Make an impression with plants to edge a border
What grows at the front needs to impress!
When it comes to choosing plants to fill a space, many things should be considered. One of these is where the plant is to be placed. It’s very difficult to select plants in isolation as they need to correspond with one another for an eyepleasing display. I like to select plants for the front of a border first and work backwards. Another reason is so I don’t run out of space, which often happens if I work from the back to the front.
The plants that edge a border need to look good for much of the year. They also shouldn’t take the glamour away from other plants further back, and they should be short so they don’t hide the plants growing behind them.
Some of the best perennials for edging create thick, leafy carpets that in time will exclude unwanted weeds.
Persicaria affinis ‘Superba’ (bistort) is a perfect front-of-border plant, with short pokers of white and red flowers and slender stems of small leaves that turn shades of red in autumn. Another lovely carpeting plant is sanguisorba ‘Tanna’, which carries the small, sculptural, red flowers above a thick mat of pretty little leaves. Stachys byzantina (lamb’s ears) is a must as the thick, felt-like leaves grow into a textural carpet of silver that blends easily with anything. If the tall, silver stems of flowers aren’t to your liking choose S. byzantina ‘Silver Carpet’ as it rarely blooms. A great evergreen edger is
neat-growing, distinctly old-fashioned Saxifraga
urbium (London pride) with slender stems of tiny pink flowers and midgreen leaves. The leaves of heuchera (coral flower) come in many colours, but my favourites are those with chocolatebrown foliage and ones that produce lots of flowers. They don’t spread, but grow into tidy hummocks from which slender flower stems spring bearing tiny, bell-shaped blooms. To get a good display grow at least three plants together, perhaps more.
Clever catmint!
Some of the perennials I use for edging can be categorised as flowery yet they’re still modest enough not to take any of the glamour away from more showy perennials behind them. Nepeta (catmint) fills this slot. The long stems of tiny blue and white flowers and scented, grey-green leaves create frothy clumps loved by bees. Some varieties, such as nepeta ‘Six Hills Giant’, get quite large so I cut the clump back twice during the growing season. The initial trim is to remove some of the lower stems that grow under the clump to stop them lying on the lawn and killing the grass. Later, as the first flush of flowers is fading, I cut the whole plant back to get more flowers and create a neater mound. The one problem with nepeta is cats love it. My cats go into a rolling frenzy on top of the clump, squashing it flat. If you have this problem and don’t want it, grow calamintha, which is ignored by cats. Although it flowers later it will give the same frothy effect.
Add some drama
If you want something a little more dramatic in the way of flowers, the many varieties of Geranium sanguineum are a good choice, particularly as they tolerate a certain amount of shade and can be grown next to more bushy perennials that might compete for light. This isn’t the case with sun-loving, silver-leaved Anthemis punctata cupaniana, which is a great plant for tumbling over a wall, as is the alpine form of the florist’s ‘gyp’ gypsophila ‘Rosenschleier’ (baby’s breath), as its clouds of tiny flowers are perfect for hiding edges. Alpine plants can be good for edging because they’re small, but most are also fussy about location, needing a very welldrained soil. Colourful helianthemum (rock roses) are more tolerant of soils that don’t drain immediately and they’re great for softening the edges of hard paving. Another great edge softener is generous-flowering Erigeron karvinskianus
(fleabane), that has a reputation of seeding freely around. I’ve found this isn’t the case, unlike Alchemilla mollis (lady’s mantle), which is one of the best all-round perennials. I love this plant not only because it’s easy to grow in almost any situation and covers the ground, but because the frothy stems of tiny lime-green flowers are great for cutting.