I love plants that flower in the winter, especially as so many of them have wonderful scent – and one of the best, but least known, is Coronilla valentina glauca. Producing clusters of small, pea-like flowers this shrubby plant is covered with bloom, usually from October to around March in my garden. And in some years it seems to flower on and off through much of the year.
The evergreen leaves are pretty too, with their filigreed shape and bluish-green hue. In fact I love the glaucous foliage so much that I tracked down a variety called ‘Brockhill Blue’ which seems to have a stronger blue colour than the species. In addition, most forms have a reddish colouration to the younger stems, particularly those exposed to strong sunlight, from late summer onwards.
But for something so lovely and of such value to the garden, this wonderful plant has not been blessed with the most endearing common names. ‘Bastard senna’, ‘scorpion vetch’, ‘sea green’ and ‘day-smelling coronilla’ are hardly inspiring are they?
Where should I plant coronilla
Coronilla will grow happily in any good garden soil though not on very heavy, wet clay soil as being waterlogged will kill the roots. It can however cope with free-draining, dry soil. Plants will grow in large containers of loam-based compost mix 4:1 (by volume) with sharp, horticultural grit.
Full sun is ideal for coronilla. This will help to ripen the stems thoroughly and promote the most abundant flowering. In shady positions the plants will tend to become leggy. They are great for growing trained on a south-facing wall or grown over an arch – something which I have done in my own garden. The foliage makes a great foil to grow climbers through it. I have used Eccremocarpus scaber through mine, as well as Clematis viticella – both of which bloom in summer, without swamping the coronilla.
Which is the best coronilla to grow
The straight species, Coronilla valentina glauca, is the most readily available form of the plant – although few garden centres stock any of them. This species has orange-yellow blooms which show up really well in the darker days of winter. As already mentioned, there are some selected forms of this plant which have a more intense blue colouration to the foliage.
There is also a more lemon-yellow flowered variety called C. valentina glauca ‘Citrina’. It is a softer shade, but I personally think it has less impact that the straight species. In addition there is a variegated form – C. valentina glauca ‘Variegata’. This may be visually appealing at close quarters, but the variegation can look jumbled together with the flowers.