mini bush or triangle shape.
You can use your rosemary prunings as cuttings to establish more plants, or you can bundle them up and dry them for use in the kitchen.
Maintain Air Circulation
One of the simplest potted herb hacks is to place a fan near your rosemary. Keep air flowing through the fragrant needles to prevent powdery mildew and other foliar diseases. This is especially important in humid climates.
Keep it at Room Temperature
The best temperature for rosemary is between 60 and 75°F. Room temperature in your home is usually ideal. If you want to move your rosemary pot outdoors during the summer, make sure that night time temperatures do not fall below 45°F.
It’s also important that rosemary isn’t exposed to extreme heat. While the plant loves warm sunshine and tolerates drought, it cannot handle scorching summer temperatures.
If your windowsill or patio tends to get blasted by the southern sun, consider moving your rosemary to a slightly shady location during peak summer heat waves.
In zones 8 through 10, rosemary can remain perennial outdoors, whether in a container or in the ground. Most gardeners in zones 7 and cooler will need to bring their rosemary plants indoors before the first frost of fall.
Place Plants Outside in Summer
Potted rosemary can stay indoors for the entirety of its lifespan, but it is more likely to get a lush summer boost when you move it outside for part of the season. A medium-sized clay pot is ideal for this Mediterranean herb because the container is easy to transport and remains insulated against extreme temperatures.
Most gardeners can comfortably bring rosemary outside a few weeks after the last spring frost date. To protect the plant from autumn’s chill, bring it back indoors when the first frost date approaches.
Bring it Inside for Cold Winters
In colder climates, rosemary is likely to go dormant during the winter. It doesn’t need as much light and is unlikely to put on much new growth. Some gardeners even overwinter rosemary in a garage where it can rest in its dormant phase. However, this is not necessary if you want to continue harvesting small sprigs from the plant throughout the winter.
Keep potted rosemary in a place where it is safe from frost and away from cold air drafts. In many homes, it does great when overwintered about 6-12” from a south-facing window.
Keep in mind that rosemary prefers a moderate humidity level of around 50%. When overwintering indoors, don’t place rosemary too close to a heater where it may get dried out.
Treat Pests Early and Often
Thanks to its strong aroma, not many bugs attack rosemary’s leaves. Fortunately, if you notice aphids or spider mites, they are easy to deal with. A diluted solution of neem oil or horticultural soap can be sprayed onto the rosemary leaves to get rid of any pests.
Keep in mind that a potted plant is more prone to spreading pests amongst all of your house plants. If you notice an infestation, move your rosemary away from other herbs immediately.
You may also want to address underlying stressors that could be weakening the plant’s defenses, such as soggy soil, overwatering, or root rot.
Increase Container Size as Needed
If your rosemary is putting on a significant amount of growth every year, this is a good sign that your container-growing methods are a success! However, you don’t want to keep your herbs in the same pot forever or they may become rootbound.
If you up-pot or divide rosemary every year in the spring, the plant can continue to flourish for years to come. Potting up also offers the opportunity to examine your rosemary’s roots and give them a soil refresh.
To pot up rosemary:
- Choose a container that is 50% larger or twice the size of the current pot.
- Fill it halfway with a similar well-drained soil blend.
- Gently grasp your rosemary plant at the base and slowly turn the container on its side.
- The root ball should come out fairly easily and in one piece.
- Slide it back into place, backfill, and let it grow for another year.
- If the plant comes out easily, take a moment to inspect the roots.
- If any areas appear diseased, cut them off with sanitized shears.
- Place the root ball in the new container and gently “fluff” around the root hairs.
- This will loosen any rootbound areas and encourage them to dive into the new soil.
- Backfill so that the soil level is the same as it was in the original pot.
- Avoid burying the crown or stems.
- Optionally, water with diluted kelp to provide minerals and help the plant adjust.
Harvest Often
The final trick to happy potted rosemary is to harvest it frequently! Many gardeners avoid harvesting because they think it might hurt the plant. In reality, regular snipping encourages new growth and keeps the plant happy. Use sanitized, sharp shears to avoid tugging on the stems or introducing disease.
Avoid removing more than half of the plant’s leaves at a time. Ideally, you should harvest a sprig of rosemary here and there as needed. As long as the herb retains the bulk of its foliage, your harvests will promote more growth.
Final Thoughts
Even if you forget everything else in this post, remember: Drainage and irrigation are the most important factors for successfully growing rosemary in a pot!
Remember to:
- Choose an extremely well-drained soil blend.
- Ensure it has aerating ingredients like pumice, gravel, vermiculite, or perlite.
- Never oversaturate rosemary or leave the roots sitting in soggy soil.
- Choose a container with a big drainage hole.
- Earthen or terracotta pots are best because they let the soil breathe.
- Only water rosemary when the upper few inches of soil have dried out.
