IfPart of the Lobulara genus they are a relatively small plant that is often grown as annuals. Typically reaching heights of 3 - 12 inches (7 - 30cm) they're often used as "edging" plants due to their small height. Indigenous to the Mediterranean Sweet Alyssum can be grown with relative ease in all regions of North America (zones 7-10 perennial in warmer regions or grown as annuals in colder regions).
Blooming in a small variety of colors including white, pink or purple - they are more often known for the honey-like fragrance they produce all season long. Flowers of the Sweet Alyssum tend to grow in clusters and the white variety of Sweet Alyssum are often referred to as "Snowdrift".
Sweet Alyssum seeds are strong, hearty and easy to grow. Most gardeners choose one of two common methods to produce them: sowing them outdoors or starting them indoors.
If you intend to grow your Sweet Alyssum outdoors then sow the seeds on the ground as soon as the last frost has left the soil in early spring . Sweet Alyssum has a flexible growth pattern growing well in either sunny or partially shaded areas (full sun preferred) where the soil is rich and moist. Plants should bloom in a little less than 6 weeks.
If you prefer to start off growing your Sweet Alyssum indoors you should start approximately 8 weeks in advance. Your seedlings will require plenty of light and a relatively constant temperature between 54 - 70 degrees Fahrenheit (12 - 21 degrees Celsius) in order to germinate properly. The germinating process typically takes 1-2 weeks.
Sweet Alyssum Growing Tip #1
Before planting clear the area you intend to plant. Turn the soil several inches deep making note that in heavy clay or poor sandy soils you should consider adding aged compost to aid in drainage and add nutrients. The Sweet Alyssum should be transplanted about 6 - 8 inches (15 - 20cm) apart. Note this plant requires water regularly (about every other day and up to twice a day in very hot climates)!
Sweet Alyssum Growing Tip #2
To force Sweet Alyssum into successive blooms, cut the plants back at regular intervals after which the plants will be induced into producing a somewhat constant set of blooms. Removing spent flowers will also foster plant hardiness and increased bloom activity.
Sweet Alyssum Growing Tip #3
There is (generally) no need to fertilize Sweet Alyssum. If the plants become slow in their production of blooms, cut the plants back by about half and they'll grow back quickly and start blooming again within a few weeks.
Sweet Alyssums make great container or hanging plants because of how they spill over the edges and flower creating a soft frothy look. Regular watering aside, they're ideal for the "lazy" gardener because they self seed as the plants cycle. As such, these plants make a great addition to your backyard oasis.
You may purchase Sweet Alyssum seeds throughout the year from a variety of vendors both local and online. As there are quite a few sub-varieties of Sweet Alyssum and some are more demanding than others - make sure you understand the specific type of Sweet Alyssum you're getting!