Fillers – the unsung heroes of the herbaceous border
When you plan your herbaceous border, you may think first of spectacular lead plants or pretty companion plants. But do you know who really holds the border together? The filler perennials! They are the charming space fillers that provide richness, structure and a harmonious overall look.
You will realise how important fillers are when you discover bare spots in your border. Then it’s time to look at what are known as filler perennials.
What are fillers plants?
Filler perennials grow loosely between larger plants, hiding bare spots and tying the ‘stars’ of the border together. They make your border more vibrant and easy to maintain by suppressing weeds and protecting the soil.
Here are some ideas for filling perennials for your border:
Lady’s mantle (Alchemilla mollis)
Lady’s mantle is a real gap filler with its soft, round leaves and yellow-green flowers. The flowers can also be used in bouquets. Lady’s mantle has another special feature. Raindrops stay on the leaves, which looks lovely.
Lady’s mantle grows well in most soils and tolerates sunny to half shade.
Waldsteinia (Waldsteinia ternata)
Waldsteinia is a hardy ground cover ideal for shady areas. The yellow flowers brighten up dark corners of the garden and the dense foliage keeps weeds at bay. Another advantage is that Waldsteinia is an evergreen ground cover
It thrives in shade and dry shade and prefers a well-drained, humus-rich soil.
Cranesbill (Geranium)
The geranium is an uncomplicated and floriferous perennial that can quickly fill in gaps in the border. There are many varieties that bloom in different colours such as blue, purple, pink, red or white.
Depending on the variety, geraniums thrive in both sun and shade and in a nutritious, well-drained soil.
Coral bells (Heuchera)
Coral bells adds structure to the garden with its colourful foliage. There are many varieties with different leaf colours. Cranesbill is mainly grown for its foliage rather than its flowers.
Heucheras need a partially shaded or shaded location and a fresh to moist, loose, humus-rich soil that does not dry out too much in summer.
Stonecrop (Sedum)
Sedum is a very popular autumn flowering perennial and a wonderful addition to flower beds. There are low-growing sedums and taller varieties, such as stonecrop (Sedum telephium) The pink clusters of flowers are a real magnet for bees. Don’t cut off the faded flowers in autumn, as they look very decorative throughout the winter.
Sedum prefers a sunny location with well-drained, dry, sandy or gravelly soil.
Thyme (Thymus)
Thyme is not a perennial, but as a sub-shrub, but it is very good as a filler. Wild thyme (Thymus praecox) or creeping thyme (Thymus serpyllum) forms dense mats and suppresses weeds. The pink or crimson flowers attract large numbers of bees.
Thyme grows in sunny places, needs well-drained, chalky soil and can withstand prolonged periods of drought.
🌸 Filler plants: annual flowers and self-sowers
If there are still gaps in your flower border, you can fill them with annual flowers. These grow quickly and flower profusely. It’s best to plant flowers that self-sow. This will save you time and money next year and you’ll have low-maintenance flowers that grow where they feel comfortable.
Ideas for annual flowers to fill gaps include: garden cosmos (Cosmos bipinnatus), marigolds (Calendula officinalis), common zinnia (Zinnia elegans), columbine (Aquilegia), foxgloves (Digitalis) or love-in-a-mist (Nigella damascena).