It took me a while to warm to Dietes grandiflora but now I love the pretty butterfly-like blooms that we get all summer. We have a large patch of it but as overhead shade grew, the incidence of flowers decreased year by year. It wasn’t until a big chunk of it was moved to a sunny spot – left to sit upon the ground, in fact, and never even planted – that I realised its flowering potential was much greater than we had been seeing in recent times.
Last summer, I looked at the somewhat neglected and misdirected state of the gardens around our swimming pool. Unlike most pool owners that I see, we did not locate ours in a prime garden position and turn it into a landscape feature. We knew from past experience that we would never maintain a pristine pool twelve months of the year and we did not want it in full view. Instead we found a side-line position which was still convenient and sunny but largely out of sight. In these circumstances, there is not much point in planting for year round appeal. We only want it looking good over summer. I removed all the bulbs and spring flowering material and opted for a combination of a dark-leafed ornamental taro (black colocasia) in combination with Dietes grandiflora. As I write this, it is too early to claim huge success but it is looking promising and will be easy to maintain. ***
There is nothing quite like becoming a staple of amenity landscapers to remove the mystique of a plant. And indeed I photographed the pale yellow Dietes bicolor in a shopping centre carpark where it grows in the harshest of conditions – windswept, foot trampled, bashed by cars, hot, dry and left to its own devices. And still it flowers for many months on end. We don’t have it in our garden, but I wouldn’t turn it away. Grown in slightly kinder conditions, I am guessing it may flower more prolifically and an annual groom of spent foliage would keep it looking tidier. It may be that D. bicolor is favoured in such plantings over its prettier relative, D. grandiflora, because it is more compact at about two thirds the height.
Mark was sure the showy, tall iris that we have also planted by our swimming pool was a dietes. But no. When I went to look it up, I found there are only six different dietes. Five are from southern and eastern Africa and, oddly enough, one from Lord Howe Island. The pool iris is very tall – stems maybe two metres high at times and generally capable of holding themselves up. I spend a bit of time on hot summer days floating around the pool on a lilo and those pretty flowers waving above me are a delight. Some detective work initially had me thinking it was a Cypella coelestris which comes from Brazil, Uruguay and Argentina. But it appears I was wrong, too, and it is in fact a Neomarica caerulea – the walking iris – from Central and South America. It is pretty international, the iris family. After spending some time analysing photographs on line and looking at descriptions, it was a reader who gave me the simplest way to tell them apart. The cypella grows from a bulb and the neomarica from a rhizome. I rushed straight out to look and, sure enough, rhizomes. In my defence, they are closely related, along with the trimezia.
Each flower on the neomarica only lasts a day, but it continues to flower down the stem, a trait that can be seen in other irises and iris relatives. In our conditions, the neomarica is not fully deciduous, though it dies back to a neat clump of foliage through winter.
A net search tells me that a number of American sites describe the cypella as being like a blue tigridia. We grow a fair number of Tigridia pavonia and all I can say is ‘oh really?’ To me, it is indubitably iris with its three upright blade petals and its fall of three sepals. While the tigridias are also members of the iris family, they are not as obviously iris-like. Maybe renaming them is just somebody’s idea of a marketing ploy to sell a plant which is not so well known.
Tigridias, however, share similar characteristics to both dietes and neomarica in that they are summer flowering, each bloom only lasting a day but continuing to open fresh flowers from the same stem, so easy to grow that they might be deemed to have weed potential and somewhat loose in form. Tidy gardeners may describe them as scruffy and they don’t fit so comfortably into a tightly maintained small space. But for those who like a certain summer abandon with lots of flowers, these are delightfully casual options for the summer garden.
Current update on the colocasia and dietes planting is that the former is doing brilliantly and out-competing the latter entirely on height. It may take another season to see if the dietes is able to rise to the required height to get enough sun to bloom.
First published in the January issue of New Zealand Gardener and reprinted here with their permission.