Rosemary in Zone 9B — Florida

Rosemary is a fantastic addition to any Florida garden. Its distinctive flavor elevates everything from roasted meats to herbal teas, and the aromatic foliage thrives in our sunny environment. Plus, the upright habit adds structure and beauty to your herb garden.

While our summers can be challenging with high humidity and frequent rainfall, rosemary's drought tolerance and preference for well-drained soil make it surprisingly well-suited for our 344-day growing season. With a little attention to planting time and watering, you can enjoy fresh rosemary year-round.

Starting rosemary from seed indoors is possible, but it's not the easiest route for most Florida gardeners. Rosemary germination can be erratic, and the seedlings grow slowly. If you want to try it, sow seeds indoors from early to late November, about 12 weeks before you'd like to transplant them outside.

Use seed trays with a well-draining seed-starting mix. Bottom watering is a good idea to keep the soil consistently moist without overwatering. Place the trays in a warm location with plenty of light – a sunny windowsill or under grow lights works well. Remember, in Florida, our spring is reversed, so you're starting these seeds in the cooler months for a warm-season transplant.

Transplant your rosemary seedlings outdoors in early to late February. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the sunlight and temperature changes.

Choose a sunny spot with well-draining soil and space the plants 24-36 inches apart. Even in February, we can still have some chilly nights, so keep an eye on the forecast and be prepared to cover the young plants if a cold snap threatens. Honestly, though, buying established rosemary plants from a local nursery is often easier and faster than starting from seed.

Rosemary thrives on neglect, especially when it comes to watering. It's very drought-tolerant once established, and overwatering is a common problem in Florida's humid climate. The key is to provide just enough water to keep the soil from drying out completely, but never let it stay soggy.

During our drier fall and spring months, give your rosemary a good watering when the top 2 inches of soil feel dry to the touch – use the "finger test". Usually, about an inch of water per week is sufficient, but adjust based on rainfall. In the wet summer, you might not need to water at all! Always water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our humid environment.

Signs of underwatering include wilting or drooping leaves. Overwatering can cause yellowing leaves and, eventually, root rot. Applying a layer of pine straw or other organic mulch around the base of the plant can help retain moisture and suppress weeds, but avoid piling it up against the stem, which can also contribute to rot.

Rosemary requires minimal pruning. The main goal is to maintain its shape and encourage bushier growth.

Prune lightly after flowering, which usually occurs in spring. Remove any dead or damaged branches and trim back the tips of the stems to encourage new growth. Avoid cutting into the old, woody parts of the plant, as they may not regrow. Give it a general shaping in the spring to keep it looking tidy. As our first frost approaches in late December, there's no need for special pruning.

You can start harvesting rosemary from your plants anytime from early May through mid June, once they are established. Look for healthy, 4-6 inch stem tips.

Harvest by snipping off the tips of the stems, being careful not to take more than one-third of the plant at any one time. This will encourage new growth and keep the plant productive. The woody stems are generally too tough to eat, so stick to the newer growth. Rosemary is a continuous harvest plant, so you can enjoy fresh sprigs throughout the growing season.

As the first frost approaches in late December, you can harvest a larger amount to dry or freeze for use during the cooler months.

Rosemary is generally a low-maintenance plant, but here are a few common problems to watch out for in Florida:

Root Rot from Overwatering *What it looks like:* Yellowing leaves, wilting, and a general decline in plant health. The roots may be brown and mushy. *What causes it:* Overwatering, especially in poorly draining soil. Our heavy summer rainfall can exacerbate this issue. *How to fix/prevent it:* Ensure your rosemary is planted in well-draining soil. Water only when the top 2 inches of soil are dry. Avoid overwatering, especially during the rainy season. Consider growing rosemary in a raised bed or container to improve drainage.

Powdery Mildew *What it looks like:* White or grayish powdery coating on leaves and stems. Leaves may curl, yellow, and eventually die. *What causes it:* Various fungi that thrive in warm days, cool nights, and moderate humidity – conditions that are common in Florida. *How to fix/prevent it:* Improve air circulation around the plant by spacing properly and pruning. Remove affected leaves. Apply neem oil or potassium bicarbonate sprays. A milk spray (1 part milk to 9 parts water) can also be effective.

Spider Mites *What it looks like:* Fine stippling (tiny white dots) on leaves. Fine webbing on the undersides of leaves and between stems. Leaves may turn bronze or yellow. *What causes it:* Tiny arachnids that thrive in hot, dry conditions. Populations can explode during periods of drought stress. *How to fix/prevent it:* A strong spray of water (daily for a week) is often the best treatment. Increase humidity around the plant. Apply neem oil or insecticidal soap.

Florida Specific Challenges Our hot, humid summers and wet-summer rainfall create a perfect environment for fungal diseases like powdery mildew and root rot. Be extra vigilant about watering and air circulation during these months. Also, our sandy soil can drain quickly, so be sure to amend it with organic matter to improve water retention and nutrient availability.

Rosemary is a great companion plant for several vegetables and herbs in your Florida garden. Sage, thyme, and lavender are all good companions because they share similar growing requirements – full sun and well-drained soil. They also attract beneficial insects that can help control pests.

Green beans and carrots benefit from being planted near rosemary because rosemary repels bean beetles and carrot rust flies. Avoid planting rosemary near mint, as mint is very aggressive and can quickly take over the garden, outcompeting rosemary for resources. Plus, mint prefers moist soil, which is the opposite of what rosemary needs.