PLANT YOUR BORDER
To conjure the most generous display, these plants need a sunny site on well-drained but moisture-retentive soil. Although artemisia thrives in really welldrained conditions while the carex is happier on wetter ground, they should all rub along amicably enough on any good soil improved with well-rotted organic matter. After planting, cover the entire border in a thick mulch of weed-free compost to smother annual weeds, retain moisture, feed soil fauna and continue to improve its structure.
1 Start autumn planting
Miscanthus establishes well from an autumn planting when the ground is still warm but damp from recent rains. It will eventually make a substantial plant so be sure to give it enough space to shine. Add further compost to the planting hole and tease out congested roots with your fingers. Firm and water in well to settle the soil and finish with a mulch of weed-free compost. Leave the foliage and flowers to bleach and stand as winter interest, only cutting back in spring once new shoots start to emerge. Large clumps can be divided in autumn or spring with a sharp spade or even an axe.
2 Sow the verbena in late winter
A brilliant hard-working perennial, Verbena bonariensis will flower in its first year. Start seed in late winter to early spring under cover, pinch out young plants to encourage bushy growth and plant into a sunny well-drained spot. On clay soil they may struggle to survive winter but they’re reliable on lighter ground where they tend to self sow. Add extra grit to the planting hole if in doubt. Leave the stems to stand overwinter, cutting back to low buds once growth is under way in spring.
3 Plant the carex and artemisia
Both these plants are best established in spring. When you plant the carex, add plenty of compost to its planting hole and water really thoroughly for the first year while it’s getting established. Leave the seedheads for their distinctive winter shape, then tidy up plants in spring. Once you have a sizeable clump, lift and divide in late spring, remembering to water well while they put their roots down.
Add extra grit to the artemisia’s planting hole and make sure nearby plants won’t overshadow it. It will flower in late summer but you may choose to cut off the shoots to emphasise the foliage instead. Cut back plants to the base in late autumn (‘Silver Queen’ is herbaceous, not evergreen) and finish with a mulch; new growth appears the following spring. Lift and divide this rhizomatous perennial in spring or take semi-ripe cuttings in late summer.
4 Finish planting after the frosts
The helichrysum and pennisetum are best planted after all risk of frost, placing them along the border edge where you can brush past their soft flowers or aromatic foliage. Neither is reliably hardy so, unless you live in a sheltered part of the country with well-drained soil, it’s worth overwintering them in a frost-free greenhouse, watering sparingly.
Helichrysum is, however, readily available as hanging basket plug plants, so you could just replace them each spring.
If you split your greenhouse pennisetums into smaller sections once the weather begins to warm, you’ll have multiple young plants ready to go out after all risk of frost. ✿