Sweet Alyssum in Zone 10A — Florida

Sweet Alyssum is a winner here in Zone 10A. It's a beautiful, fragrant, low-growing plant that serves as a living mulch and attracts beneficial insects to your garden, which is always a plus. Plus, you can get a great bloom in the cooler months when other flowers are taking a break from the intense Florida heat.

Our Florida gardening calendar is different, and summer is definitely the slow season. But with Sweet Alyssum, you can plant in fall, harvest in winter, and enjoy a burst of color before the real heat kicks in. Our 355-day growing season gives you plenty of time to make it work.

Starting Sweet Alyssum indoors isn't strictly necessary in our climate, but it can give you a head start. If you want to get a jump on the season, aim to start your seeds indoors from early to late November, about six weeks before you plan to transplant them.

Use seed trays filled with a good seed-starting mix. Keep them warm and provide plenty of light – a simple grow light works wonders. Bottom watering is a great way to keep the soil moist without encouraging fungal diseases, which are always a concern with our humidity. Remember, our spring character is reversed here, so getting plants established early is key.

Transplant your Sweet Alyssum seedlings outdoors from late December through early February. This gives them time to settle in before our (very) short, mild winter ends. Before you move them permanently, harden them off by gradually exposing them to outdoor conditions for about a week.

Space the plants 6-8 inches apart to allow for their spreading growth habit. Keep an eye on the weather forecast; even though we're in Zone 10A, occasional cool snaps can still happen during this time.

Direct sowing Sweet Alyssum is a perfectly viable option in our Florida climate. You can direct sow outdoors from late December through early November. The key is getting the timing right to avoid the worst of the summer heat.

Prepare your soil well, ensuring it's loose and well-draining. Sweet Alyssum seeds need light to germinate, so don't bury them too deeply. Keep the soil consistently moist until the seedlings emerge. Space the seeds about 6-8 inches apart or thin the seedlings later.

Sweet Alyssum needs moderate watering to thrive, but it's not drought-tolerant, so you have to pay attention, especially during our dry spells. During the cooler months, when rainfall is less frequent, aim to water deeply once or twice a week. The finger test is your friend – stick your finger about two inches into the soil; if it feels dry, it's time to water.

In the summer, Sweet Alyssum may go dormant due to the extreme heat. Even though our summers are wet, the rainfall is often sporadic. During this period, water deeply only when the soil feels dry, but don't overdo it. Too much water combined with our humidity can lead to fungal problems.

Water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our humid environment. Signs of underwatering include wilting leaves, while overwatering can lead to yellowing leaves and root rot. A layer of pine straw mulch can help retain moisture and suppress weeds, which is always a plus in Florida.

Sweet Alyssum requires minimal pruning, but a little maintenance can keep them looking their best. When the plants get leggy in midsummer (and they will), shear them back by about half. Don't worry, they'll bounce back quickly with fresh growth and flowers once the temperatures cool down a bit.

Just snip off the spent flower heads to encourage more blooms. As our first frost approaches around late December, you can leave the plants in place. They may survive a light frost, and if not, they'll decompose and add organic matter to your soil.

Sweet Alyssum is primarily grown for its ornamental value and ability to attract beneficial insects rather than for harvesting. You'll start seeing flowers around early February if you planted in fall, and they'll continue blooming throughout the cooler months.

The flowers are continuously produced, so there's no need to "harvest" in the traditional sense. Simply enjoy their beauty and the pollinators they attract. To encourage continued production, deadhead spent flowers regularly.

As our first frost approaches in late December, you can simply let the plants be. They may survive a light frost and continue to provide some color, or they will decompose and add nutrients to your soil. Either way, they've done their job!

Sweet Alyssum, like many plants in Florida, can face a few challenges. Here are some common problems and how to deal with them:

Downy Mildew

• What it looks like: Yellow patches on the tops of leaves, with fuzzy gray-purple growth on the undersides. Leaves brown and die, starting from the bottom of the plant.
• What causes it: This is caused by an oomycete pathogen that spreads in cool, humid conditions via wind-carried spores. Our high humidity makes this a common issue.
• How to fix/prevent it: Remove affected leaves immediately to prevent spread. Improve air circulation around the plants. Water at the base, never overhead. You can use copper-based fungicides as a preventative measure. Look for resistant varieties when possible.

Heat Die-back

• What it looks like: Plants will start to wither and brown, often looking burnt, during the hottest part of the summer.
• What causes it: Our intense summer heat is simply too much for Sweet Alyssum.
• How to fix/prevent it: Provide some afternoon shade if possible. Water deeply but less frequently during the hottest periods. Shearing the plants back can sometimes help them recover when temperatures cool.

Flea Beetles

• What it looks like: Tiny round holes (shot-hole pattern) in the leaves. You'll see small, dark beetles that jump when disturbed. Young seedlings are most vulnerable.
• What causes it: These are small jumping beetles that feed on the leaves.
• How to fix/prevent it: Row covers can protect seedlings during their vulnerable stage. Delay planting until plants are larger and more resilient. You can try kaolin clay coatings or neem oil sprays. Interplanting with basil or catnip can also deter them. Healthy, vigorous plants tend to outgrow the damage.

Florida Specific Challenges: Our hot, humid, and wet summers create a perfect environment for fungal diseases. The extreme heat can also stress the plants, making them more susceptible to pests and diseases. Make sure to provide good air circulation, water at the base of the plants, and choose disease-resistant varieties whenever possible.

Sweet Alyssum makes a great companion plant in our Florida gardens. It attracts beneficial insects that can help control pests on other crops.

Good companions include broccoli, potato, and lettuce. Sweet Alyssum attracts hoverflies and other beneficial insects that prey on aphids, which can be a problem for broccoli and lettuce. It also helps attract pollinators to potato flowers, potentially increasing yields. Avoid planting it near plants that are highly susceptible to flea beetles, as it can sometimes attract them.