Rosemary is an excellent indoor herb, identifiable by its erect, shrub appearance and needle-like leaves. Similar to other Mediterranean herbs, it's drought-tolerant and thrives in bright, sunny windowsills. Perhaps best of all, it's highly fragrant and delicious to cook with—a simple brush against the plant with your hand is enough to release waves of delightful rosemary scent. Best planted outdoors in early spring after the final frost, rosemary can grow quickly, often reaching close to three feet within a year. When potted indoors, it benefits from being kept slightly dry and trimmed to remain comfortable within its chosen pot size.
|Botanical name||Salvia rosmarinus|
|Plant type||Herbaceous perennial|
|Mature size||12–14 in. tall and 6–12 in. wide (indoors); 2–6 ft. tall and 2–4 ft. wide (outdoors)|
|Sun exposure||Full sun|
|Soil type||Loamy, well-drained|
|Soil pH||Neutral to acidic|
|Flower color||White, pale blue|
|Hardiness zones||8–10 (USDA)|
One of the most popular Mediterranean herbs, rosemary is beloved by many gardeners for its culinary perks and a beautiful, relaxing scent. It can be grown both indoors and outdoors (in USDA zones 8-10), though it takes considerably more tending-to and attention as a houseplant. It thrives on lots of light and the right watering cadence, ensuring its loamy soil stays well-hydrated without getting waterlogged. Temperature is important to the rosemary plant too, and efforts should be taken to mimic its natural Mediterranean outdoor environment as best as possible. With proper care, an indoor rosemary plant can provide months of delicious scents and culinary treats.
The rosemary plant is accustomed to full sunlight when grown outdoors and is only moderately tolerant of a bit of shade. This can cause issues when the plant is grown (or moved) indoors, as it's difficult to achieve the right sunlight conditions indoors naturally. Potted rosemary should be kept on a bright windowsill that receives light all day, or in a well-lit room, like a sunroom. If you're looking to move potted rosemary that has been outside all summer into your home for the fall and winter months, first put it on a sunlight "diet," moving it to the shade for a few hours every day so it gradually gets used to reduced light and therefore is not shocked when relocated indoors.
Rosemary plants prefer dry, well-drained soil reminiscent of their Mediterranean upbringing. A sandy cactus soil blend works best for planting, but you can also try mixing sand into a traditional potting mix to make it lighter and airier. In order to ensure proper drainage, choose a pot with adequate holes at its base—one made of moisture-wicking clay or terracotta can help too.
When it comes to watering a rosemary plant, it can be tricky to strike the right balance. When it doubt, err on the side of underwatering your plant, as it's much more likely to die from too much water rather than too little. A good rule of thumb is to water a rosemary plant when the top of the soil has dried out but never to let all the soil dry out completely. Additionally, rosemary is known as an "upside-down" plant, meaning it prefers to absorb its moisture through the air. Therefore, gently misting the plant every ten days or so can help fill the gap between waterings.
Temperature and Humidity
Excess amounts of humidity can actually pose a threat to rosemary, causing powdery mildew to cover the leaves of the plant, giving them a dusty, white appearance. To avoid this, ensure that it is placed somewhere fairly dry (not a bathroom) and consider housing it near consistent air circulation, like on an open windowsill or next to a fan. Temperature-wise, rosemary is considered fairly hearty and can thrive in temperatures down to 50 degrees Fahrenheit, or up to 80 degrees.
For best results, feed your rosemary using a liquid fertilizer at the start of its growing season (spring) and continuing monthly through the fall. If you're keeping organic in the hopes of cooking with your rosemary, be sure to use an organic fertilizer or fortify the soil with compost instead.
Watch Now: How to Grow and Care for Rosemary
Rosemary is a fairly slow-growing plant, so it's usually easiest to buy nursery-grown plants rather than start your own from seed. However, rosemary can be successfully started from seed if you don't mind waiting for the plant to fill in. Alternatively, you can take leaf-tip cuttings of established plants to start new ones. This is a particularly good idea if you have an outdoor plant that might not make it through the winter. Start a new cutting in the summer months in a container, then bring it inside when the weather begins to cool off. Not only will it provide rosemary all winter long, but it can also help kick off your herb garden next spring.
Unlike many other herbs, rosemary can grow into a substantial plant of up to 48 inches. Not many people have room for a massive rosemary plant in their homes, so the subject of repotting depends on your goals. If you'd like to keep your rosemary smaller and manageable, repot in the spring into the same size pot. During repotting, root prune the plant to stunt its growth by snipping off about one-third of the root material, then placing the plant back into the same size container with fresh soil. If you'd like a larger plant, step up the pot size and repot normally.