Tag Archives: Dietes grandiflora

Summer iris

Dietes grandiflora

Dietes grandiflora

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.

Dark colocasia with dietes

Dark colocasia with dietes

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. ***

Dietes bicolor

Dietes bicolor

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.

Cypella coelestris

Neomarica caerulea

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.

Tigridia pavona

Tigridia pavonia

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.


*** Postscript

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. 

‘Editing’ the plants for a lower maintenance garden

A few years ago. It is amazing how much the skyline of trees has changed since. My feet.

A few years ago. It is amazing how much the skyline of trees has changed since. My feet.

Editing, dear New Zealand readers. Cleaning up the borders and beds is often about editing the plantings.  I know this because I read a certain amount of British garden media.

I have certainly been editing the plantings in the gardens around our swimming pool. It seemed a good summer occupation and on a few hot days this week, the flow between gardening and cooling off in the pool has been excellent.

The gardens were put in when we built the pool in the late 1990s and, in that clichéd way, we naturally opted for a sort of tropical feel. It was never thought out very well at the time. In the years since, I recall doing one relatively major rejig of the gardens but beyond that, they have only had the most perfunctory of care and minimal maintenance. This often included plugging gaps with whatever I had to hand.  And it was showing that lack of attention.

I am a more thoughtful gardener than I used to be. I think that comes with experience. Knowing that we were unlikely maintain a pristine swimming pool, we had chosen from the start not to make it a key landscape feature but rather to site it discreetly where it is largely out of view. I am not keen on garish blue pools taking centre stage so ours is also a modest dark grey and we went with a black pool cover.

Curculigo, euphorbia and Ligularia reniformis, lush enough to pretend to be tropical and low maintenance

Curculigo, euphorbia and Ligularia reniformis, lush enough to pretend to be tropical and low maintenance

The upshot of this is that I figured we want a really low maintenance approach to the gardens around the pool and that it should be specifically targeted to the swimming season – which for us is mid to late December through to mid February. There is no point in putting in plants that flower outside that time because we won’t see them. Extreme editing was called for to eliminate my previous efforts to plug gaps and add seasonal interest with assorted perennials and bulbs.

I am quite happy with the earlier effort blocking up the Ligularia reniformis with Curculigo recurvata (nice foliage contrast and happily co-existing). We removed all but one of the damn dangerous euphorbia (E. mellifera, I think) which seeds far too freely and has disappointingly insignificant flowers but compensates with good form and foliage. Ligularia reniformis is getting to be a cliché in New Zealand gardens and I will restrict how widely we use it elsewhere in the garden, but it is very handsome and lush here, reaching well over a metre in height. However, the compact red dahlia hybrid will have to go. Not our style. Too suburban in our context.

Pachystegia insignis in the foreground, Xeronema callistemon behind and overhead a large Aloe bainseii

Pachystegia insignis in the foreground, Xeronema callistemon behind and overhead a large Aloe bainseii

The Pachystegia insignis (Marlborough rock daisy)  and Xeronema callistemon (Poor Knights lily)  flower outside the summer season entirely but these native plants are not the easiest to grow in our environment and the plants are handsome and well established with good foliage contrast. Besides, it is not in our nature to edit our plantings down to a simplistic mass.

IMG_6956It is the next ten square metres or so where I have gone for a block planting. It was a mish-mash. No longer. I chose to use two common plants – the pretty but tough Dietes grandiflora and black taro. At least we know it as black taro but I am not sure if it is a colocasia (in which case it may be ‘Black Magic’) or an alocasia.  It looks very new and raw at this stage, but I expect it to be a pleasing combination with plenty of pretty flowers next summer and good foliage interest. And low maintenance, without looking like a supermarket carpark.

Patience is a virtue. The freshly planted dietes and black taro.

Patience is a virtue. The freshly planted dietes and black taro.

I see some debate in garden media about whether digging and dividing perennials is necessary. Many folk seem to dread and shun digging – hence the no-dig craze for vegetable gardens. All I can say is that since I started doing a lot more digging and dividing, the garden looks hugely better for these efforts and the perennial plants thrive in more friable conditions with less soil compaction. It is also a learning experience as I experiment with plant combinations and think through the seasonal effects. It is a whole lot more interesting than mere garden maintenance and gives an opportunity to review and edit the plant selections. And it doesn’t even cost any money because I am working with plants already in the garden. There is nothing to fear from increasing the dig and divide regime.

IMG_6892And for those of you who don’t follow the garden Facebook page, I offer you my little study in dietes blooms. It makes no logical sense to float them in water, because they are not damp-loving plants at all. I just thought they would look charming, and they did – first in the swimming pool and then I gathered them all (slightly battered) to float them in the stream. Because I could.



Plant Collector: Dietes grandiflora

062There is nothing unusual about the dietes flowering at the moment, but don’t let the fact that it is much favoured by amenity landscapers put you off. The reason it is seen so often in shopping centre garden plots is because it is tough and easy care.

It is a South African wild iris. Originally it was thought to be a moraea – commonly known as peacock irises – but that family grows from corms whereas the dietes forms rhizomes. Its flowers link it to moraeas, its rooting structure to the iris. Apparently the word dietes means ‘having two relatives’. ‘Grandiflora’ just means large flower.

The foliage is narrow, upright and pointed and it is evergreen. For most of the year, it just looks anonymous and not very exciting but it has such pretty flowers at this time. These are short lived but, as with many other irises, there is a succession opening down the stem. If the blooms remind you of an exotic butterfly, you may be pleased to hear that it is sometimes referred to as a butterfly iris. It flowers best with sun. While the plant will grow in relatively shady positions, you won’t get anywhere near as many blooms so try for full sun or somewhat dappled light.

As a garden plant, unless you want your place to look like a supermarket carpark, veer away from mass planting in favour of interesting combinations. I think it looks wonderfully effective planted with the tractor seat ligularia (Ligularia reniformis) but any contrasting big, luscious foliage is going to work.
017 - Copy
First published in the Waikato Times and reprinted here with their permission.