An eye for iris
For winter scent you can’t beat the robust Algerian types
How accommodating of Iris unguicularis (the Algerian iris) to offer us summer flowers and scent in the coldest months of the year. This rhizomatous perennial that you may know by its old name Iris stylosa, is a native of Greece and Turkey. It always catches me out as I stroll the garden in winter as it has such a long period in which it can flower that you’re never quite sure when that might be. If the summer before has been long and hot the winter flowers tend to be more plentiful.
At Stockton Bury Gardens in Herefordshire we have a couple of mature clumps thriving at the foot of a south-facing wall in the kitchen garden.
I’m estimating that these clumps, reaching about 30cm (1ft) in height, have been in the garden for at least 10 years, and in that time they’ve never been touched. Not one minute of maintenance has been bestowed on these plants so I’m confident in describing them as no maintenance! But, it takes a while to settle in and flower. Plant this year and you might not see a flower for a couple of years. It’s for this reason that you often find the best clumps in very old gardens where the plants have been left untouched for years. Although it’s well documented in gardening books that you can divide these plants in autumn, I wouldn’t. My advice would be to leave them well alone. If you can’t avoid the temptation to divide, then expect each plant to take time to settle and flower again.
The perfect planting position is at the foot of a south-facing wall. The soil must be well-drained and with a pH that’s neutral to alkaline. Sand, loam, clay or chalk are all acceptable and a soil that’s on the poor side is often preferred. Although it requires a hot spot, the Algerian iris is hardy. It will thrive in all parts of the UK and copes with temperatures as low as -15C (5F).
Flower power
The flowers appear anytime from January until March. Although the plant is hardy, the flowers will be damaged by the frost. For this reason,
I pick the fully open flowers if a frost is forecast. These flowers are the perfect fit for an egg cup, and I guarantee that anyone who visits your home won’t leave without passing comment on the summery blooms. Although small, the scent is big!
It’s fair to say that this low-growing iris offers nothing to the garden until it flowers. The grassy, evergreen foliage can only be described as a mess. Tempting as it is to plant this sun lover surrounded by other taller plants to hide its foliage, don’t. Casting shade over the plant will lead to a lack of flowers. I prefer to plant them in a space of their own. Either side of the clumps in the garden here I have some nerines, as these enjoy the same conditions and don’t cast too much in the way of shade. The straight species of Iris unguicularis offers pale blue flowers with yellow and white markings. Each flower is about 6cm (2¼in) across and held no more than 25cm (10in) from the ground.
If you’re looking for an Iris unguicularis with a twist, then ‘Mary Barnard’ will tempt you. She has all the robust charm of Iris unguicularis but her flowers are a stronger violet-blue. For darker purple flowers grow ‘Abington Purple’ or ‘Walter Butt’ if you prefer a pale lavender-blue flower.