Hardy florals

Sibling gardeners June and Jimi Blake select their top 10 summer-flowering perennials – all vigorous and pest-resistant – to lift any garden out of its midsummer doldrums, writes FIONNUALA FALLON

IT’S OFTEN BEEN said that the mark of a truly great gardener is one whose flower borders look as good in mid or late summer as they do in June. The trick to achieving this is using hard-working, garden-worthy plants that earn their keep by being hardy, vigorous, long-flowering and resistant to pests and disease. Nobody understands this better than sibling gardeners June and Jimi Blake, owners of two very different but equally outstanding gardens that lie within a stone’s throw of each other in west Wicklow.

So when I asked them to recommend 10 colourful perennials guaranteed to lift any garden out of its midsummer doldrums, I knew they’d both come up with some brilliant suggestions.

June’s top 10 summer-flowering perennials

Knautia macedonica

Hardy, rabbit-proof, slug proof, with vivid crimson flowers from late May to September, if regularly deadheaded. Likes: full sun, well drained, neutral to alkaline soil. June says: “Nip out the first flush of flower stems in early summer to create a bushier, sturdier plant.”

Lupin Band of Nobles Series

The Band of Nobles Series of lupins are vigorous plants with imposing spikes of scented flowers in a vivid range of colours. Likes: full sun, moist but well-drained soil. Height 120cm. June says: “Cut off flowering stems at the base once finished.”

Geranium ‘Rozanne’

Fantastically long-flowering, hardy, perennial geranium with lavender-blue flowers from June until September. Likes: full sun/partial shade, well-drained soil. Height 60cm. Deer-resistant. June says: “Not suitable for a small garden as each plant will reach the width of your outstretched arms. No need to dead-head as it’s sterile.”

Persicaria amplexicaulis ‘Firetail’ RHS AGM

Tall, large-leaved, clump-forming, herbaceous perennial, produces fiery red flower spikes throughout summer and into early autumn. Likes: sun/light shade, tolerant of most soil conditions. Rabbit-proof, slug-proof. Height 120cm. June says: “Great plant to grow from seed.”

Sanguisorba menziesii

Wine-red, fluffy “bottlebrush” flowers from late spring followed by ornamental seed-heads. Likes: full sun, partial shade and damp, fertile soil. June says: “Don’t deadhead as the seed-heads are very ornamental.”

Saxifraga stolonifera

Forms rosettes of evergreen foliage, produces a graceful cloud of exquisitely pretty, pale flowers throughout the summer months. Likes: deep shade, a moist soil. Height 20cm. June says: “Tough as nails. One for a very shady spot where nothing else will grow.”

Thalictrum lucidum

Tall, airy perennial with glossy, ferny leaves and powder-puff yellow flowers throughout the summer. Likes: Full sun, a moist but well-drained soil. Height: 120cm plus.

Nepeta ‘Six Hills Giant’

Silver-foliaged perennial that produces a haze of lavender-blue flowers throughout the summer months. Likes: full sun/partial shade and a damp but well-drained soil. Height 90cm. June says: “Cut back by half after first flowering to encourage a second flush.”

Astilbe rivularis

Copper-tinged, deeply divided foliage and vertical plumes of deep-purple flowers from mid-July until autumn. Likes: Full sun/partial shade, moist but well drained soil. Rabbit-proof and slug-proof. Height 150-180cm. June says: “This plant will self-seed when it’s happy. Great seed heads for the winter.

Persicaria ‘Red Dragon’

Grown not so much for its flowers but for its dramatic, maroon-coloured, lance-shaped leaves. Likes: Full sun/light shade, tolerant of most soil conditions. Height: 80cm. June says: “A brilliant foliage plant, but keep nipping out the stems to encourage bushiness. Propagate by cuttings.”

Jimi’s top 10 summer-flowering perennials

Geum ‘Prinses Juliana’

Produces a constant succession of vivid orange flowers from late April up to the first harsh autumn frosts. Likes: Full sun/ partial shade, moist but well-drained soil. Height 60cm. Jimi says: “Regularly dead-head spent flowers by carefully nipping back to just above next flower bud/leaf.”

Astrantia major ‘Bo-Ann’

Fantastically floriferous plant with the added bonus of being slug-proof. Powder-pink, starry flower bracts appear from late spring until early autumn. Likes: Full sun/light shade, a rich, moist soil. Average height 70cm. Jimi says:“Cut back the faded flower stems but not the foliage.” Geranium ‘Ann Thompson’ RHS AGM

Compact perennial geranium, which produces a multitude of black-eyed, cardinal-purple flowers from June until October. Likes: full sun, light shade, fertile, well-drained soil. Height 40cm. Jimi says: “Grow this plant in preference to the better-known Geranium ‘Ann Folkard’, which has a tendency to sprawl.”

Erysimum ‘Parrish’s’

Clump-forming, perennial wallflower with vibrant pink-purple flowers that appear from mid-spring to autumn. Likes: full sun, well drained neutral/alkaline soil. Height 90cm. Jimi says: "I first got this plant from Derry Watkin's nursery ( specialplants.net). It's easily propagated from cuttings."

Diascia personata

Many gardeners know diascias as low-growing bedding plants but this is something very different. Tall, surprisingly hardy and evergreen in a mildish winter, it produces dense clusters of pink flowers from early summer to late autumn. Likes: Full sun, well drained soil. Height 150cm-180cm. Jimi says: “Cuttings will strike very easily if placed in a glass of water.”

Primula florindae RHS AGM

Whorls of deliciously scented flowers in a range of colours from early summer until autumn, followed by very ornamental seed heads. Likes: rich, damp, fertile soil, full sun/ light shade. Height 90cm. Jimi says: “Harvest/sow fresh seed ‘in the green’ to guarantee better germination and lots of young plants.”

Persicaria polymorpha

Tall plumes of frothy white flowers from late May into autumn. Likes: Full sun to light shade, a moist soil. Height 150-200cm. Jimi says: “Looks like it could be invasive but is actually very well-behaved.”

Euphorbia ‘Goldener Turm’

Great plant to weave throughout the flower border with handsome foliage and wonderful lime-green flowers from late spring until late summer. Likes: full sun/light shade, fertile, well-drained soil. Height 100cm. Jimi says: “Propagate plants from cuttings taken in February.”

Meconopsis napaulensis

Ornamental leaf rosettes that resemble giant snowflakes are eventually followed by lofty flower stems carrying numerous blood-red flowers. Likes: full sun/light shade, a humus-rich, acid soil, shelter. Height up to 240cm. Jimi says: “This plant is monocarpic, so dies after flowering. Raise more each year from fresh seed collected and sown in late summer.”

Dahlia australis

Tall, tuberous perennial that produces large, lilac, yellow-eyed flowers from early summer until December in the gardens at Hunting Brook. Likes: Full sun, moist but well drained, humus-rich soil, lift tubers after first frost. Height 150-180cm. Jimi says: “Regularly dead head and raise new plants from seed sown under heat in spring.”

See huntingbrook.comand juneblake.ie

Jimi Blake will be running a one-year Plant Person’s course at Hunting Brook Gardens in September.

This week in your garden . . .

Clip back hedges, spray roses against blackspot, continue to feed/ water plants in the glasshouse or polytunnel, nip out side-shoots of tomato plants.

Irish horticulturists riding high Hats off to Irish garden designer Paul Martin, who won gold at the recent Singapore Garden Festival; Seamus O'Brien, whose book In the Footsteps of Augustine Henry recently won the international CBHL award; Dublin-based Tully Nurseries, whose new plant introduction, Hebe 'Rhubarb Custard' won Best in Show at the
recent HTA show in the UK