STARS OF THE GARDEN
Although evergreen shrubs are the backbone of the garden giving you colour and structure in the winter, deciduous shrubs and perennials provide the seasonal colour. Most deciduous shrubs flower in the spring and early summer but some, such as Buddleia, hydrangea and Caryopteris flower later in the year.
Perennials are the showy stars of the garden and come in all shapes and sizes. Some are hardy and some need winter protection; some die down completely in the winter and return again in the spring and some – the woody perennials remain as evergreen plants during the winter. Penstemons and Geranium macrorrhizum are like this.
Every 3 years or so, in either spring or autumn, many perennials need to be divided into smaller clumps. This helps to control their size and also keeps them healthy. Overcrowded perennials often have fewer and smaller flowers and may often appear quite stunted. Another advantage of dividing up the plant is to make even more plants – and if you don’t want them, there’s always someone who will. Or you could grow them on and bring them to the annual Gardening Club plant sale in May.
Perennials such as Penstemons don’t die down in the winter and it is advisable to leave a good amount of top growth on the plant until quite late in the spring (when danger of frost has passed). Then you can prune the plant quite hard almost back to the base and it will re-sprout with nice new healthy growth. The same applies to Verbena bonariensis – leave some of the top growth on to protect the plant from frosts and then give it a prune in the spring.
Geraniums are devils for becoming huge and overcrowding other plants in the border and definitely benefit from dividing up. There is a lovely herbaceous geranium called Rozanne but it does grow into quite a large clump. It is worth trying to find a spot for it as it has pretty blue flowers all summer and into the autumn. Oriental poppies can become a bit over-large and definitely benefit from dividing up every few years.
Tall perennials such as delphiniums and Eremurus (foxtail lilies) do well at the back of the border, but some other tall plants can be placed in the middle of the border so that you have to ‘look through them’. Foxgloves, Verbena bonariensis and Knautia macedonica all look good when planted in small groups in the middle of the border. I saw a lovely display once of deep red dahlias with purple Verbena bonariensis growing amongst the dahlias.
If you plan what plants you want to put in your border you can achieve colour and interest for every month of the year either with different textures created by foliage or flowers. For example Hellebores are great for late winter colour, along with snowdrops and wood anemones; aquilegias, foxgloves and early flowering geraniums give you spring colour; dianthus (Pinks), astrantia, lupins, delphiniums and many others are good for summer interest; and late summer sees Penstemons, agapanthus, rudbeckia coming into their own.