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Fragrant, savory rosemary is one of our favorite herbs to use in the kitchen. This hardy Mediterranean native also makes a striking addition to your garden or houseplant collection. Here's everything you need to know to grow rosemary indoors or outdoors.
- Botanical Name: Salvia rosmarinus
- Common Name: Rosemary
- Plant Type: Evergreen shrub
- Mature Size: Two to six feet tall and two to four feet wide
- Sun Exposure: Full sun
- Soil Type: Well-drained soil
- Soil pH: 6.5 - 7.0
- Toxicity: Nontoxic
Plant rosemary seedlings outdoors in spring after the danger of frost has passed for your area. Water when the soil has dried out around the roots. This may be as often as one or two times per week in very hot, dry weather or rarely in winter. Since it's native to warm, dry climates, rosemary is susceptible to root rot when overwatered.
Pot your indoor rosemary plants in terra cotta pots to avoid overly wet soil. Water when the top of the soil surface has dried out, cutting back on watering during the cold winter months.
Rosemary is a light feeder, meaning it does not need to be fertilized much. However, your rosemary plant may benefit from an application of slow-release fertilizer designed for shrubs or an organic houseplant fertilizer diluted to half strength for potted plants in the spring.
In warm climates, rosemary can bloom in spring, summer, and even during mild winters. Lightly prune your rosemary plant after it blooms to promote fuller, bushier growth. You can even prune it into topiary-style shapes.
Best Growing Conditions for Rosemary
Outdoors, plant rosemary in a spot with full sun for at least six hours per day and with well-drained soil. Avoid spots with heavy clay soil, which can impede drainage and kill your rosemary plant.
If you're keeping your rosemary indoors as a houseplant, put it in the sunniest window in your house, ideally a south-facing or west-facing window. Avoid humid spaces like bathrooms, as rosemary plants are susceptible to powdery mildew. One way to avoid this is to have a small fan blow on the plant for a few hours each day.
Types of Rosemary
There are many cultivars of rosemary available, but the main difference between types is growth habit. Some, like 'Tuscan Blue' and 'Golden Rain,' are upright shrubs that will grow taller than other types. Others are semi-upright or dwarf varieties, meaning they're shorter and wider but still grow vertically, like 'Collingwood Ingram.' These types tend to have stronger flavor and aroma when used in cooking.
There are also trailing or creeping varieties, which make excellent ground cover when planted outdoors. They'll also spill attractively out of containers kept indoors or outdoors.
How to Propagate Rosemary
The easiest way to propagate rosemary is by rooting stem cuttings, as rosemary can be difficult to grow from seed. You'll have the best success in spring or summer when the plant has new, tender growth. Here's how to propagate rosemary:
What You'll Need
- Healthy, mature plant
- Clean, sharp shears or pruners
- Small plant pot
- Soilless growing medium such as a blend of equal parts coconut coir and coarse sand
- Rooting hormone powder
Step 1: Select a healthy, leafy stem on the mature plant that is still green and tender, not hard and woody. Make a diagonal cut about six inches from the tip of the stem. Remove the leaves from the lower half of the cutting.
Step 2: Fill small plant pots with soilless medium. Moisten the soil with water.
Step 3: Dip the cut end of the rosemary cutting in rooting hormone powder, then plant the cutting in the soil so that the leafless bottom half of the cutting is beneath the soil line.
Step 4: Put the pot in a warm place with bright, indirect light. Keep the growing medium evenly moist but not soggy.
Step 5: When you see new leaf growth and the stems stay put when you gently tug on them, the rosemary cuttings have rooted. This process can take anywhere from one to two months. Once cuttings are rooted, you can replant and care for them as usual.
Common Problems With Rosemary
The same piney, aromatic oils that make rosemary smell and taste so good also help to repel insects. Instead of pests, excess moisture and cold are rosemary's weak spots.
Overwatering or poorly drained soil will cause the roots to rot and kill the plant. To avoid this, plant outdoor rosemary in well-drained soil. Indoors, avoid overwatering, and keep potted rosemary in a terra cotta container that will release moisture more quickly than plastic or glazed ceramic.
A hard frost can kill an unprotected rosemary plant. Cover plants with an old sheet or row cover in cold climates during winter freezes. Another option is to keep your rosemary in containers, then bring it indoors for the winter to protect it from the cold.
Are Rosemary Plants Easy to Care For?
Yes, once they are established, rosemary is a very easy, low-maintenance plant to grow.
How Long Can Rosemary Live?
These hardy perennial evergreen shrubs can grow for decades in the right conditions with proper care.
Can Rosemary Grow Indoors?
Yes, rosemary can grow indoors, but it needs at least six hours of sunlight per day to survive. Keep it in a bright, south-facing window, or use a grow light to create these conditions indoors.