Honesty, Lunaria annua, with Golden Hop

Honesty, Lunaria annua, is in flower in the garden at the moment. It has long been one of my favourite plants and with its cheerful pinky-purple flowers it looks especially good in the semi-shade by our blue shed, next to a Golden Hop (Humulus lupulus ‘Aureus’).

Honesty is a biennial plant that has been naturalised in most temperate parts of the world, though it originally comes from the Balkans and south-west Asia. Once established, it will self-seed but it is very easy pull up seedlings that are growing in the wrong place, or you can move them early in the year before they develop their long tap root. It loves semi-shade and often prefers to grow at the base of hedges, rather like its relative Garlic Mustard (‘Jack-by-the-Hedge’).

It is also possible to treat Honesty as an annual, if you sow the seed very early in the year, but the resulting plants will never have the stature of slower grown specimens.

Honesty can sometimes take longer to reach flowering size. I bought my seeds from Great Dixter Gardens in April 2013 and sowed them in the early autumn of that year. I planted them out in the early spring last year but they grew rather slowly and this is the first year that they have flowered. My soil is rather dry, which may account for the slow growth.

My plants will set seed this summer and the plants will die. The seeds are borne inside architectural flat seed pods and these provide interest for the remainder of the year after flowering, or can be used for winter dried flower arrangements. The flowers can be attractive to butterflies too.

Honesty is a member of the cabbage family, the Brassicaceae. Its seed pods (known as sillicles) have an outer skin, which falls off (or can be peeled off) when dry to reveal a silvery central membrane to which the seeds are attached.

These seed pods give the plant many of its names. ‘Honesty’ probably comes from the transparency of the central membrane and ‘Money Plant’, ‘Silver Dollars’ and ‘Chinese Money’ refer to the coin shaped pods. In Denmark the plant is called judaspenge and in Dutch the name is judaspenning (coins of Judas). Both names refer to Judas’ thirty pieces of silver in The Bible. The French name is monnaie du pape (Pope’s money). Lunaria means moon-shaped – another reference to the seed pods. Van Gogh included the seed pods in his 1884 painting ‘Vase with Honesty‘.

Another, more prosaic name is ‘Annual Honesty’, which distinguishes Honesty from Perennial Honesty, Lunaria rediviva. This is a very pretty, clump-forming perennial which also flowers in the spring but has paler, scented flowers and less spectacular seed pods. I bought a specimen from West Acre Gardens earlier this month. It likes slightly damper soil than Lunaria annua. I’ve planted it in semi-shade and have improved my sandy soil with compost, to help it thrive.

Honesty seeds can be used as a mustard substitute as the plant contains sinigrin, a compound that is converted into mustard oil (allyl isothiocyanate) when the plant is crushed.

There are some fancier strains of Honesty, such as Lunaria annua ‘Variegata’ (white flowers, marbled foliage) and Lunaria annua ‘Albiflora’ (white flowers, green leaves), but I’m happy with the normal flower and leaf colours.

Honesty with seed pods, mid May.