Pro advice to grow sweet alyssum

A dainty, undemanding little plant like sweet alyssum is just what every gardener needs to edge a bed, fill a bare spot or serve as an accent. Here are the facts about the plant and the best way to grow it.

Sweet alyssum is a great choice whether you want to add a dash of colour around the edge of a container or carpet a broad swath of the garden with a reliable, durable bloomer. this short, dense, mounding plant adds lacy texture to hanging baskets, fills the crevices of rock walls or creates a colourful hem for paths.  It's smothered by so many honey-scented flowers throughout the summer that you can't see its needle-like leaves. It also works as a magnet for nectar-seeking butterflies. In Zone 9, sweet alyssum can also be sown in autumn for winter performance.

Sweet alyssum's dimensions are discreet. Each plant stands less than 15 centimetres (six inches) tall with a 30 centimetre (12 inch) spread. Despite this small stature, few sights compare with the ground-hugging sea of blossoms in white, pink, rose and lavender that result if you plant Easter Basket mix, a hybrid that stays compact even in the heat of summer. If you plant the pearly 'Wonderland White', your garden will look as though it's been blanketed by a blizzard in July. Combine this small wonder with petunias, herbs, lady's mantle or annual geraniums, and you can't fail to make a garden statement.

Bedding plants are available at garden centres in spring, but sweet alyssum is very easily grown from seeds sown in the garden. Here are the basics:

• Two weeks before the last spring frost simply scatter the seeds thinly on the ground, rake lightly to cover them and water the soil gently.
• Seeds germinate quickly and should be thinned to 12 centimetres (5 inches) apart.
• In only six weeks you'll begin to see flowers.
• It's a good idea to keep a container of white-flowered sweet alyssum seedlings on standby. If you need fillers for containers or beds, simply cut out a brownie-sized chunk of alyssum and drop it into place.

Sweet alyssum loves full sun, and fertile, well-drained soil. However, this plant tolerates conditions that are considerably less than ideal without complaining. Overwatering is its primary stumbling block, as soggy soil can lead to fatal root rot, so water plants only when the soil becomes dry. Where summers are long, older varieties in particular benefit from shearing back in midsummer to prolong flowering. Use shears or a string trimmer to clip the plants back to half their height. Drench them with a balanced, water-soluble fertilizer and look forward to strong growth and flowering as cool nights approach.

Sweet alyssum, while virtually trouble free, is prone to minute spider-like pests called spider mites. They most often attack during the hot, dry weather of late summer.

• You will know they've arrived when leaves have a pale, stippled appearance, caused by feeding pests. You will also see fine webs on the leaf undersides.
• Apply a forceful spray of water from a hose every other day until the infestation subsides.

In late summer when days are warm and humid and nights are cool, powdery mildew, a fungal disease, can settle in, coating leaves with a white powder that won't rub off and weakens the plants. Cutting the plants back and allowing healthy foliage to appear is an easy and effective control.

Sweet alyssum doesn't give up easily and can take on the toughest assignments in the flower garden.  Put them to the test in your own garden and love the results.