All Our Yesterdays: Christopher Lloyd on keeping colour in borders
Christopher Lloyd explains how he groups plants in his border for long-lasting colour
ONE of the greatest arts in gardening is the management of an important border so that it looks colourful, interesting and presentable over as long a season as possible. It is not easy and you will never be wholly successful, but it is a fascinating exercise and an absorbing challenge.
Often you can combine two different plants in the same grouping. For instance, bulbs among herbaceous perennials, such as tulips with Aster x
frikartii. This aster is a boon. Unlike the general run of Michaelmas daisies, which flower for a mere fortnight in September, Aster x frikartii gets going with its large lavender daisies in early August and keeps it up for two months.
Alluring alliums
Alliums or ornamental onions do well among certain low shrubs and perennials, too. The grey-leaved
Senecio cineraria ‘White Diamond’ has to be cut hard back each April. You can take advantage of its ensuing nakedness by interplanting it with
Allium ostrowskianum [A. oreophilum], with bright-pink umbels in May and
June. I also grow the pure-white
A. neapolitanum, which has a similar season, among the purple-leaved procumbent Sedum [Hylotelephium]
‘Ruby Glow’.
About the end of June, when it has finished flowering, the allium’s leaves and stems can all be grabbed in a large fistful and pulled out, leaving the field clear for the sedum’s late-summer season. The allium returns to life in autumn and is green all winter, when the sedum is dormant.
Gladioli and phlox
The hardy Gladiolus communis subsp. byzantinus, with slenderly graceful magenta spikes to 3ft (90cm) in June, is good among lower-growing phloxes, such as the white Phlox paniculata ‘Mia Ruys’. Again, you can pull out the dying stalks of the gladiolus as the phlox takes over. My Perovskia atriplicifolia, too, is underplanted with this gladiolus. The shrub is hard-pruned in spring, but is ready to take over, with its blue-flowered spires, from July onwards.
Clematis are excellent combiners. Every mature shrub in your garden should be given a clematis to grow through it and double up on the season of interest and colour. Thus I have the purple C. ‘Jackmanii’ growing through the yellow July-flowering Mount Etna broom (Genista aetnensis). Their seasons overlap, making a sumptuous purple and gold tapestry, but the clematis continues in flower for more than a month afterwards.
Second crop
Some perennials, like the red monardas, just give you one splash of colour for a limited season, and that’s it. You
deadhead them for the sake of neatness, but nothing more happens. Others, if deadheaded, will produce a second crop, especially freely if the autumn is warm and sunny.
Border phloxes often oblige in this way. Not all of them, but most, if they are well fed and growing strongly – not if they are short of water and overcrowded. Just remove the flowered panicle as it is fading, and side growths near the top of the stem will take over. A July-flowering helenium like ‘Moerheim Beauty’ will carry an excellent autumn crop if deadheaded and its bronze-colour looks well with the purple spikes of Salvia x superba, which behaves and should be treated in the same way.
Continuous season
Certain perennials do, by nature, have an extraordinarily long and continuous season with practically no assistance from the gardener. Good examples are the cranesbills, or hardy geraniums, like the magenta G. sanguineum or the bright pink-mauve G. endressii. They start in May and continue until October. Verbena bonariensis gets going in July, but thereafter improves steadily until late autumn. It is a stiff six-footer [1.8m] requiring no staking, covered with purple blossom and with late butterflies.
A rotation of annuals with biennials is another good idea. Make a bolder patch in your border of sweet Williams, Canterbury bells or – if your soil is light – Brompton stocks in the autumn and interplant them with tulips.
Late in July lift the whole lot, harvesting your bulbs and discarding the biennials, and replace with an annual like Heliotropium arborescens ‘Marine’ or dwarf bedding dahlias treated as annuals, sown in May and brought on in individual 5in [13cm] pots for July planting.