Sweet Alyssum in Zone 10B — Florida

Sweet Alyssum is a fantastic addition to any Florida garden, adding a delicate sweetness and charm. Its low-growing, spreading habit makes it perfect as a living mulch or ground cover, while its fragrant flowers attract beneficial insects. Plus, you can enjoy its beauty during our prime growing season.

Our Florida gardening calendar is different, and summer is the slow season. But don't worry, the reversed growing seasons mean you can plant Sweet Alyssum during our cooler months. With a 360-day growing season, you have plenty of time to enjoy this delightful plant.

Starting Sweet Alyssum indoors isn't always necessary in Florida, but it can give you a head start. If you want to get a jump on the season, begin your seeds indoors from early to late November, about six weeks before you plan to transplant. Use seed trays with a good seed-starting mix and provide gentle warmth and light.

Bottom watering is a great way to keep the soil moist without overwatering, which is important with our high humidity. Remember, our spring character is reversed, so you're starting these indoors right before our cooler, drier weather kicks in.

Transplant your Sweet Alyssum seedlings outdoors from late December through early February. Before transplanting, harden them off by gradually exposing them to outdoor conditions for about a week. This helps them adjust to the Florida sunshine and temperatures.

Space the plants about 6-8 inches apart to allow for their spreading growth habit. Keep an eye on the weather, and if we get an unexpected cold snap, protect the young transplants with row covers or blankets.

Direct sowing Sweet Alyssum is a viable option in Florida, especially if you prefer a more hands-off approach. Sow seeds directly into the garden from late December through early November. The cooler temperatures and lower humidity make this a great time for seed germination.

Prepare the soil well by loosening it and adding compost. Gently press the tiny seeds into the soil, keeping them about 6-8 inches apart. Keep the soil consistently moist until the seedlings emerge. One thing to consider is that direct-sown plants may take a little longer to mature than transplants.

Sweet Alyssum needs moderate watering, especially in our sandy Florida soil. While it can handle some dryness, it's not truly drought-tolerant and will suffer in extreme heat if not watered regularly. During our cooler months, from late fall through early spring, water deeply once or twice a week.

Use the "finger test" – stick your finger about 2 inches into the soil. If it feels dry, it's time to water. Aim for about 1 inch of water per week, either from rainfall or irrigation. It's best to water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our humid climate.

In the summer, Sweet Alyssum may go dormant or die back, especially with our hot temperatures and wet-summer rainfall. During this time, reduce watering to just enough to keep the soil from completely drying out. Signs of underwatering include wilting leaves, while overwatering can lead to yellowing leaves and root rot.

A light layer of mulch, like pine straw or wood chips, can help retain moisture in the soil and suppress weeds. Just be sure to keep the mulch away from the base of the plants to prevent rot.

Sweet Alyssum requires minimal pruning, but a little maintenance can keep it looking its best. When the plants start to get leggy, usually in midsummer, shear them back by about half. This encourages fresh growth and a new flush of flowers.

Use sharp pruning shears to make clean cuts. Don't worry about being too precise – Sweet Alyssum is resilient and will bounce back quickly. As our first frost approaches around late December, you can let the plants go to seed or remove them to prepare the bed for other crops.

Sweet Alyssum is primarily grown for its beauty and ability to attract beneficial insects, not for direct harvest. Expect the first flush of flowers starting in early February and continuing through early January. No need to harvest individual flowers.

The plant will continuously produce blooms, creating a carpet of color and fragrance. If you're using Sweet Alyssum as a living mulch, simply enjoy its benefits throughout the growing season.

As the first frost approaches in late December, you can either let the plants naturally fade or remove them to make way for new plantings. Consider saving some seeds from the healthiest plants for next year's garden.

Here are a few common issues you might encounter with Sweet Alyssum in Florida:

Downy Mildew

• What it looks like: You'll see yellow patches on the tops of the leaves, with a fuzzy, gray-purple growth on the undersides. The leaves will start to brown and die, starting from the bottom of the plant.
• What causes it: This is caused by an oomycete pathogen that thrives in cool, humid conditions. The spores are carried by the wind, making it a common problem in our wet-summer climate.
• How to fix/prevent it: Remove affected leaves immediately to prevent the spread. Improve air circulation around the plants by spacing them properly. Water at the base, avoiding overhead watering. You can also use copper-based fungicides as a preventative measure.

May Die Back in Extreme Heat

• What it looks like: During the hottest part of the summer, the plants may appear stressed, with wilting or browning leaves. In severe cases, the entire plant may die back.
• What causes it: Sweet Alyssum prefers cooler temperatures. Our hot summers can be too much for them, especially with our high humidity.
• How to fix/prevent it: Provide some afternoon shade during the hottest months. Water deeply but less frequently. Don't fertilize during this time, as it can stress the plants further. They will often bounce back when temperatures cool down.

Flea Beetles

• What it looks like: You'll notice tiny, round holes (shot-hole pattern) in the leaves. If you look closely, you might see small, dark beetles that jump when disturbed.
• What causes it: These are flea beetles, small jumping beetles that feed on the leaves. They're most damaging to young seedlings.
• How to fix/prevent it: Protect seedlings with row covers during their vulnerable stage. Delay planting until the plants are larger and more resilient. You can also try using kaolin clay coating or neem oil spray. Interplanting with basil or catnip can help deter these pests.

Florida Specific Challenges: Our extreme humidity, especially during the wet-summer months, can create ideal conditions for fungal diseases like downy mildew. Be sure to provide good air circulation and avoid overhead watering. The summer heat can also stress the plants, so providing some shade and reducing watering during this time is crucial.

Sweet Alyssum makes a great companion plant for several vegetables in your Florida garden. Plant it near broccoli to attract beneficial insects that prey on broccoli pests. It also works well with potatoes, as it can help deter potato beetles.

Lettuce also benefits from Sweet Alyssum, as the fragrant flowers attract pollinators that can improve lettuce seed production. I would avoid planting it near anything that competes aggressively for nutrients, as our sandy soil doesn't hold nutrients well.