We are well into summer now and the lush abundance of colour scent and foliage is everywhere. Foxgloves (Digitalis), are an early to mid-summer biennial, which make a welcome addition to any informal border. They put on leaf in the first year of growth and flower the following year, producing mauve-purple spires which produce masses of seed. They generally die after going to seed, and, as their seed is very small, they may or may not come up again from seed the following year. Rather like poppies, if the small seeds get buried they won’t come up, but they do last a long time in the soil, so if you disturb the soil one year, you can be unexpectedly blessed with a mass of foxgloves, as long as you are careful not to weed them out as seedlings.
If you want a more reliable method of ensuring you have foxgloves in the garden, you can sow seeds in seed trays or flowerpots.
Foxgloves need a period of winter cold (vernalisation) at the end of their first year, in order to flower successfully the following year. Their flowers open at the bottom of the stem first, opening gradually up the stem, and go to seed in the same way, so that by July you often have just a few flowers left open right at the top of the stem. This ensures a longer season of bloom and pollination.
Pictured above is the native wild foxglove Digitalis purpurea, which to my mind is the most attractive. However there are more unusual, cultivated or species foxgloves available, including the white flowered Digitalis puurpurea f. albiflora, the short-lived perennial foxglove Digitalis laevigata, Digitalis lutea, a smaller yellow foxglove, and Digitalis ferruginea with its rusty coloured blooms.
When considering the design of a border, garden designers look at different plant shapes for interest.
A foxglove is a spire shape, which contrasts with a more soft, dome-type shape of a hardy geranium, for instance or the firmer dome shape of a clipped box, the sperical blooms of Alliums or Echinops (globe thistle), the flat flowerheads of Achillea, or the feathery foliage of fennel (Foeniculum vulgare), ornamental grasses or ferns, or the spikey shapes of Yuccas, Phormiums and Cordylines. Contrast in shape and texture always adds interest to a border, and should be given equal consideration to colour-scheme (see the sketch on the right).
Spire shapes are one way of giving height, punctuation and drama to the herbaceous border. Other spire-shaped plants and flowers include:
- Foxtail lilies (Eremurus)
- Kniphofia (Red hot pokers)
- Veronica spicata
- Hollyhocks (Alcea)
- Teasel (Dipsacus)
- Rosebay willowherb (Chamerion angustifolium)
The more structural, permanent spire or cone shapes of various conifers, can also be useful.
These are not restful shapes, they can add formality to a garden, and act as an exclamation mark or focal point, drawing attention. As in the sketch on the right.
Conifers used in this way include:
- Taxus baccata ‘fastigiata’
- Juniperis communis ‘Gold Cone’
- Juniperis scropulorum ‘Skyrocket’
- Juniperis chinensis ‘Obelisk’
- Chamaecyparis lawsoniana ‘Columnaris’
- Cupressus sempervirons ‘Stricta’
I have also seen clipped beech used successfully as a column to punctuate an otherwise informal, herbaceous planting. These shapes are to be used carefully with consideration to the impact they have. Whereas, foxgloves can be used in a more carefree manner, allowing them to self seed at will.