Alyssum is a low-growing tender perennial, which blooms non-stop from early spring until the first frost. While Alyssum is a tender perennial in USDA growing zones 9-11, it is grown as a hardy annual in the rest of the hardiness zones. Alyssum prefers cooler temperatures and is at its best in spring and fall. Lobularia maritima is the scientific name for Sweet Alyssum. Other plants commonly referred to as alyssums are in the extensive mustard family, which is a different genus. A common pest in grazing meadows is Hoary Alyssum, scientifically named Berteroa incana. Sweet alyssum is not only used to fill hanging baskets and containers of mixed seasonal plantings, but it is useful in organic farming as a natural weed suppressant, a catch crop that combats pests, and a beneficial insect and pollinator attractant.
Choose a spot for Alyssum that receives at least 4 hours of direct sun. Alyssum also is not choosy about the pH of the soil as long as it is not too acidic or too alkaline. Well-draining soil is essential. Alyssum does not tolerate waterlogged soil at any time of the year. Mulching with organic material around the base of Alyssum will not only slowly feed the soil but also help it retain moisture and stay cooler.
Alyssum needs soil that stays consistently moist but is still free draining. Alyssum requires approximately 1 inch of water a week if no natural rain falls. Regular watering throughout the week is necessary for either garden-grown or container-grown Alyssum. The shallow root system can be encouraged to grow deeper in the soil by watering 2-3 times a week instead of daily watering. Depending on the pot size, container-grown Alyssum may need watering daily during hot spells. Perennial-grown Alyssum will require regular watering throughout the winter when the nighttime temperatures exceed 45 degrees F.
Alyssum is a nonstop bloomer that requires regular applications of fertilizer. Fertilizers formulated for blooming plants are referred to as blooming and rooting mixes. Alyssum growing as an annual can be fertilized up until the first frost, when it will die back. Diluted liquid fertilizer may be easier to use for containers. Granular slow-release fertilizers are easiest to use for garden-grown Alyssum. Look for a ratio of NPK that is 0-10-5 or 1-4-2. Good brands are Alaska Bloom Mor liquid feed or Espoma Blooming plant slow-release fertilizer. Apply according to the manufacturer's suggestion.
Pruning for Alyssum is a simple task. At mid-summer or any other time Alyssum looks shaggy and untidy, the whole plant can be cut back by ½. This type of pruning is called a shearing back. This pruning helps the plant to rest and recover for later rebloom. Hot summer temperatures will also slow down the flowering of Alyssum. After shearing back, make sure to water the plant well and give a light feeding of fertilizer. Don’t worry about deadheading. The flowers continue to form as the flower stem grows longer.
Caring For Alyssum in Pots
Alyssum can adapt to just about any type of container you choose. The compact mounding shape and profuse blooming make it an excellent companion to many other hardy annuals and mixed seasonal plantings. Hanging baskets are another good use for Alyssum. The shallow root system will tolerate the cramped conditions of a basket through the whole growing season. Regular fertilizing with liquid seaweed or other liquid fertilizers made for blooming plants is a must. Feed containers every 2-3 weeks, and Alyssum will bloom until the first frost.
Winter Care for Alyssum
Alyssum that is grown as an annual requires little winter care. These plants will die back at the first nip of frost in the fall. Perennial plants will start new growth as the cooler fall weather arrives. Cut back plants to 4-6 inches from the ground, fertilize lightly and resume watering when the nighttime temperatures exceed 45 F.
Common Questions About Alyssum
Are Alyssum Deer Resistant?
Are Alyssum Poisonous?
Are Alyssum Edible?
Are Alyssum Invasive?
Why Aren’t Alyssum Blooming?
Does Alyssum spread
Is Alyssum invasive?
does Alyssum have invasive roots
Is Alyssum an annual or perennial
Does Alyssum come back every year
Alyssum leaves turning yellow, brown, black.
Alyssum growth rate?
Are Alyssum drought tolerant?
Have a question about Alyssum? Fill out the form below and we will try and get back to your question as soon as possible. We may even feature your question in this article to help other gardeners!
This page contains affiliate links to products on Amazon. We may receive a commission for purchases made through these links.
Author Robbin Small - Published 9-18-2022