It's hard to say whether sweet alyssum earns its name from it heady fragrance or its delicate clusters of white or multicolored blooms. This annual is a showstopper suitable for window boxes and hanging planters, as its foliage trails gracefully, creating a mass of color that lasts from late spring until fall -- as long as it is trimmed regularly and provided adequate water and nutrients.
Trim spent or faded blooms from alyssum regularly to encourage new blooms. This plant sets seed quickly and will cease blooming if old blooms are not removed. Check every few days and trim away any dying flowers with a pair of scissors or garden shears.
Cut alyssum back by several inches if the ends begin to look ragged or the stem begins to brown. This often reveals fresh new growth that quickly comes alive with new blooms.
Cut neglected alyssum back to a height of 2 to 4 inches to revive the plant in midsummer. Hot dry periods or a few days without watering can leave alyssum brown and unattractive. With a good pruning and attention to regular watering it often revives, producing a flush of new blooms.
Water alyssum until water runs freely from the bottom of the pot whenever the soil feels dry to the touch. Hanging baskets and containers may require daily watering during hot spells.
Aylssum fades quickly if water is withheld during the heat of summer.