Sweet Williams are a hardy flower that come in shades of red, white, purple and pink. With serrated five-petalled blooms, that are similar in appearance to Carnations, these flowers are ideal for cottage gardens. 

Loved by moths, butterflies and bees for their bright colours, Sweet Williams are sweetly scented flowers. They can be easily grown in pots, making them an ideal choice for smaller gardens.

When do Sweet Williams flower?

You’ll see the pretty serrated edged petals in late spring to early summer, blooming throughout the season, with continual deadheading. Sweet Williams can be sown as late as July but keep in mind that they may not bloom that year. 

Commonly asked questions

What’s the difference between Sweet Williams and Dianthus?

Sweet Williams are part of the dianthus family but the main difference is the type of plant they are. Dianthus plants are either annual or perennial but Sweet Williams are biennials or perennials. 

Wild Sweet Williams are known as phlox; they don’t grow as high as Sweet Williams and are a shade loving plant.

Are Sweet Williams perennials?

Yes! Sweet Williams are perennials meaning they’ll return every year to adorn your garden with colour.

How tall do Sweet Williams grow?

Sweet Williams grow up to 45cm tall, perfect for the back to middle of your border. Give planting them amongst hollyhocks a try – having taller flowers behind them will create a stunning impactful display. 

Planting and Growing Advice

How to plant Sweet Williams?

One of the great things about Sweet Williams is that they can be planted straight into the ground or into a container. To plant, firstly remove any weeds from the soil to prepare the ground for planting. Rake the soil ‘til it’s fine before planting the seeds in soil. Plant your seeds 5mm down, spaced about 30cm apart after watering the soil. 

Where to plant Sweet Williams?

Plant your Sweet Williams in full sun for the more frequent flowering blooms but rest assured they will tolerate partial or dappled shade. The plants are ideal for borders or beds and pair well with other flowers such as geraniums, petunias, pansies, verbena, salvia and sweet peas.

When to plant Sweet Williams?

The short answer is: it depends on their size. Are you planting from seed? Are you planting them outdoors or indoors? This also depends on when you can plant them. You can plant them as seeds nearing the end of spring or early summer. The seeds can go straight into the ground but if you really want to see flowers this year you’re better off buying a plug plant. The plug plants can be planted outside in either autumn or late spring. 

Why have my Sweet Williams not flowered?

If your Sweet Williams have not flowered, you don’t need to worry about wasting your money on plants that don’t bloom. It normally means they have been sown too late or the weather is poor and they will bloom instead next year. To encourage further growth, be sure to cut off any dead flowers. In prolonged dry periods or heatwaves make sure you give your plants enough water.

How many times do Sweet Williams bloom?

Less hardy Sweet Williams will flower in their second year, however hardier flowers bloom year after year. Seasonally, their flowering period is between May through to October and most will continuously bloom throughout this period as long as they’re looked after properly with regular deadheading and watering.

Can you take cuttings from Sweet Williams?

Yes, you can take cuttings from Sweet Williams. Sweet Williams are very easy to propagate and this is a great way to ensure that you’re able to have more next year without any extra cost. The best time to take cuttings from your plants is June and you should take a whole “branch” – new growths on the side of the plant, and you can just snip this right off. Remove all the leaves about 2.5-5 cm from the bottom. Dip the end of the cutting in a rooting compound and plant in a small plant pot with regular soil and keep regularly misting. 

How to care for Sweet Williams?

• Fertiliser: Sweet Williams should be fed with an all purpose fertiliser every couple of months during the growing season. 
• Watering: Sweet Williams are fairly simple plants and will only need watering in periods of long dry spells and heatwaves. 
• Winter Care: Once the leaves have died back apply a 6 inch layer of mulch around the plant packed loosely.

How to prune Sweet Williams?

Aside from deadheading, Sweet Williams won’t need much pruning in their first two years but they may start to grow unruly in their third year. Prune your plants in the autumn or early spring, trimming larger stems near the base.

How to stop slugs eating your Sweet Williams?

The most effective and non-invasive way to keep slugs at bay is to pick them off by hand. It’s best to do this either early in the morning or in the dark evenings as that’s when the slugs go out to feast. If you don’t fancy that though (we don’t blame you!) check out our slug repellent products that can help to keep them at bay.