Most annuals are showy and demand attention. They can be criticised for not being good ‘mixers’ with perennials and shrubs (not that I would always agree), but there are exceptions. Blue woodruff (Asperula orientalis or Asperula azurea) is a notable exception. The name might suggest that this is Asian in origin but it was only from the ‘orient’ from a European perspective and is from Turkey and lands to the east of there, not China. Asperula means ‘rough’.

Asperula is very closely related to galium which includes the awful weed ‘cleavers’ or ‘stickyweed’ and the perennial sweet woodruff. The flowers are small with four petals and a short tube. Blue woodruff is a delightful annual with narrow leaves and masses of blue flowers in clusters. It is a hardy annual and may self-seed. I am not sure if seedlings will overwinter if they germinate in autumn. I grew the plants by sowing in cell trays in March and they were very scrawny when I planted them out but they slowly spread and started blooming fairly quickly. The seeds did not germinate very quickly – they took almost a month to show signs of life but they were in an unheated greenhouse so perhaps they needed more heat.

Unusually for an annual, blue woodruff can tolerate some shade and they are fragrant. Well, that is what references say and, having just checked, they do have some fragrance but it is not strong. But it may be stronger in the evening. I would not grow these for their scent alone. It is also supposed to dislike excessive heat so perhaps my plants, which were struggling last week, were not up to the task of pumping out perfume. It is supposed to attract butterflies but so far they seem obsessed by the buddleias.

Although the leaves look decidedly like cleavers they are smooth and not ‘grabby’ and the plants make diffuse, neat mounds. My plants are about 20cm high which is what I expected. It would look lovely with dianthus and other grey foliage and I have some around a floppy pink alstroemeria though it looks perfectly OK with these marigolds. In theory this should self seed but I will try to collect some seeds just in case it doesn’t. If it seeded about around and under various shrubs I would be quite happy.

asperula orientalis, blue woodruff, how to grow blue woodruff