Saturday 17 March 2018

Diarmuid Gavin's top 10 plants to give your garden an injection of oomph in late summer


Gardener Diarmuid Gavin. Photo: Fran Veale
Gardener Diarmuid Gavin. Photo: Fran Veale
Sollya heterophylla

Diarmuid Gavin

I create a lot of gardens and I love the process of designing them, choosing the plants and using those plants to paint colourful pictures. Usually, after they are planted, I drop in, every six months or so, to check up on the designs and how the plot is melding together.

This year I have a lovely experience of minding the Garden of Pure Imagination at the Dundrum Town Centre in Dublin. Since May, the blooms and blossoms have been non-stop - and they will continue to flower until the garden gives its final performance on September 10.

Keeping it colourful for such a long season can be tricky. The first enthusiastic flush of spring and early summer flowers have faded. So what will begin to shine in August? And which which species prolong the garden party in your plots, allowing the colour procession to continue?

Listed below are the flowers I hope will see this particular joyous plot continue its performance right through to September. They're my top 10 late-summer colour - and any one of them might be perfect to keep summer going in your plot.

1 Hydrangea aborescens 'Annabelle'


A 'posh' plant much in vogue at the moment. It has beautiful white globes of flowers in July, which will gently fade to green in early autumn. Like other hydrangeas, it doesn't like to dry out. No need to cut back hard in spring - a light prune will do.

2 Sollya heterophylla

Sollya heterophylla

Also known as bluebell creeper, Sollya is a pretty evergreen twining climber, covered in delightful blue bell-shaped flowers in July. It's somewhat frosttender, so only suitable outdoors in coastal or milder areas, but can make a wonderful summer conservatory plant as well.

3 Verbena 'Hurricane Pink'


Tender bedding plants are great fillers at this time of year, brightening up gaps in the borders or rejuvenating tired pots and containers. This compact little verbena is full of frilly pink and white fun, and will keep going for the rest of the summer as long as you keep deadheading.

4 Osteospermum 'Voltage Yellow'


African daisies are long-flowering, so this blast of yellow will keep going until autumn. And it's not only the orange variety - they can be sourced in a wide colour range.

5 Eryngium

Also known as sea holly, these come in wonderful shades of blues and intense violets. It's an easy-care perennial that enjoys full sunshine and well-drained soil. It's a strong, shaped plant for your border and its flowers, which can also be dried very well, are long lasting. Very popular with butterflies and bees as well.

6 Veronicastrum virginicum 'Fascination'


An elegant upright perennial with dense, slender, branched spikes of small, light, violet-blue flowers - like delicate, mauve wands - which flower in summer through to early autumn. Plant in sun or partial shade in moist but well-drained soil.

7 Achillea millefolium 'Red Velvet'


There's a great diversity in colours with Achillea, commonly known as yarrow. Although the best-known probably is 'Moonshine', for its sulphur-yellow flat heads, there are more subtle pastel tones in cultivars such as 'Lilac Beauty'. Right now I'm loving the deep burgundy tones of 'Red Velvet'. Loves full sunshine, and looks striking dotted through a border.

8 Lythrum virgatum 'Dropmore Purple'

This is a cultivar of our native Purple loosestrife, which flowers from summer to autumn. If you're out walking you may notice it in damp areas such as boggy meadows or beside streams. Tall spikes of pinkish purple flowers are nectar-rich and attract bees and butterflies. Although it prefers dampness in the wild, it will do fine in your garden so long as the soil doesn't completely dry out.

9 Agapanthus

If you like having globes of alliums dotted around in early summer, consider African lilies for midsummer. 'White Heaven' is bursting into flower right now - huge white globes on very sturdy stems. They also come in deliciously vivid blues and are suitable for pots as they love having their roots tightly squished together. Full sun is ideal and this will flower from now through to September. In our Dundrum garden we've used little signs proclaiming 'Beware of the agapanthus!' that have intrigued children (of all ages). It was my way of keeping small people to the paths but it's time to come clean: agapanthus will only provide beauty, they don't cause any harm!

10 Helenium 'Short 'n' Sassy'

My last choice is this cheerful daisy, which has bright orange and gold petals surrounding a chocolate-brown cone. It's ideal for smaller gardens due to its compact shape and is a plant with straightforward requirements - it likes to be in a bright and sunny position in good, well-enriched soil that doesn't dry out. Divide in spring to increase.

For flowering perennials and many summer bulbs, an open, sunny aspect with a free-draining soil is best, but add plenty of humus material to help retain water and nutrients around the roots.


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