Sweet Alyssum in Zone 8A — Florida

Sweet Alyssum is a winner here in Florida because it adds a touch of delicate beauty to your garden, especially when our reversed seasons mean you're craving color. The subtle fragrance is lovely, and it attracts beneficial insects, which is always a plus. It's a great living mulch too.

Our Florida gardening calendar is different, and summer can be brutal. However, with a 283-day growing season, you can easily time your Sweet Alyssum plantings to enjoy blooms throughout the cooler months.

Starting Sweet Alyssum indoors isn't essential in our climate, but it can give you a head start. If you want to get a jump on the season, aim to sow seeds indoors from late December through mid January, about six weeks before you plan to transplant. Use seed trays with a good seed-starting mix, and keep them warm and well-lit.

Consider bottom watering your seed trays to prevent damping-off, a common issue with our high humidity. Remember, spring comes early here in Florida, so starting indoors is more about getting a head start than escaping the cold.

Once the weather starts to warm up in mid February through late March, you can transplant your Sweet Alyssum seedlings outdoors. Be sure to harden them off first by gradually exposing them to outdoor conditions for about a week. This will help them adjust to the Florida sunshine and humidity.

Space the plants about 6-8 inches apart to allow for their spreading growth habit. Keep an eye on the weather forecast, as unexpected cool snaps can still occur during this time of year.

Direct sowing is a great option for Sweet Alyssum in Florida, and is probably the easiest way to grow it. You can sow seeds directly into your garden beds from mid February through early October. Just make sure the soil is well-draining and has warmed up a bit.

Gently press the seeds into the soil, keeping them about 6-8 inches apart. Keep the soil consistently moist until the seedlings emerge. Direct sowing is especially convenient because you can avoid the hassle of transplanting.

Sweet Alyssum likes consistent moisture, but it doesn't want to be waterlogged, and the high humidity in Florida will make it easy to overwater. During our typically drier spring (late February through May), aim to water deeply once or twice a week, providing about an inch of water each time. Use the finger test – if the top two inches of soil feel dry, it's time to water.

In the wet summer months, you may not need to water at all unless we're experiencing a dry spell. Always water at the base of the plants to avoid wetting the foliage, which can encourage fungal diseases in our humid climate. Yellowing leaves can indicate overwatering, while wilting leaves suggest underwatering.

A layer of pine straw mulch can help retain moisture and suppress weeds, but be careful not to overdo it in the rainy season. Remember that Sweet Alyssum may go dormant in the hottest part of summer, so don't be alarmed if it looks a little sad. It will usually bounce back when temperatures cool off.

Sweet Alyssum is pretty low-maintenance, but a little pruning can keep it looking its best. The main thing you'll want to do is shear back the plants by about half when they start to look leggy, usually in midsummer. This encourages fresh growth and more flowers.

Don't be afraid to cut them back hard – they're pretty resilient. As the first frost approaches around early December, you can let the plants go to seed or pull them out if you're ready to plant something else.

Since Sweet Alyssum is mostly grown for its ornamental value and its ability to attract beneficial insects, there isn't a traditional "harvest." You can expect the first blooms about 45 days after planting, and they'll continue to flower throughout the cooler months, generally from late March through mid December. There's no real harvesting needed since it is more of a living mulch and insect attractant.

To encourage continuous blooming, deadhead spent flowers. As the first frost approaches in early December, you can either let the plants go to seed or remove them to prepare for your winter crops.

Even though Sweet Alyssum is fairly easy to grow, you might run into a few problems here 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 then brown and die, starting from the bottom of the plant. *What causes it:* Downy mildew is caused by an oomycete pathogen that thrives in cool, humid conditions. The spores are spread by wind, making it a common problem in our wet-summer climate. *How to fix/prevent it:* Remove any affected leaves immediately. Make sure your plants have good air circulation. Water at the base of the plants, and consider using a copper-based fungicide as a preventative measure. If possible, choose downy mildew-resistant varieties.

Heat Dieback *What it looks like:* The plant may wilt, turn brown, and seemingly die back during the hottest part of summer. *What causes it:* This is simply due to the extreme heat we experience in Florida during the summer months. Sweet Alyssum prefers cooler temperatures. *How to fix/prevent it:* Provide some afternoon shade during the hottest months. Water deeply but less frequently. Don't fertilize during this time. The plants will often recover when temperatures cool down.

Flea Beetles *What it looks like:* You'll notice tiny, round holes (a "shot-hole" pattern) in the leaves. Small, dark beetles that jump when disturbed are often present. *What causes it:* Flea beetles are small jumping beetles that feed on the leaves of various plants. They're most damaging to young seedlings. *How to fix/prevent it:* Use row covers to protect seedlings during their vulnerable stage. You can also try coating the plants with kaolin clay or spraying them with neem oil. Interplanting with basil or catnip may help deter the beetles.

Florida Specific Challenges Our hot, humid summers and sandy soil can be tough on Sweet Alyssum. The high humidity encourages fungal diseases, and the heat can cause the plants to go dormant or even die back. Be sure to choose well-draining soil, water carefully, and provide some afternoon shade to help your Sweet Alyssum thrive.

Sweet Alyssum makes a great companion plant in the Florida garden, and can serve as a living mulch around taller plants.

Good companions:

• Broccoli: Sweet Alyssum attracts beneficial insects that prey on broccoli pests.
• Potato: The flowers attract pollinators that can improve potato yields.
• Lettuce: Sweet Alyssum provides ground cover, helping to retain moisture in the sandy soil and suppress weeds around lettuce plants.

Bad companions:

• There are no known bad companions for Sweet Alyssum. It's generally a beneficial plant to have around.