I have been married to the same man for over 35 years now and he has spent much of that time curbing my tendency to hyperbole but I am about to open with a sweeping statement this week.

The single biggest issue that is dominating garden writing and garden theory at this time is that of sustainability. Through all the media, garden presenters, writers, planners, Uncle Tom Cobley and all are talking sustainability. Sometimes it comes in the guise of organics, but it is about a great deal more than just organics. And it has only come to the fore in the last few years but I believe that we are in a time of extremely rapid change again and the somewhat alien concept of sustainability in gardening will be accepted as the norm in a very short space of time.

Ornamental gardening doesn’t have a great history of being sustainable. Agriculture and food production is different. It is integral to human survival and even back in the days of subsistence living, it had to be able to be continued. The current strong lobby for organics in food production is really a turn of the wheel back to how things used to be done. It is only in recent history that we embraced the chemicals, pharmaceuticals, manufactured fertilisers and all the rest in a drive to lift production and to increase profits.

But ornamental gardening is rather different. Historically it was the domain of the rich and the powerful minority. You want a sweeping, gently rolling countryside view from your terrace? Get Capability Brown in and move a few untidy villages out of the way. You fancy a pleasant and cooling water garden in the middle of a dry and arid area? All such problems can be solved if you have the money and the power. Even the ancient Hanging Gardens of Babylon were testimony to man’s control over inhospitable nature (apparently in the quest to please a foreign born wife). Versailles was famous for the ability of the gardening minions to totally change the colour scheme of the bedding plants overnight so that when the French king and queen looked out of their window in the morning, instead of pink petunias and purple cineraria, they were looking instead at yellow pansies and blue forget me nots. I once used to know how many thousands of plants it took to achieve this overnight transformation.

In recent times we have become a great deal more democratic and ornamental gardens are no longer limited to those with power and deep purses. But we have tended to take on the trappings, albeit in a miniature form. A water feature is almost mandatory, even if you have to install a pump to get the water to the right place. Statues, urns, sculptures – all hark back to the rather grander gardens of yore. So too the sweeps of lawn, vistas (though many of us have to borrow them) and most of the trappings of ornamental gardening.

It is all about controlling our environment. About creating something we find pleasing and holding the unpleasant aspects of the world beyond at bay so we can have our own tranquil haven where we are in control. At its best, gardening is about working with nature. Alas, more often it is about controlling nature and bending it to our will. And that is the bit that is not sustainable.

Gardening is about loving beauty as we see it individually. Save us from the utilitarian approach whereby planting ornamental trees is replaced solely by food bearing specimens. Yes, I enjoy the apples off our apple trees and the plants themselves are attractive enough, but they don’t make my heart sing like the sight of Magnolia Iolanthe in full bloom this week. I will happily harvest fresh vegetables, but I don’t want to wander around admiring them as I do the flowering cyclamen and daffodils. Growing fruit and vegetables is not a replacement for growing ornamental plants and creating a garden which feeds the soul.

But much of our talk here is focussed on how we can make our gardening practices more environmentally sound and what compromises we are willing to make in order to reduce our footprint on this planet. Truth be told, Mark is more prosaic in his interpretation of sustainable gardening. He sees it at a far more personal level of ensuring that the garden we continue to develop and extend remains manageable and able to be maintained to the standard we want in the long term. Part of that is shunning at least some of the questionable gardening practices, particularly the routine application of sprays.

I guess that adapting our gardening practices to be more sustainable and more environmentally friendly is all about individuals taking small steps rather than dramatic turnarounds. The domestic lawn is probably the worst crime. We are not willing to cast out the lawnmower (and we console ourselves that at least we don’t drive to work) but we do use a mulcher mower so the clippings are not removed. You can not keep stripping off the grass and expect the lawn to remain healthy so you either catch the clippings and feed the lawn or you mulch the clippings back in as part of the mowing process. Mark has a dislike of hormone sprays in the garden, so he has generally stopped spraying the lawn. We will take out the flat weeds by hand and have learned to live with some of the others.

Gardeners should be seriously questioning the use of plants which require routine spraying to keep them healthy. Strong, healthy plants will often withstand diseases and pests. If they won’t, maybe it is time to replace them different selections that will.

Mulching garden beds not only feeds the soil (reducing the need to fertilise), it also suppresses weeds. Being maniacal mulchers, we are now of the view that bare soil anywhere but in the vegetable garden is a black mark. Mulches also reduce or remove the need to water. Yes it rains a lot in Taranaki and water is rarely a problem in the north, but it is still hard to justify the regular use of water in an ornamental garden when it can be managed without. Delivering water to your garden tap still comes at an environmental and financial cost.

Learning how to make compost saves taking green waste to the rubbish transfer station (and buying in compost and mulch in return).

Small steps in gardening will not change our planet but it may just help to make us a little cleaner and greener. It is a myth that gardeners are environmentalists but it would be nice if we could be.

We have been watching Around the World in Eighty Gardens on the Living Channel. Sadly we wised up too late to the fact it was screening to catch the New Plymouth garden, Te Kainga Marire, which was featured in one of the early episodes but we have seen Monty Don (the host with an unlikely name) gallivanting around South America, the United Kingdom and Europe visiting gardens of his choice across the whole spectrum from very grand to very modest.

There is a bit of an open verdict here about our Monty as a garden host, though it did strike us in the last episode that he does not show much interest in plants. He is presenting gardens as form and vision through history across the globe and certainly has a fine grasp of the big picture and an avid interest in the social milieu which prompts the establishment of different types of garden. Big picture gardening makes good television and is undeniably impressive but can also be quite impersonal. To be fair, Monty does intersperse with some little gardens but he does not focus on the plants. Maybe our ambivalence is because we like to see the little pictures within the big frame and gardening to us is all about a passion for individual and interesting plants as much as good form and design.

We caught another programme which showed a London garden which was all green with not a flower in sight. They claimed no flowers at all but I am sure I saw a rhododendron so either the owner disbuds it or there was a slight exaggeration. It was a garden which was all about form and nothing at all to do with colour or seasonal change. Certainly it had a restful quality but it could perhaps be a little gloomy at times.

Would I ever want to garden without flowers and seasonal change? Never. If we didn’t have the flowers, we wouldn’t have the tuis. At the moment the campanulata cherries are in full bloom. The tuis don’t sit still long enough for us to take a census but there must be over a hundred of them bickering and squabbling over the bounty. Photographer friend, Fiona Clark, has been videoing our tuis for the last two seasons and I will advise the website address when the sequence goes on-line but she became a little frustrated last week when one large and aggressive tui decided an entire tree she was filming at the time was to be his and his alone, fighting off all pretenders. Tuis are territorial birds not given to living in happy harmony, but it is a delight to see trees which are alive with swarming birds and to see entire flocks flying in to the most desirable trees in the morning.

Campanulatas are the Taiwanese cherries (as opposed to the later flowering, more delicately coloured and often fluffy Japanese cherries). They can set seed a little too freely and indeed have been declared a noxious weed in Northland so if you are planting them, look for ones advertised as sterile, or that set minimal seed. While they can provide splendid food for tuis, we don’t need a jungle of wildlings in our native bush. If you already have one that seeds, stay on top of the seedlings because they are deep rooted and not that easy to eradicate if you let them get away on you. Our resident pigeons have reduced our crop of wildlings in recent years.

If we gardened without flowers, we would not have had the ephemeral delight of the English snowdrops (galanthus) or this week’s dwarf daffodils which are in full flight. Similarly, if we gardened with only the big picture in mind, we wouldn’t be enjoying these tiny treasures either.

Magnolia Burgundy Star in full glory

Burgundy Star is just opening her flowers. Photo Abbie Jury

The flower-free zone would also mean missing out on the magnolias which are opening now. I had a very pleasant interlude at the weekend with a visit from an Auckland architect who was seeking magnolias for her new garden. Not for her the uniformity of evergreen magnolias or restricting her range to one variety only. No, she was after big, blowsy, spectacular and seasonal. I warmed to her instantly, recognising a fellow traveller. She knew and I knew that she was overplanting her small section, but she wanted to fit in as many OTT trees to cover as long a flowering season as possible. That exuberance is refreshing in an era when good taste in gardening and design is often equated to restraint bordering on the anally retentive. And it is unusual in somebody who works professionally in the design sector without a great background in plants.

A flower free, or all green, or totally evergreen garden is usually designed to be as static as possible. Ditto the low maintenance garden. The creative process happens once at the very beginning. From then on it is straight maintenance, outdoors housework. There may be a bit of a makeover or renovation every five years or so but basically it is repetitive work to maintain the status quo. As one who finds housework a dull but necessary chore, the prospect of reducing gardening to the same level of repetitive activity does not appeal at all.

What I like about gardening is the constant creative thinking and action. To achieve that, you need to be willing to change the scene by altering planting combinations, adding extra bits of interest, replacing underperforming plants, getting excited about discovering a plant you didn’t know about before, coming upon something new in flower or growth each week and responding to the changing environment. Those are the interesting parts, not doing edges and clipping and weeding.

It is the vibrancy of plants and seasonal change that give life to a garden and for us that includes flowers and vast range of different plants all of which have their time to shine. Good design gives a framework to hold it all together visually just as good architectural design can create a splendid house but does not make it a home. Good maintenance presents it well. But it is the plant selection that makes it come alive. We will stay with the flowers and the birds here and watch the tuis while rejoicing in the OTT display of tree magnolias in full flower over the next month or two.

A friend with a garden maintenance business rang recently to discuss buxus blight. This is a fungal ailment which attacks box plants. It was first found in New Zealand in 1998 and has been a problem in Auckland for some time. Buxus being an infinitely useful but deathly dull plant, we made contingency plans early, in case the fungus ever struck our modest metreage.

I have just paced out our box hedging and we only have around 25 metres of it plus one established topiary, so it does not exactly feature large in our garden. From the start, we figured that buxus did not warrant spraying to keep it healthy so we have always been ready to rip the plants out and burn them if necessary. We have alternatives out the back, so to speak, so taking out the buxus hedges was only ever going to be a minor inconvenience.

But Garden Maintenance Friend was horrified when I suggested he advise his clients to rip out their box hedging and replace it with something which does not get blight. Most of them have a great deal more than 25 metres and do not have the advantage of alternative plants for instant replacement. He suggested he would far rather I write a column on the topic and that his clients may take the advice better from the newspaper than from him.

The bottom line is that if you have buxus blight (or fungus cylindrocladium) in your garden, you have a problem and if you don’t do something about it, it will spread rapidly. Doing something about it is easier said than done in this day and age when a severely restricted range of chemicals is available to the home gardener. There are no heavy duty fungicides that can be bought over the counter unless you have a spray certificate. Which means that if you want to go the spraying way, you will have to employ a certificated operator. But we are also strongly of the view that gardeners should take more responsibility for their actions and that spraying a utility plant like buxus is simply unjustifiable. It is time we asked many more questions about the spraying practices which have become the norm in this country over the last four decades.

There appear to be three main ailments that hit buxus and if you have plants which are looking poorly, it may not be the dreaded blight. A dead patch in one area just above the ground is most likely to be animal urine – territory marking by dogs or a tom cat. I am not at all sure how you stop the offending animals, but it is no reason to rip out your plant.

Zephyr the dog treats the buxus hedge with some contempt. (Photograph: Abbie Jury)

There is a pinky mildew (called volutella buxi) which has been around a long time. It disfigures the plant but is not usually fatal. It takes hold in wounds so if you clip your hedge hard, it is likely to be more apparent soon after. Healthy plants can outgrow volutella so a bit of effort may retain your hedges.

The dreaded buxus blight has cut a swathe through the United Kingdom’s millions of box plants since the mid nineties, through Auckland’s since the late nineties and is likely to be the cause of dying buxus reported in Taranaki. It is the problematic one. It starts as dirty dark spots on the leaves and black streaks on the stems and spreads rapidly, causing the plant to lose all its leaves and usually die. It often shows up initially as dead patches along the top whereas the sides will appear to be fine. Research has shown it takes only five hours to start multiplying so if you ignore it, it may well surprise you by how fast it takes hold. It is impervious to cold (most fungi prefer warm, moist conditions) which is why it has taken hold in the UK. This means it does not slow down in winter. It is only very dry conditions which it dislikes and as most of Taranaki is humid most of the year, we have splendid conditions for it. Being a fungus, it increases from spores so it can be airborne which means that if you live in town and your neighbours have it, sure as eggs you will get it too. And as the spores survive in decomposing leaves for a year, it is nigh on impossible to eradicate. You may burn the offending plant (avoid the compost heap for this one) but you are not going to be able to pick up every dead leaf. You also need to disinfect all tools which have been in contact with it – household bleach apparently works.

Prevention is better than a cure. There is a tendency for owners of buxus hedges to cut them hard twice a year and, ever obliging as they are, they sprout afresh. But over a period of years, the hedges get increasingly dense as well as being filled with dead leaves which sit in the middle. I was a bit surprised when I overheard a buxus expert holding forth recently on the need to thin out buxus hedging and topiary shapes and to vacuum out the accumulation of dead leaves. Really, I thought. But she is right. And if you want to reduce the chances of getting a terminal case of buxus blight, you may like to head out now with the nippers, the clippers, the secateurs and the blower vac. Some good hygiene, housekeeping and air movement will reduce the chance of blight getting hold. But it is not a cure and personally I am not so enamoured of buxus that I think it justifies that sort of effort.

I am told that two sprays of copper a week apart with a wetting agent added can help, even cure it, so if you have affected plants you may like to try this approach. Mark is surprised that copper, which is anti bacterial and not a fungicide, could be so effective. And the information from the UK where buxus blight has been extensively researched, certainly does not bear out the copper theory. If copper is working here, it is unlikely that we have found a wonderfully simple solution and are therefore cleverer than our overseas colleagues. It is far more likely that the cause is not in fact fungus cylindrocladium. That said, it is worth a try if the alternative is the drastic step of total replacement.

If you have to rip out your buxus, burn it all. And don’t replace with more buxus. You will need to be looking to some of the alternatives that clip – coprosma, camellia, teucrium, corokia or the like. There are no species of buxus that are resistant to cylindrocladium. The fungus does not reside in the soil so treating the soil or replacing it is a waste of effort. It is the plants that are the host.

Sadly, for owners of buxus hedging, there does not appear to be any good news as far as fungus cylindrocladium goes. The only good news overall is that it may curtail the slavish use of buxus as hedging and edging in every second garden.

I recall some years ago having two conversations in a short space of time where people regaled me with tales of coming to buy plants from Mark in the early days of our nursery. Both shared a similar experience. “It was at least 20 minutes,” said one, “before I was confident that I was going to be allowed to buy a plant.” Readers who know and like my Mark will be smiling at this point, recognising the likely truth in these accounts. He, himself, sees humour in the retelling but retorts slightly defensively that of course he was right. There is no point in selling elite and difficult plants to people who will fail with them. It will only backfire all around. It is a philosophy of retailing to which I am forward to returning.

I have one plant here which I insist on an interview before allowing anybody to buy it. It is very slow to grow, scarce as hens’ teeth and likely not available anywhere else, expensive and I don’t want to waste precious plants on unsuitable people. It is a tiny vireya species, saxafragoides. After about five years, you get a little bun of a plant measuring around 7cm across. It is reported to be the most cold hardy of the vireyas (it is in fact the mother of hybrids Jiminy Cricket, Saxon Glow and Saxon Blush) and also the most tolerant of damp conditions. But not only is it very slow to grow, I have also not had great success with it in the garden, despite, I thought, giving it optimum conditions.

A decade or more ago, vireya rhododendrons were all the rage. A fashion plant of the day, it was predicted by some that these sub tropical rhododendrons would supplant the hardier, traditional rhododendrons in areas where they could be grown. Mark even heard one self proclaimed expert claim that vireyas were as hardy as maddenii rhododendrons. They are not. Nor are they as easy to grow well in the garden as many of us hoped. In fact as we go through the process of winding down the nursery, vireyas are the crop that we most often agree we will not be sorry to farewell out of commercial production.

Don’t get me wrong. We are vireya aficionados. They are a wonderful family of plants and we would not be without them. Our association with vireyas goes back to the mid 1950s when Mark’s father collected a form of R.macgregoriae in New Guinea and brought it back here to Tikorangi. In those days border control was considerably more lax. That plant still survives in the garden here and mass flowers every year without fail. It was the start of a father and son plant breeding dynasty which has seen more than twenty five different hybrids named and released on the market over the years and is still continuing.

Vireyas are deceptive because they are very easy to put roots on, as we say. In other words, even home gardeners with no special facilities can have success with cuttings (although the aforementioned saxafragoides may be a challenge). They grow quickly (except for saxafragoides). Because they come from the equatorial areas where day length is pretty standard all year round and seasons are not defined by temperature change, they don’t have the set growing season that other plants show. So if plants are relatively warm, they will put on growth spurts most of the year. They also have the endearing habit of flowering randomly and often over many months. Indeed some are almost never without a flower and if you have enough plants in your garden, you can pretty well guarantee something in flower for twelve months of the year.

The down side is that they have pathetically little root systems and even well established plants can up and die on you when your back is turned. Being sub tropical, they are frost tender (any touch of frost will burn them and more than about three or four degrees of frost will kill them). With such small root systems, they are also extremely vulnerable to wet conditions and many soil fungi can take them out.

Readers who have lost vireya plants will be heartened to hear that it may not be their gardening skills at fault. In nursery production, we have always had a better cuttings take on vireyas than any other production line. But from then on, it is mostly an up hill battle. We always have a much higher death rate in the finished crop of vireyas than any other plant line we have grown over the past twenty five years. It can be very disheartening going through and pulling out the deaths. And we work harder to get bushy, well shaped plants than any other plant line. I figured this year that they are easily the most under priced crop we grow and were we staying in production, I would want a much higher wholesale price to justify the effort.

Compounding all this is that, of course, it is the highly desirable varieties which are the hardest to keep alive. Many if not most of the fascinating species are difficult. The named hybrids with big, luscious, scented trumpets are also more vulnerable whereas the utility toughies are more reliable but less coveted. Ain’t that always the way?

If you want to try taking vireya cuttings, select a stem of new growth which has hardened sufficiently to be firm. Make a clean cut across the base and then take a sliver off the outer green stem layer for about 2.5 centimetres from the base on two sides. It is very important to take it on both sides because this is where the roots are formed on vireyas. Reduce the cutting to two leaves only. If you have rooting hormone, it will increase success but you can manage without it. Stick the cutting in potting mix and place it somewhere warm but not in direct sun. You can cover it with a loose, clear plastic bag or a cut-off plastic PET bottle if you want to keep it warmer. Keep the potting mix damp but not saturated. You may see roots forming in about six weeks or so but they are best left undisturbed for three or four months.

Well grown vireyas are a delight and a great addition to the garden. But as a plant family, they are just not quite as easy and bullet proof as some of us hoped back in their hey day. They are great container plants and excellent for people who like to make a fuss of their plants but are certainly not an easy care option for the garden in the way that their hardier cousins are.