Diarmuid Gavin’s guide to creating a rainbow with colourful irises

With its beautiful flowers and sweet fragrance, this plant blends seamlessly into any garden style

Forsythia is suitable from growing from cuttings

Bearded ris

Forsythia

Time to plant up your hanging baskets

Forsythia is suitable from growing from cuttings

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Bearded ris

Diarmuid Gavin

May 14 2022 07:30 AM

A combination of rain and sunshine has accelerated plant growth this month and spring gardens are in full bloom. My front garden is a haze of blue flowers as the anemones, bluebells, brunnera and omphalodes are all in blossom.

The tall echiums are also starting to flower and soon will be buzzing with bees. Foamy white flowers of Anthriscus dance in the breeze. The picture will be complete when the tightly folded buds of the bearded iris give way to their opulent violet petals.

Named after the Greek goddess of rainbows and messenger of the Olympian gods, this is a spectacular plant which combines beautiful flowers, architectural foliage and a sweet fragrance.

There are hundreds of different cultivars with colours ranging through the rainbow and beyond to include bronze, brown, black and the purest of whites. Some are bicoloured. For example, ‘Supreme Sultan’ has wonderfully contrasting yellow standards (the upright petals) and deep burgundy falls. Others have richly contrasting beards — the furry little line of hairs on the falling petal which act as a landing strip for bees to guide them into the centre of the flower.

Recently, I saw a small front garden in the beautiful French town of Villefranche-sur-Mer entirely planted with this species. It’s a plant I associate with France probably because of visits to Claude Monet’s garden in Giverny, where great blocks of iridescent blue irises shimmer in the golden sunlight.

They are thought to originate in the Mediterranean, and this gives us the key to understanding what conditions they like. While some other types of iris, for example the yellow flag iris, enjoy moist, boggy conditions, the bearded iris likes it hot, dry and sunny, preferring an open position where the rhizomes can bake all summer long.

The rhizomes should be purchased and planted in late summer and autumn — they don’t like any disturbance at all in spring. Plant shallowly in well-drained soil with the tops of the rhizomes exposed. If you plant too deep, they won’t flower, and the rhizomes may rot. Congested plants can be lifted in late summer. Remove older plants of the rhizome and replant newer growth. Other than this, they are low maintenance and robust plants. The taller varieties sometimes require staking when they become top heavy with flowers.

They look great planted en masse and when mixed with other plants, but make sure their neighbours don’t shade or crowd them out. The strong, sword-like foliage and lush, extravagant flowers allow them to blend seamlessly into a romantic cottage garden scheme, a formal elegant design, or a bold, contemporary look.

Cut the flower stems down after they have finished flowering so they can divert their energy to increasing rhizomes. By winter, all the foliage will die down until the spring. Some varieties are re-bloomers, which means a second flowering in autumn, a poignant reminder of what has been. Examples include the rich, violet-hued ‘Cantina’, the lovely lemony ‘Buckwheat’, the soft blue of ‘Victoria Falls’ and the gorgeous white ‘Immortality’.

Plant of the week

Time to plant up your hanging baskets

Nemesia
It’s time to plant up your summer containers and hanging baskets, and if you want to have clouds of flowers and colour throughout the summer, consider including nemesia in your selection. The small snapdragon-like flowers are bred in lots of colours and are usually fragrant. Native to Africa, they will flourish in a sunny position, but don’t let them dry out. Deadhead flowers to encourage repeat blooming, and you can also cut them back to encourage new growth. In Wicklow, they bloom sporadically through winter as well.

Reader Q&A

Can I grow forsythia from cuttings?
Alan

Forsythia is suitable from growing from cuttings

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Forsythia is suitable from growing from cuttings

Yes, forsythia is suitable to propagate from cuttings. The best way is to use semi-ripe cuttings — these you get in late summer to mid-autumn. This is fresh growth from this season, but the stem has become thicker and harder and so is more likely to survive than a softwood cutting that you would get from the plant right now. Take a cutting of about four-to-six inches, just below a leaf, and once you have prepared it by removing the lower leaves and dipped it in hormone rooting solution or powder, plant in a pot. It should be rooted and ready to transplant in autumn of next year.

Submit your gardening questions to Diarmuid via his Instagram
@diarmuidgavin using the hashtag #weekendgarden

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