Bidens heterophylla

Bidens heterophylla is a perennial that forms a large bush (100-150cm (39-59in)) filled with a multitude of small bicolour flowers from July to October. Their colours are both soft and vibrant: white, pale yellow, and lemon yellow with a more intense centre, leaning towards ochre.

Its cousin, Bidens ferulifolia, is well known for taking centre stage as an annual in our summer compositions. Like it, Bidens heterophylla a has ramified, upright, and running stems (preferably in sandy soil) that originate from its base and grow in all directions. Its dark green foliage is finely and subtly cut. Bidens heterophylla provides a substantial base for slightly taller neighbours and occupies a generous volume. This cluster of stems is covered in small flowers (3 to 4cm (1 to 2in)), composed of five white ligulate petals at the ends and pale yellow streaked with lemon yellow as you approach the centre. The centre is also yellow, but darker.

Its Mexican origin suggests a sensitivity to cold, but it is not as significant as that. Our climates will suit it as long as it is given a warm spot, although it should not be exposed to drought. It is advisable to protect it in winter if the frost is intense (beyond -15°C (5°F)). Its withered stems will already provide some protection if you leave them in place.

Bidens heterophylla has an interesting habit and therefore easily finds its place in the middle or back of a bed. It helps structure colourful ensembles by keeping company with tall summer plants such as Helianthus, Solidagos, and Dahlias, and serves as a background for Heucheras and perennial geraniums. If you're looking to quickly add volume, don't hesitate.