In any garden there are star plants that demand our attention through their striking colour, height or shape. They stand out from the crowd and their star status is apparent. Yet, not every plant in the border can be quite so showy. If you have too many stars, then their impact will get simply lost in the crowd, and this is where filler plants come into their own. Often understated, often overlooked, but oh-soessential for a beautiful border, complementing the stand-out others. I particularly like filler plants that are light and airy, that hold their blooms high above the foliage, and if they have feathery foliage too, I like them even more.
Just because they are filler plants, doesn’t mean that they aren’t beautiful in their own right, but they are usually more subtle or muted, with a multitude of tiny flowers rather than fewer large ones. Repeat planting of your chosen filler plants across your garden bed will add a sense of cohesion and help to draw the eye across the planting scheme overall. Here are some of my favourites:
Thalictrum
The leaves of thalictrum remind me of aquilegia, but the flowers are very different. Thalictrum produce a pompom of fine fluffy flowers on tall stems and come in shades of purple to pink, through to white and yellow. Most varieties are happy in partial and light shade. I spotted Thalictrum ‘Black Stockings’ in the Forest Bathing Garden at RHS Chelsea Flower Show.
These lovely plants are available in a variety of heights, from the 160cm (5ft) tall Thalictrum rochebruneanum (which I’ve recently bought to grow towards the back of a border), to the diminutive Thalictrum kiusianum at 10-15cm (4-6in) tall. There are taller varieties, but I’m less inclined to think of those as filler plants and more as statement plants in their own right.
Anthriscus sylvestris ‘Ravenswing’
This variety of cow parsley offers a great foil to more pale-leaved plants, plus a mass of frothy white flowers. They do a good job of filling a space without overpowering it and enable other plants to grow up and through their stems. Similar in habit, Anthriscus sylvestris ‘Golden Fleece’ has light green leaves to add a splash of brightness to an area. It is easy to grow from seed and will readily self-sow in the garden. However, it is also easy to remove any unwanted plants when they are young.
Verbena bonariensis
An instantly recognisable verbena that became much-used by garden designers to add height and volume to borders. And it is popular for good reason, as it grows easily from seed and attracts pollinators to the garden. Weed out unwanted seedlings in the spring. To av
