Alyssum is a plant made for growing in containers. It can be tucked into any gap to cover areas where earlier blooming plants have finished. Small pots, mixed seasonal plantings, and hanging baskets are perfect for Alyssum’s shallow root system. Give potted Alyssum as much sun as possible, and the blooms will continue to the first freeze of fall.
Planting Alyssum in Pots
Potting up Alyssum early in the spring is ideal. This tender perennial / hardy annual prefers cooler weather and is one of the earliest to bloom. Choose a location that will receive at least 4-6 hours of direct sun and has easy access to water. Alyssum growing in pots will need supplemental watering frequently. Drainage needs to be excellent in any container. Ensure there are many drainage holes and that the potting soil is light and peat-free for the best drainage. Hanging baskets, especially, need a lightweight all-purpose potting mix.
Best Soil For Alyssum in Pots
Choose a peat-free potting soil with added perlite or vermiculite. The perlite helps retain moisture while lightening the soil texture and improving drainage. The drainage holes do not need to be covered with a layer of gravel or other material. This will cause water to collect in the bottom of the pot. Instead, if you are worried about soil washing out of large drainage holes, a coffee filter placed in the bottom of the pot will keep the soil in place and let water drain normally.
Mulching the top of a container with fine gravel helps suppress weed germination and keep the soil cool. Mulching with a thin layer of worm castings on the top of the pot will hold moisture in the soil longer while adding nutrients at each watering.
Caring For Alyssum in Planters
Alyssum makes a fabulous filler plant for just about any container or hanging basket. Regular watering and fertilizing are the only maintenance necessary for a season of lovely scents and blooms.
Watering Alyssum in Pots
Containers of plants need to be watered much more often than plants in the ground. The roots have less space to spread out and find moisture. Water pots when the top 1 inch of soil is dry to the touch. Water thoroughly until the water runs out of the drainage holes. Smaller pots will dry much faster than larger planters and may need watering daily during hot and dry periods.
Humidity is another factor to take into account. The soil will stay damper in climates with high humidity, even during high heat periods. Make sure to match Alyssum to other plants that have the same water requirements. For example, Ferns, Hostas, and Bleeding Hearts require more shade and wetter soil than Alyssum will tolerate.
Fertilizing Alyssum in Pots
A diluted liquid fertilizer applied every 2-3 weeks is enough nutrition to keep potted Alyssum blooming all season. Watering the container or hanging basket will leach nutrients from the soil over time. Supplemental fertilizers keep macronutrient levels consistent. Fertilizing can continue until the first freeze if Alyssum is growing as an ornamental.
Winter Care For Alyssum in Pots
Annual-grown Alyssum will require no extra winter protection. These plants will die back and have completed their lifecycle by the first frost. Seeds can be saved from Alyssum for regrowing in the spring. Treat the plants as hardy annuals and germinate the seed under cover 2 months before the projected last frost for your gardening zone. Plant the new Alyssum out early in the spring when nighttime temperatures exceed 45 degrees F.
In gardening zones 9-11, Alyssum will continue to bloom and grow through the winter with continued fertilization every 3 months and regular watering. A shearing back in the early fall will clean up Alyssum so that new vigorous growth will continue.
Growing Alyssum Indoors
Potted Alyssum does not make a good houseplant. The conditions indoors are too hot and dry to sustain continuous growth. Starting seeds indoors is a great way to get a jump on spring planting late in the winter. Alyssum seeds should be started 8 weeks before the last frost and grown in a warm, very bright spot until they are large enough to plant outside in the spring.