THE idea in a herbaceous border is to create blocks of colour with different plants jumbled together to mature into intriguing collages of colour and texture. The secret is to pick plants that flower from early summer to late autumn.
Summer flowering bulbs such as lilies, canna, dahlias and gladioli can be used to produce splashes of colour at critical times during the summer. These bulbs can be planted directly into ground or left in pots and placed strategically in the border to create dramatic impact and to jazz up established perennial plantings.
First decide on the shape, size and position of the new bed. Choose an open sunny site and decide whether you will have a border or island bed. The island bed has the advantage that it is accessible from all sides. The tallest plants are placed in the centre of the island bed while they are placed at the back of a border bed. The shape of the bed will depend upon the shape of the garden, for a formal garden choose a rectangular, oval or circular shape. For the informal garden choose a border with free-flowing curved lines.
There is a hard and an easy way to prepare a bed for planting. The hard way is to dig the ground, remove all weeds and add in compost or well-rotted manure. The easy way is to spray the ground with a weed-killer, such as Roundup, which will kill the grass and the more persistent weeds. Another easy way to prepare the ground is to cover it with a layer of weed-block and then cover the weed-block with a layer of bark. Cut holes in the weed-block to place plants in the ground.
Selecting plants for the border
To produce continuous display of colour, choose plants that flower in spring through the summer into the autumn. Grouping at least three plants of the same kind together is more effective than having single plants dotted about everywhere. The following are just some of the plants you can choose for your herbaceous border:
Alstroemeria grows up to 3feet tall, funnel-shaped flowers in red, pink, white, yellow and orange in the summer. Asters or Michaelmas daisies flower in the autumn, producing daisy-like flowers in various colours. Astilbes produce plume-like flowers on stems 2-4 feet tall in a range of colours such as red, pink, purple and white from June to August. They need moist, humus-rich soil that does not dry out in summer. Campanula produces bell-shaped flowers on stems that vary from 6 inches up to 6 feet from mid-summer to early autumn. The flower colours are mostly blue, with a scattering of white and the occasional pink. Crocosmia (montbretia) is a bulbous plant that flowers from July to October on stems 2-3 feet tall. The trumpet shaped flowers vary in colour from burnt-orange, flame-red, orange and yellow. Dahlias will provide lots of colour in late summer. Dahlias can be grown from tubers or seeds. Delphiniums produce tall spires up to 6 feet tall in a range of colours that cover all three primary colours, although when we think of delphiniums we tend to think of blue, they flower in early summer. Dicentra is a graceful plant, growing 1-3 feet tall and it produces rose-pink or white heart-shaped flowers from late spring to early summer. Digitalis (foxglove) can grow up to 6 feet tall, producing white, yellow, pink flowers many of them richly spotted. Euphorbia are grown for the colour of their foliage, they produce a white sap which is highly poisonous. There are many geraniums that flower from mid-summer to mid-autumn. Lupins are one of the traditional flowers of the early border. Herbaceous peonies provide a reliable display of colour each year. Phlox is a plant that will fill the border with colour in late summer.
Polygonatum (Solomon’s seal), Rudbeckia, salvia, sedums, solidago and verbascum are other plants worth growing. Plant some foliage plants like acanthus, artichokes and melianthus major to give a distinctive sculptural shape to the bed.