Get the ‘Chelsea look’ with iris

Siberian iris and Viburnum plicatum

It looks like we have a few pleasant days to enjoy, until mid week. A good time to plant because things will get watered in!

The RHS Chelsea Flower Show is about to fill the TV schedules this week and you may be fortunate enough to be visiting the show yourself. In either case it is pretty certain that we will be seeing lots of iris among the other early summer flowers. The trinity of the iris bloom is so familiar that it is one of the flowers that anyone can name, even if they have no interest in flowers.

I have always loved iris and even held a National Plant Collection many years ago. I still grow lots, though my current garden is not as suitable as past gardens for my favourite Tall Bearded iris. Even so, as usual, all the photos are from my own garden. Fortunately there are many different kinds and whatever your soil, site or preferences, there is an iris (or two, or dozens) perfect for you.

Tall Bearded iris prefer a well-drained soil and full sun. They also thrive in chalky and limy soil

The most familiar are the large and colourful Tall Bearded iris. These are the ones that spread by thick rhizomes over the surface of the soil. They need as much sun as you can give them and, if neglected, often grow into large, ugly clumps that flower poorly. They are often passed from garden to garden and even though the older kinds have their charm, newer, named kinds are generally superior. They are best divided and replanted in July or August, after flowering. This gives them the chance to root and get established before winter. They should then be able to support themselves when in bloom in May and June. Most will require replanting every three or four years to keep them in tip-top condition.

The bearded iris, named for the fluffy ‘beards’ on the three outer petals (called falls as opposed to the three upright petals called standards) all have creeping rhizomes and include smaller kinds. The Standard Dwarf Bearded iris (above) are great for the front of the border or rock gardens. They bloom earlier, in late April and into May, and have smaller flowers, in proportion to the size of the plants. Of course there is every possible combination of colours apart from true red.

Siberian iris are perfect for heavy soils

If your soil is rather heavy and lays wet then the bearded iris, which are bred from plants that grow naturally in sunnier climes, may not be for you. Instead you will be able to please the Siberian iris. These are not strictly Siberian but they are as tough as the name suggests. These are much less work than the bearded iris and do not need such regular division. They tend to bloom after the bearded iris and although the most common are in shades of blue and purple there are lots of other colours. The older kinds have small flowers with recurved falls but the more modern kinds have flatter and showier flowers. Yellow and complex shades are becoming more popular and these are great for clever colour combinations in borders.

‘Flying Fiddles’ is an unusual combination of colours

Siberian iris are long-lived plants but eventually they can die out in the centre of the clump, forming a ‘donut’ shape. At this stage they can be dug up, chopped into sections, in autumn or spring, and replanted.

Spuria iris are bold plants with intriguing flowers

Once the Siberian iris are fading, in July, the Spuria iris come into play. These are tall plants that create vertical accents in the border. They are tough and easy to grow in even heavy soils and although not common, are worth looking for.

A much-neglected group are the Pacific Coast Iris, so named because they are bred from the dozen or so species native to the Pacific Coastal areas of the USA. They are all compact plants, mostly with evergreen, strappy leaves, and flowers in almost every colour. They thrive in part shade or sun if the soil is not too dry and they prefer acid, humus-rich soil so if you can grow camellias and rhododendrons they will thrive in your garden.

The most spectacular flowers are produced by the Japanese water iris, sometimes called the ‘Clematis-flowered’ Iris. These are most often associated with water and, traditionally in Japan, they flood the fields of these iris at flowering time. But they dislike being in water in winter and they prosper in any soil that is not too dry in summer – they are not really pond plats. Their huge, flat flowers are truly magnificent and they grow well in any soil provided it is not dry in summer and is acid. I have been surprised at how well they grow in my rather sticky clay.

There are many more iris but these are the most common types. There will be at least one that will make itself at home in your garden to give you the Chelsea Look.

Weekly jobs

Climbers – Tie in and support the new shoots of clematis, roses and wisteria

Fill gaps – if you have gaps in borders, you can fill them with hardy annuals sown direct where they are to bloom. Nasturtiums, calendulas and sunflowers are among the easiest because the seed are large and easy to handle

Potatoes – earth-up the shoots of potatoes, pulling up the soil to cover the shoots to protect them from frost and prevent light reaching the developing tubers

Box – trim box hedges and topiary

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