Sweet William, Dianthus barbatus, is an old favourite cottage garden plant that is still popular today. It has a wonderful fragrance as well as colour, performs well in the garden and is listed as being perfect for pollinators. Unfortunately, in my view, recent developments have tended towards cultivars that are short and dumpy, and flower as annuals in mid and late summer – a time of year when we have so many other annuals.
Fortunately it is not all bad, new plants in the Sweet Series have retained the classic character of Sweet William.
At 50-80cm (20-31in) the plants are taller than many recent introductions making them ideal in mixed borders or as cut flowers, plus they still have a captivating scent.
Sweet William ‘Sweet Pink’, has full heads of neatly frilled flowers in pale rose pink, darkening as the flowers mature. The equally frilly, ‘Sweet Pink Magic’ (right) has flowers that open pure white and then mature though pale pink to deep rose, all the shades peaking harmoniously together. Look out too for ‘Sweets Mix’, a collection of these two new colours, along with the elegant ‘Sweet White’.
Sweet William are a hardy biennial, flowering the year after they are sown. The traditional and best time to sow seeds is May and June, their performance in late spring the following year is stupendous.
It is also possible to buy bare-root plants in the autumn, which can be planted outside between September and November. Bare-root plants will usually flower earlier than seeds sown the previous year.
** Please note the contents of this blog reflect the views of its author and are not necessarily those of the RHS **