August 8, 2008 Weekly Garden Guide

Certainly in the north we are warming up noticeably and the grass is starting to grow again. While we will no doubt get a few more wintery blasts, when the sun comes out it is feeling positively spring-like. In the gardening world, this means that the pressure is about to increase exponentially to finish the winter pruning and clean up round.

  • Climbing roses get pruned differently to shrub roses. Tie in the long whippy growths for the first three years after planting and resist the temptation to prune them back. If you can undulate the whips along supports or train them more or less horizontally, it encourages all the side shoots to sprout and hugely increases the flower production. After three years, take out the oldest, woodiest stems and replace them with fresh green whips on a rotational basis. Prune back the side growths from the tied-in whips, to a few buds just as you do with wisteria. Climbing roses are not the easiest of subjects to prune and tend to be very vigorous but you may live to regret it if you fail to prune them hard.
  • Beware an explosion in weeds which is just about to happen. If you can stop this first seeding of the season, you will substantially reduce your workload later.
  • It is an ideal time for planting woody trees and shrubs. Put in now, they have time to establish themselves before the dryness and heat of summer. People on sandy soils which dry out faster, should take particular note.
  • It is time to be vigilant on slugs and snails again. These unwelcome critters will be multiplying up nicely and nipping off all your young shoots. Some intensive control now will reduce numbers later but you do not need to use slug bait like fertiliser. One bait can kill several. Digital control, beer and other environmentally sensitive approaches are also kinder to hedgehogs, birds and the odd suicidal family dog.
  • Container plants should be repotted every two years or so, especially if they are somewhat rootbound. It is a good time to attend to them now so they can settle in again before making spring growth. If you are intending to prune the roots to make them fit back into the same pot, then it is even more important that you do it without delay. Hose off all the old potting mix and make sure you prune the top of the plant to reduce stress. Slow release fertilisers were developed for container plants. We don’t recommend their use in the garden generally (there are cheaper, more environmentally friendly options) but we do use them in pot plants. If your plant is destined to stay undercover, halve the recommended rate of fertiliser to avoid burning the plant.
  • Early sowings will be starting in the vegetable garden – potatoes in warm areas, peas (pick an early cropping variety), turnips, carrots, parsnips, summer spinach and beet. A reminder that if you are buying asparagus divisions, you are likely to have more success with them if you get them established and growing well in pots before you plant them at the required 10cm plus depth in the garden. Asparagus is a bit of a long haul crop at the best of times (you will be waiting three years for the first harvest) and it is a permanent fixture so it is worth this extra effort and delay.

According to The Curious Gardener’s Almanac, over three quarters of all garden chemicals sold in Britain are for the improvement of lawns. It is likely to be similar here and that is a disgraceful situation when you think about it. Time to rethink attitudes to lawns.

Thinking Small in the Big Country

We had cause to travel to Australia a couple of weeks ago for a family celebration. Fortunately, given our timing, we were in Wollongong (south Sydney) and Canberra and our paths only crossed with the 125 000 Catholic pilgrims when it came to flying out of Sydney airport. We avoided the chaos of Sydney, which also meant we missed the Pope. But as I noted the austerity of St Peter’s Square and the near total absence of any vegetation in the Vatican City when I was there a month ago, I doubt that we would have been able to discuss gardening with him.

We have never been to Wollongong before and despite it being a somewhat industrial area, we were rather taken by it. Its location ensures a higher rainfall than many other parts of Australia and the climate was almost balmy. The soulangeana magnolias were at their peak (little sign of them showing colour here) and the presence of sub tropical plants, including an abundance of frangipani, indicates that the area never gets particularly cold. The beautiful blue sky and expanses of pristine beaches had us thinking that maybe Australia is indeed the lucky land. Certainly we did not hear the doom and gloom talk of home. Mind you, that may be a superficial judgement because the TV only showed wall to wall happy, smiling pilgrims.

After a tiki tour of the area which involved much bonding with her father identifying and discussing the multitude of exotic Australian birds, Elder Daughter drove us to her second home in Canberra. I have been to that city before but it was a first for Mark and he was a little shocked at the harshness of the climate. In winter it is very dry and very cold while in summer it is very dry and very hot. He whispered to me that he much preferred Wollongong. Gardening as we know it just is not possible in Canberra.

Daughter commented that none of the Aussie TV gardening gurus she has seen appears to have come to grips with practical design suggestions for front yards. The private courtyard out the back has been done to death, but there is a dearth of ideas when it comes to dealing with the waste of space out the front. Irrigation is on a semi permanent ban so the front lawn and garden does not survive. The only alternatives appear to be green nylon lawn (!) or dyed bark chip mulch (referred to as tan bark). Daughter was suggesting that if she had a front yard, she would be looking at buying a truckload of massive rocks and establishing a rock garden (more rock than garden). Or maybe try a meadow of anigozanthus (kangaroo paws) which, being native, might fare better.

Nylon lawn at up to $120 a square metre

Nylon lawn at up to $120 a square metre. Photo Abbie Jury

Post celebrations (no, neither a wedding nor a grandchild), Daughter and her partner indulged us by taking us to the somewhat remarkable Cockington Green Gardens which had possibly more than a nodding affilation to the genre of Fred and Myrtle’s paua house in Invercargill. No paua, but scaling hitherto unconquered heights of being twee to the point where it takes on a life of its own. It was started by a passionate Anglophile model maker and has recently been expanded with an international section (mostly sponsored by foreign embassies). Leaving aside the plethora of miniature scale buildings, cricket match, soccer match and all the rest of it (and there was a lot of the rest of it including fairy garden and miniature trains), the gardening was dominated primarily by dwarf conifers and clipped and topiaried buxus. Alas we can not get that excited about masses of dwarf conifers, but it was certainly clear that in a much colder climate the conifers colour up a great deal better. The silver blues and burgundies made our few at home look very subdued.

The Treaty House at Cockington Green

The Treaty House at Cockington Green. Photo Abbie Jury

New Zealand was represented by a model of the Treaty House at Waitangi. If I remember correctly, it was the only one not sponsored by the Embassy but I think by an individual instead, which may possibly be an indication that our ambassador to Australia has better taste. After our initial amusement, we were underwhelmed by the gardening at Cockington Green but envious of the evidence of large tourist numbers. Given that Canberra is hardly a tourist hotspot, it makes you realise how few we actually get in Taranaki.

Conifers and buxus and a toy train at Cockington Green

Conifers and buxus and a toy train at Cockington Green. Photo Abbie Jury

As an antidote to the OTT naff nature of Cockington Green, we headed off to the botanic gardens which are devoted entirely to native Australian plants with a purity of purpose which is not necessarily a populist position with locals, who may well prefer some bedding plants and colour. And the dry, open areas were a little arid with no underplanting at all. The hardy natural flora of Australia is nowhere near as exotic as their fauna and around Canberra is heavily dominated by hardy eucalypts. It wasn’t until we reached the bushland plantings that we went: oh yes. As New Zealanders, we take for granted our lush growth, both in the natural environment and in the contrived garden. It is a concept largely foreign to those who live in much harsher environments.

Mark was grateful for the relative absence of plant eating fauna at home. We would be less than impressed to have kangaroos peering out from the understory of the garden and effortlessly hurdling our fences. Possums here are a pest but at least we can shoot them – they are a protected species in Australia. The rosellas, vast flocks of sulphur crested cockatoos, crows and an abundance of other birdlife can wreak havoc in an environment where their main of source of food includes your garden plants. And at least we never got foxes courtesy of the British settlers. We saw tree ferns (yes, Australia has a range of tree ferns of their own) where the new growth had been stripped bare by rosellas in search of the spore.

There really is no place like home and the verdant green environment that we take for granted here is really quite rare. We would rather be here than there. They may be the lucky country economically, but we are the lucky gardening land.

August 1, 2008 Weekly Garden Guide

If your magnolia tree is opening misshapen and severely damaged blooms, the likely culprit is a possum which has beaten you to the tree and eaten out the centre of the bud.

Mark performs autopsies on all possums shot here and there are often one or two per season with stomachs full of magnolia buds. You have two alternatives – trapping or high velocity lead. It is usually only one that has discovered the taste treat so you don’t have to eliminate the entire population as long as you catch the guilty one.

  • Roses are starting to move. Don’t be panicked by that, but you are probably safe to prune now even in colder areas. Pruning forces the plants into strong new growth but by the time that happens, we will be nearing the end of August and the main risk of severe frosts will be over for most.
  • Lawn purists will be raking out the mosses from their grassy swards and dethatching the build up of residue from dead leaves. Certain grasses such as fescues do not rot down quickly and can build up a thatch over time. Bare areas can be over sown now. While you can feed the lawn at this time, most people will wait until the temperatures warm up a little.
  • If you feel your garden is lacking in winter interest and colour, look to the hellebores, cyclamen coum, the miniature narcissi (daffies) many of which are flowering now, snowdrops, early camellias and daphnes.
  • Nandina domestica Richmond is a stunner at this time of the year with its brilliant festoons of bright red-orange berries. If you have a plant which is not berrying, alas you have probably bought a seedling which may never berry. Give it a couple more years and if it fails to berry profusely, rip it out. Plant nurseries should know better than to sell nandina seedlings but it does happen.
  • In the vegie garden, prepare beds and plan. Planting season will be on us within a few weeks and it helps if you are ready to move straight in with ground that is already prepared.
  • The art of keeping garden pests under control is to get in early before they get established so the winter copper and oil spray of fruit trees is the single most important spray of the year. Ditto for roses.

While most of us dislike weeding, Clare Leighton wrote in 1935:

There is some hope in weeding, for the weeds may one day be defeated, but the tidying of a garden is as exacting and unending as the daily washing of dishes.

July 25, 2008 Weekly Garden Guide

Spring can not be far away. The earliest flowering magnolias are the campbelliis and already they have opened their first blooms. Check the trees in the Victor Davies Park next to the radio station on Powderham Street if you live in town. The campanulata cherries are just starting to break into flower for us which the tuis will be looking forward to. Another gardening year is about to start.

  • All this means that the pressure is coming on to get the winter pruning round underway – roses, wisterias, deciduous fruit trees, grapevines, many clematis and hydrangeas (the buds are already swelling on ours) are the main candidates for an annual winter haircut. Leave cherry trees alone (these get pruned in summer) and resist the temptation to be too drastic with late winter and spring flowering trees and shrubs or you will be cutting off their flower buds. We admit we have yet to prune our raspberries but they too should have been attended to by now. Cut off last year’s fruiting canes because the plant produces its fruit on new wood. Shorten the new canes to manageable height.
  • Take time to smell the daphnes. If you are planting daphne, they prefer to be out of full sun and in humus rich soil. Because they are winter flowering, they are usually best planted by pathways or entrances so you can smell them as you dash past under an umbrella.
  • If you have early potatoes in the ground, earth them up as they shoot so you are creating a mound. This is standard practice. It allows the soil to warm faster, kills the weeds, can protect emerging shoots from frost and gives a thicker layer to prevent the greening of the young tubers later on. You can plant potatoes any time now as long as you can protect them from frosts.
  • Peas, brassicas, silver beet and its allies, even an early sowing of carrot seed can be put in now. Broad beans can still be sown to give a late crop.
  • In the current wet spell, watch citrus trees for botrytis (the leaves go brown and fall off). You may need to give them a copper spray.
  • Roses and all deciduous fruit trees benefit from a winter spray of copper as part of the clean up round.

· Cora Lea Bell, who was presumably American with a name like that, wrote:

An addiction to gardening is not all bad when you consider the other choices in life.

Trouble with Buxus

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.

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.