How To Care For Potted Rosemary Plants
Rosemary (Salvia Rosmarinus, formerly Rosmarinus officinalis) is an underappreciated plant that deserves far more attention.
Most people only know rosemary as a culinary herb, but it’s also a valuable companion plant.
However, this member of the Lamiaceae (AKA sage) family is actually quite attractive in its own right, especially when in bloom.
So be prepared to compliment your garden with this wonderful companion as we explore how well-adapted it is for container life.
How To Care For Potted Rosemary Plants
Rosemary is a low-maintenance plant that can be quite forgiving of a little neglect.
Here’s everything you need to know about keeping one in a pot.
Why Use Pots?
There are two schools of thought when it comes to potting rosemary.
First, this plant can handle a wide range of temperatures but will need to come indoors if it gets too cold.
The other is that a sunny kitchen window is perfect for growing a plant you might need to clip while cooking.
In both cases, you can isolate the plant or pair it up with other plants to take advantage of its ability to ward off many pests and even improve the flavor of certain crops.
Keeping An Indoor Or Outdoor Balance
One of the great advantages of keeping rosemary in a container is that you can easily keep it evergreen.
When the weather is nice, and temperatures are above 55° degrees Fahrenheit at night, you can take your rosemary outside and keep it on a deck or patio, or (even better) place the pots near food crops that are prone to caterpillars and other pests.
When the temperatures begin to cool off (or you’re expecting a major heat wave above 85° degrees Fahrenheit), you can bring the rosemary indoors and place it in a sunny window.
The plant may require a little less water in winter but will otherwise continue to thrive all year.
Choosing A Cultivar
There are many cultivars to choose from if you don’t want the basic species, and all are just as good as an herb, but with different flowers or growth habits.
Some great options include:
- ‘Arp’ – cold-hardy cultivar with a lemony scent, upright growth, and light green leaves
- ‘Barbecue’ – stiff stems and a more robust flavor
- ‘Blue Boy’ – dwarf cultivar with delicate purple-blue flowers
- ‘Prostraus’ – a creeper that looks great in hanging baskets
Caring For Potted Rosemary
Rosemary gives a lot back in exchange for very little.
The following conditions will result in a happy and healthy plant.
Rosemary loves the light and will need at least 6 hours of full sun daily.
Indoors, this may require the use of a grow lamp.
The plant will become leggy and more fragile when not given enough light.
Normal household humidity is perfect for rosemary, which becomes vulnerable to fungal infections at high humidity levels.
Aim for a humidity range of 30% to 60% percent.
Note that you can group rosemary with other plants to give it better humidity without resorting to pebble trays or humidifiers.
These plants are well-adapted for a wide temperature range, but they fare best between 55 and 80° degrees Fahrenheit.
The warmer the weather, the more they’ll thrive.
However, only a few cultivars are cold-hardy, and most will die if exposed to anything below 30° degrees Fahrenheit.
Rosemary becomes more drought-tolerant as it matures and has a relatively shallow root system.
Generally speaking, you’ll want to water younger plants when the soil is dry 1” inch down and mature plants once the soil has dried 2” inches down.
A little organic compost sprinkled onto the soil in spring is plenty for this plant.
Alternatively, you can add a dose of 10-10-10 liquid houseplant fertilizer once in spring, following any instructions on the package.
A good cactus or succulent mix is perfect for rosemary.
However, you can also grab some standard potting soil and mix 2 parts soil with 1 part perlite or coarse sand.
The pH range can be anywhere from 6.1 to 7.0.
You should repot your rosemary each spring, graduating to one container size larger as needed.
Replace the soil during this time to ensure the plant has plenty of nutrients and won’t be at risk of a toxic mineral buildup.
Pruning And Harvesting
Chances are, you won’t need much pruning for maintenance if you’re also planning to use rosemary as a fresh herb.
It’s generally best to prune once the flowers have faded, and you can remove up to ⅓ of the plant before it gets too stressed.
This is also a perfect excuse to dry the clippings for cooking or making homemade potpourri, soaps, etc.
Potted Rosemary Propagation
Grabbing a softwood cutting before the plant blooms is a great way to propagate more plants.
However, if you choose to harvest the seeds, be warned that they’re rather notoriously temperamental.
Try sowing approximately 3 weeks before the projected final frost and always sow in bulk since the success rate is often fairly low (as in closer to 30% percent unless you have a green thumb).
Remember, if you’re propagating a cultivar, you should always use cuttings unless you don’t mind the offspring reverting to the original species.
Potted Rosemary Pests And Diseases
Rosemary may be a great repellent plant, but it’s not immune to pests.
Both aphids and spider mites can be a problem, although rosemary has also been known to repel certain aphid species.
The plant is also prone to fungal infections and absolutely hates being overwatered.
Uses For Rosemary
As a houseplant, rosemary provides an attractive display, especially in bloom, and gives off a pleasant scent that sometimes varies between cultivars.
It can be placed near other plants (even in a container) to protect from a variety of common garden pests while also attracting bees.
The clippings can be dried or fresh in teas and cooking, and its extract can help preserve foods with omega-3 oils.
You can also burn the dried leaves as incense or add them to potpourri, and the oil can be used to make scented candles, bath soaps, insect repellent sprays, and other goodies.