I’ve always been astonished at how easy and tough Iris are – I remember proudly showing off a clump in our front garden when I was about ten years old. In fact, that same clump moved to my mother’s new garden and is still there today. Their hardiness somehow seems too good to be true, but (luckily for us gardeners!) it is.
What’s wonderful about this plant is that there’s a variety of iris that’ll be in flower through every part of the year, which is due to the many different types that are available. Very few genera of plants can boast this quality and makes them something quite special.
Many Iris come from the Mediterranean and other dry climates, and although some can do very well in south facing sites in Wales, it’s the wet-loving varieties that do the best. Even if sticking to types that prefer wetter conditions, there’s still a huge choice available to you. Since the 1960s new varieties have arrived through a tremendous amount of breeding and from importation from Japan. We’ve even seen new species arrive that were not previously in cultivation.
Iris are broken down into sections to make it easier to choose from the plethora of different types available. Ones that prefer wetland conditions are known as beardless iris (named for their smooth lower petal) making it easier to identify when shopping and browsing.
Siberian Iris have very delicate slender flowers, are happy in normal to very wet conditions, and produce many flowers in late May. There’s hundreds to choose from, but two of my favourites are Iris ‘Butter and Sugar’ and Iris ‘Flight of Butterflies’ – for best flowering, I advise planting them in open conditions. This particular group also contains Iris chrysographes ‘Black Night’ which has flowers that are such a deep violet colour they look black at first glance.
The water Iris, or Laevigatae Iris, is the group which contains our native flag Iris which are happy in very wet and marginal conditions. Again, there are hundreds of types, especially cultivars bred from the Japanese Iris known as ensata or kaempferi. These have gloriously showy flowers which come in doubles or singles and in many different colours. Iris ‘Caprican Butterfly’ is a particularly striking member of the ensata type, and Iris ‘Holden Clough’ and ‘Gerald Darby’ are excellent laevigata types.
Another iris that thrives in damp conditions is the less common Louisiana type. They have very interesting zigzagged stems and come in a very wide colour range: for example Iris fulva has orange flowers and Iris x fulvala has beautiful, striking purple-red flowers. They come in a variety of heights ranging between 40 and 120cm and are very hardy, although if you’d like to see them at their best then this tends to happen with a hot summer.
The Spuria group are some of the tallest types of Iris and are also very happy in wet conditions. Iris ‘Shelford Giant’ can grow up to two metres with very attractive yellow and white flowers that provide a lot of impact. Another example is Iris ‘Adobe Sunset’ which have wonderful orange-yellow flowers.
A less common type is the pacific coast Iris. They usually have evergreen leaves and their flowers come in many colours and have beautiful veining on their petals. Iris ‘Banbury Beauty’ has very subtle but stunning lavender flowers – it’s a shorter variety and takes well to shaded areas. Iris douglasiana is one of the most vigorous and produces variable flower colours. There’s also many more hybrids of this variety that are becoming available.
All the iris I’ve mentioned above are happy in wet conditions and will take a degree of shade – quite the necessity for most British gardens! Unlike many types of Iris, these all produce multiple flowers on each stem. They’re fully hardy to -150C and grow into large clumps that are easily divided. Other than cutting back in autumn and dead heading, they require very little care and are pest and disease free. One of the few criticisms people have with these plants is that the flowers don’t last particularly long. RHS trialled plants that have been awarded a garden merit are ones that seem to flower a little longer and are in general better plants. I find established clumps of Iris at Aberglasney give a good display for just over a month and are a real hit with our visitors!