How to Grow Rosemary for a Flavorful and Ornamental Addition to Your Garden

Rosemary is known for adding beautiful aroma and flavor to culinary dishes, but it's not just a delicious herb! Rosemary shrubs can be grown in ornamental gardens, too. It makes for a robust and fragrant perennial shrub in warmer climates and can even serve as erosion control.

Rosemary has been used medicinally at least from the time of the ancient Greeks and Romans around 500 B.C. Native to the warm Mediterranean region, rosemary is hardy in USDA zones 7-10. In cooler regions, it is typically an annual plant but it can be wintered indoors when potted.

With the proper light, water, temperature, soil, and fertilizer, rosemary has been known to live as long as 30 years.

Quick Rosemary Facts

How to Care for Rosemary

Rosemary plants are fairly low maintenance and make a wonderful addition to any herb garden. They are drought tolerant and thrive indoors and out with little tending. The most important thing is to ensure rosemary plants don't get overwatered or soggy.

Rosemary Light Needs

Rosemary should be grown in full sun; at least 6 hours of direct sun. If growing it indoors, rosemary needs a south-facing window and often supplemental grow lights. Barrina T5 grow lights, available from Amazon, are full spectrum and will give your rosemary proper light conditions indoors.

Watering Rosemary

Rosemary prefers its soil on the dry side. It should be watered every week and a half to two weeks in the ground and once a week if it is container-grown. Before watering rosemary, check the top inch (2.5 cm) of soil with your finger. If it is dry to the touch, water the herb. Avoid overhead watering as its can lead to fungal infections. Bottom-watering potted rosemary can ensure the foliage stays dry.

Temperature & Humidity

Rosemary likes warm temperatures with moderate humidity. Rosemary plants can have fungal problems when humidity is too high. They are native to the Mediterranean so it is best to mimic those conditions; dry, breezy and warm. Proper air circulation is important for success. Prostrate rosemary plants, or creeping rosemary, are most likely to encounter issues from humidity and damp.

While most varieties tolerate high temperatures, they prefer a range of 55-80 F (13-27 C). Most varieties will die at temperatures below freezing. You can winterize rosemary plants to protect them from moderate cold, or just bring potted rosemary indoors in the colder months.

Rosemary Soil Needs

Most cultivars of rosemary thrive in well-draining, slightly acidic, loamy soil with a pH of 6.0-7.0. It tolerates drought well which makes it a nice addition to a water-wise garden. If you are planting rosemary in containers, a well-draining herb mix like this Rosy Soil herb potting mix from Amazon is a good choice. You should also ensure your container has a drainage holes to avoid soggy soil.

Fertilizer for Rosemary

Generally, rosemary grown in the ground will not need fertilizer however, even they will benefit from light fertilization. Feed them with a slow-release fertilizer for shrubs and trees or an organic fertilizer in the late winter or early spring. Sap-sucking pests are attracted to plants that have had too much nitrogen fertilizer applied.

Rosemary Pests & Diseases

Rosemary is quite resistant to pests however, spider mites, mealybugs or scale insects may attack the plant. A good spray of water or insecticidal soap can remove the majority of sap-sucking insects. Scales can easily be removed by pruning the tips of the plant where these sedentary pests are found.

Overwatering encourages root rot. The entire plant will become limp and its terminal shoots die off. Dig up the plant and prune out infected roots then dust with fungicide powder. If the root system is black and mushy, throw the plant away.

Brown rosemary plants signal issues like root rot, extreme dehydration, winter burn, high humidity stress, or soil pH issues.

Planting Rosemary

Rosemary can be planted in the garden proper or grown as a container plant either indoors or outside. It can be grown in dry to medium soil that is well-draining, in full sun although it will tolerate light shade. Heavy clay soil should be avoided.

Growing Rosemary in Pots

Rosemary is often grown in containers, especially in areas where it's considered an annual. Containers should have adequate drainage holes.

The potted rosemary can be grown outside until temperatures begin to drop in the fall and then brought indoors and placed in a sunny southern window that provides at least 6 hours per day of full sun. Supplemental light may be needed in the form of grow lights.

Plants in pots generally need more frequent irrigation than those grown in the ground and this is true of rosemary when it is outside. However, avoid overwatering which can foster fungal diseases. Only water when the top inch (2.5 cm) of soil feels dry to the touch.

Take overwintered rosemary outside again in the mid-spring when temps have warmed and the last frost has passed.

Repotting

Rosemary should be repotted each year in the spring. Remove the plant from its container, loosen the roots gently, and place it at the same depth in a new pot that is one size up from the last, then fill in around the plant with fresh potting medium.

Overwintering

Overwintering rosemary is an option for plants that are in slightly cooler than ideal climates. Rosemary should be moved if it is in an area that gets freezing temperatures. If it is container grown, the plant can be moved inside and cared for much as a houseplant or, it can go in a protected garage or shed and be allowed to go dormant until spring.

Plants that remain in the ground can be covered with burlap bags or chicken wire enclosures filled with dry leaves to protect them from the cold. It is also best to situate plants on the south or west side of the house so they can benefit from the protection of the foundation.

Also protect the roots of the plants by covering them with 5-6 inches (13-15 cm) of wood chips.

Pruning Rosemary

To get a bushier plant, prune rosemary after it blooms to encourage new growth. Since this is a woody herb, always use very sharp, sterile pruning shears to make your cuts.

Rosemary may be pruned at any time during the spring or summer; up until 4-6 weeks prior to the first frost for your area. Do not prune the plant after this point as pruning facilitates new growth which could then freeze and harm the plant. Reviving woody rosemary in late winter is another option that can rejuvenate rosemary plants.

Rosemary plants can be pruned into topiaries, but never remove more than 1/3rd of the foliage at any one time. Doing so can kill the plant.

How to Propagate Rosemary

Rosemary can be grown from seed although germination rates are low and it takes some time (up to three years) for the herb to grow large enough to harvest from. Otherwise, rosemary propagation is more commonly done through cuttings.

Cuttings should be taken from mature plants. With a sharp, sterile knife or pruning shear, cut a 4-6 inch cutting in the late spring to early summer. Be sure your cutting is not blooming.

Remove the lower leaves from the cutting and place it immediately into a room temperature glass of water. In warmer temperatures, roots should grow within a few weeks; longer if it's colder.

When the roots are half an inch long, its time to transplant them into a well-draining, sandy soil medium and place them in a sunny area.

Rosemary Varieties

There are many varieties of rosemary, some upright and some prostrate in habit. Their blooms may be blue, pink or white, and some cultivars are more hardy than others.

Some of the more common cultivars include Albus, Arp, Collingwood Ingram, Creeping, Gorzia, Lockwood de Forest, Majorca Pink, Officinalis, Salem, Spice Island or Tuscan Blue. 'Tuscan Blue' rosemary plants, available from Fast Growing Trees, are wonderfully aromatic plants and easy to care for.

Companion Plants for Rosemary

Rosemary is a good companion plant for most herbs such as basil, sage, thyme and oregano. It also makes a good companion plant for bloomers such as sunflowers, marigolds, and nasturtiums and settles in nicely with root veggies like carrots.

Rosemary Plant Uses & Benefits

In the garden, rosemary is suited for use in rock, winter, edible, cutting, pollinator, butterfly, childrens and other gardens. It does well in containers or as a border or low hedge as well as areas where it can trail.

Leaves can be used either fresh or dried in a variety of menus from steaks to stews to breads, herbal butters or vinegars. The flowers and leaves are used in sachets and potpourri and the oil is pressed for use in a variety of cosmetics and toiletries. Sprigs of rosemary make wonderful additions to winter simmer pot recipes. You can even use rosemary to decorate for the holidays!

Rosemary has a long history of use medicinally. It is said to be antimicrobial, anti-inflammatory, and antioxidant. It is also purported to aid in alleviating pain, improving memory, promoting hair growth, and improving circulation.

Rosemary is also a good plant for areas with deer as they avoid the plant.

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