Category Archives: Abbie’s column

Abbie’s newspaper columns

Why viburnums send a shiver down Mark’s spine

Viburnum plicatum 'Roseace' - pretty as a picture

Viburnum plicatum ‘Roseace’ – pretty as a picture

In times gone by, we used to retail plants from here seven days a week for much of the year. My Mark was a reluctant retailer at best, though his plant and gardening knowledge is immense and he was perfectly capable of giving good advice if he liked the visitor. Alas, too often he would comment wryly: “That was one who put the cuss into customer”. He certainly never subscribed to the view that the customer is always right.

The mere mention of viburnums sends a shudder down his spine, even after a fair few years. A couple came in asking for Viburnum plicatum ‘Mariesii’ which they had seen growing in a prestigious garden. Mark checked that they understood this was a white lacecap variety and they assured him they knew what it was. Turned out they had no idea at all. Some time later, when the plant came in to flower and was not the common white snowball bush, the husband dug it up from the garden, put it in a supermarket bag and brought it back wanting a refund. He’d probably only paid $15 for a big plant of it. It was of course correct to its descriptive label (we take pride in such matters) and a fine specimen but it just wasn’t what he thought it would be. It is a bit like opening a packet of lollies, tasting one and then expecting to return the open packet many weeks later because you didn’t like the flavour.

I felt sure ‘Mariesii’ should be in flower for me to photograph – it is a beautiful big white lacecap flower on a large shrub with fresh green, pleated foliage and it tends to grow in layers like a cake. Mark and I agreed we must have it planted somewhere. We just can’t quite remember where. That is the problem of a big garden lacking records. It will have to wait in anonymity until we stumble over it again.

What started me thinking about viburnums were two plants which are looking particularly striking this week – ‘Roseace’ and one with the difficult name of V. sargentii ‘Onondago’. It took me a while to commit the second name to memory.

‘Roseace’ (sometimes ‘Rosacea’) is the pink form of the classic pompom viburnum, which is usually the form known as V. plicatum ‘Sterile’, or the Japanese snowball. It is a sport which was sold widely two decades ago and it forms a large, deciduous shrub to over 2 metres tall with an abundance of pretty, peachy-pink snowball flowers. That is at its best. Being a sport, it can revert to the more dominant white. We found this to our cost when we propagated a fair number from our main plant and then had to wait until they all flowered because only some of them came pink. Mark went through the original plant and pruned out all the white sections a few years ago but I see it is rather patchy pink and white again, though nevertheless very pretty and showy.

V. sargentii 'Onandago'

V. sargentii ‘Onondago’

‘Onondago’ is different, being narrow and upright. Its fresh spring foliage comes out deep maroon and lacecap flowers (like flat hydrangea blooms) have the tiny fertile flowers in deep red in the centre, surrounded by a ring of larger white sterile flowers. It is a selection out of the US National Arboretum in Washington and, being a seedling not a sport, it is very stable.

Viburnums come from a large family with over 150 different species identified. Most are from the temperate areas of the northern hemisphere so are generally hardy and are of the shrub/large shrub/small tree type. There are evergreen, semi evergreen and fully deciduous species. I am pretty sure it was the evergreen V. tinus I saw grown quite widely throughout Hamilton making a small tree that flowers in spring.

Balls of delicious fragrance from one of V. carlesii hybrids

Balls of delicious fragrance from one of V. carlesii hybrids

Earlier in the season, we had the somewhat short-lived delight of the waxy, fragrant balls of a couple of different ones. I am pretty sure they were ‘Anne Russell’ and x carlcephalum – both are hybrids from the Korean species of V. carlesii. We have them planted beside the driveway and the scent is easily as strong as a good daphne with more spectacular flowers, though their season is much shorter.

Most viburnums are very easy to grow, being not at all fussy about soils and conditions. They are a bit of an unsung hero, really, making good backbone plants which star when in flower and behave themselves for the rest of the year. Some of the deciduous varieties also give good autumn colour in inland or colder climates.

Just try and find out what you are buying before you plant it and don’t expect to dig it up and return it bare rooted because you made a mistake. Mark might have been more understanding over the ‘Mariesii’ had the customers been a little less know-it-all at the time of purchase. Instead he was intensely irritated, scarred now by the memory.

First published in the Waikato Times and reprinted here with their permission.

About tanalised timber in the veg garden…

Our bean frame - it's hard to avoid tanalised pine in the veg garden

Our bean frame – it’s hard to avoid tanalised pine in the veg garden

Living rurally, the stream of free farming newspapers descending into our letterbox seems never ending. I cannot say we read them from cover to cover, but it is surprising how much interesting material is in these publications. It was ‘Straight Furrow’ that yielded this week’s most interesting article. It was about a project looking for hard wood alternatives to tanalised pine.

The timber production of this country, based as it is on Pinus radiata, derived from a forestry project started way back in the 1870s, trialling various options. Clearly the pine was the stand out performer and work has been ongoing on selecting the best characteristics for plants which are to be commercially cropped. Modern plantation pine is a somewhat different tree to the gnarly old pines sourced originally from Californian and then Australian seed sources. The use of pine as a building material is a boon for what little is left of our native forests, though we are guilty of plundering the hard woods of Asia instead – especially when it comes to outdoor furniture and more upmarket decking.

The pine we use is grown very quickly and is soft as a result. To get any durability outdoors, it is treated by tanalising it in a solution that contains chrome, copper and arsenic. There is now a quest to find quick growing hardwoods as an alternative and some of the eucalypts look extremely promising.

What does this have to do with gardening? The impetus for this research was, apparently, the discovery of arsenic in the Marlborough aquifer back in 2003. In this case, it was not a cause for panic. That arsenic was occurring naturally and not a danger to health. But, as an aside to that particular study, elevated arsenic levels were found in the soils. These were linked to the use of tanalised posts. When you think about it, we use gazillions of tanalised posts in this country, many of them treated to an advanced level so that they are durable in the ground. There is a scary thought.

It appears that those readers who ask whether it is safe to use tanalised timber in the vegetable garden are indeed asking a valid question. It is pretty difficult to avoid when you think about it. The planks many people use to avoid compacting soil when walking between rows are likely to tanalised. The waratahs often used to stake tomatoes, the poles to build the bean frame… but especially the sides of raised vegetable beds. Yes, apparently these do leach toxic chemicals into the surrounding soil. And plants are very good at absorbing heavy metals, especially leafy greens like vegetables.

It appears that some within the wine and kiwifruit industries are very keen on non-tanalised hardwoods as an alternative. Both these producers have extensive need for wooden growing frames. Organic farmers and growers are also anxious.

I have not read that it has been proven beyond any doubt that anyone has suffered from ill health or death as a result of secondary contamination from tanalised timber. It is your call entirely as to whether you consider it is a risk worth taking. It appears that different people respond differently to chemical poisoning. An anecdote about somebody who lived to a ripe old age despite an extremely careless attitude to sprays is not proof of safety because it may be that the next person suffering multiple allergies is a result of very little exposure.

Presumably the leaching of chemicals from tanalised timber slows down as it ages, so if you are using some near edible crops, look for the old stuffveg.

Heart macrocarpa is probably the most suitable alternative to tanalised pine at this stage, though it will rot eventually. The eucalypt alternatives being researched are offering maybe 25 years without being treated but the research project has a way to go yet.

For the record, the article referred to is in the October 15 issue of Straight Furrow, page 11, headed “Hardwood project promises billions”, written by Jon Morgan. The sad point of that story is that they just missed out on $3 million dollars of government funding because they were not able to guarantee that the project would earn $200 million dollars in exports by 2030. It is a fairly sad comment on the nature of government funding for research. It seems an exorbitantly high bar to set for a modest contribution, but the project is continuing. Imagine some of our pine plantations replaced with eucalypts. That would change the landscape.

First published in the Waikato Times and reprinted here with their permission.

The merits of mulch

Homemade compost - our preferred garden mulch

Homemade compost – our preferred garden mulch

Mulch, dear readers, mulch now. Mulch well and you will be grateful later.

There are good reasons to mulch. In areas prone to drying out over summer, a good layer of mulch put on now will contribute to retaining soil moisture levels later. You don’t want to be mulching when the soils have already dried out because, equally, it acts as a barrier to stop water being absorbed.

Mulching also keeps down weeds and hugely reduces the amount of summer weeding that is required. There are two provisos. You need to clear the area of weeds first. Mulch won’t kill existing weeds. It just discourages germination of all those seeds lurking in the soil waiting to spring forth when the time is right. It also makes it much easier to pull out those that do penetrate through the layer. The second proviso is that you need to be using a weed-free mulch and many home compost mixes won’t have achieved that state.

Avoiding soil splash is another benefit. In areas of heavy rainfall (and some of us can get downpours akin to the tropics, albeit without the warm temperatures), bare soil splashes back up and this can spread disease amongst vulnerable plants. Soil splash also makes vegetables dirty. Mulch acts as a cushioning filter.

Depending on your choice of mulch, it can act as a soil conditioner and add valuable carbon content. Some will gradually break down as worm and microbial action incorporated it into the soil. Obviously this is only true for organic matter. We are big fans of organic mulches here, less so of inorganic options like limestone chip or gravel. But no matter what you use, a mulched garden looks better than expanses of bare soil. It is the experienced gardener’s not-so-secret weapon. You won’t find many good gardeners who do not mulch regularly.

So what to mulch with? Our number one preferred option is compost, homemade compost in fact. It does three jobs in one hit. It mulches, it feeds the soil so that we rarely have to use other fertilisers and it looks unobtrusive. But then we do not want a mulch that looks obvious. It is a tool, not a display in itself.

Leaf litter can be untidy but makes a good mulch

Leaf litter can be untidy but makes a good mulch

The second choice mulch here is leaf litter. We don’t waste any organic material. If it doesn’t get composted, then it gets raked into a back area to gently decompose and darken, before being raked back out around plants. Leaf litter can be untidy but it is good in less formal areas.

Then there is fresh wood chip. We own a good sized mulcher so we generate a fair amount of wood chip from the garden debris that is too large to go into compost. Calf shed shavings and sawdust also come into this category. When fresh, all these materials have to be used as mulch but not dug into the soil or they will rob the nitrogen as they break down. Laid on top and exposed to the elements, the decomposition happens slowly and naturally and should not cause problems. If you are going to use sawdust, just make sure that it is never, ever tanalised (you will poison your soils) and be prepared for a few months of a somewhat alarming orange appearance.

Old wool carpet and newspaper (weight the latter down) can be used as mulch if you don’t mind the look. We do mind, so we don’t go down that track. Just make sure the carpet is 100% wool and not synthetic and keep to newspaper – leave the glossies out with the recycling.

Pea straw may be a better option for the vegetable garden than the ornamental garden

Pea straw may be a better option for the vegetable garden than the ornamental garden

If you need to head off to the garden centre to buy your mulch, you will often find pea straw on offer. While this is a traditional mulch, if you are not in a pea producing area, consider its carbon footprint. It blows away unless you keep it damp. It is a myth that it helps fix nitrogen in the soil – that capacity is in the pea roots and all you are buying are the tops. Aesthetically, I think it looks fine in the vegetable garden (especially if it is all around high-producing strawberry plants) but I am less keen on the look in ornamental gardens. A bale should cover around 6 square metres of area.

Granulated pine bark is often favoured. Try and get it pre-composted. Compounds in the bark stop it rotting down too quickly so it lasts a surprisingly long time on top. It is a discreet looking mulch but it adds no fertility. If you have a big area to cover, buying it in bulk will save money. A cubic metre should cover around 15 square metres.

You need a layer of 6 to 7 centimetres to be effective. You will often see 10 cm recommended but that is pretty deep. Finally, try not to pile the mulch hard in on the trunks of woody plants. It doesn’t matter around perennials but trees and shrubs run the risk of collar rot.

The mulching effort now will reward you further down the track.

First published in the Waikato Times and reprinted here with their permission.

Better in theory than practice – planting street berms in edibles

Street plantings of orange trees in Cordoba

Street plantings of orange trees in Cordoba

I have been following with some interest the debate about Auckland’s road berms and the transfer of mowing responsibilities to the closest house occupants. I can’t think that I have ever lived anywhere with road berms that Council mows so my sympathy is limited for those who are railing against having to take responsibility. Road berms are community spaces that stop our urban areas from being too grey and congested.

The debate about alternative uses was more interesting. I was amused by the wit who suggested that a creative approach could solve the lack of new housing space in Auckland. Indeed, if you look at contemporary Japanese domestic architecture, I feel sure there is potential for space-saving apartments to be constructed on some of the wider berms. Though I can already hear the cries of protest from the adjoining landowners.

Often I hear the claim that berms should be planted out as community vegetable gardens and that all street trees should be fruit trees for the benefit of residents. It is so easily said and on the surface it sounds such a good idea but there are reasons why this is not so popular with powers that be.

Starting with the vegetable garden berm idea – how are you going to stop every passing dog from urinating on your plants? Or worse. Just watch a dog being taken for its walk and you may lose enthusiasm for growing vegetables out in a public space very quickly. Is the berm to be fenced to keep out wandering dogs? This rather defeats the whole notion of common space when ownership is claimed by way of a fence.

Unless your berm is at the end of a very quiet cul de sac, there are issues with automotive pollution, not to mention road splash. Okay, the lead content of our petrol has dropped dramatically from where it used to be, but I am not too sure about wanting to eat plants which are grown with full exposure to petrol and diesel fumes. And road spray on wet days is likely to be introducing more contaminants.

Then there are all the issues of ownership of the produce when it is on public land. How happy would you be if somebody came along and harvested your entire potato crop just as it hit its peak – or worse, before it has? And if one or two key individuals do not take ownership of the garden and manage it, soon it will descend into an unsightly mess which is a great deal worse than a bit of rank grass.

Vegetable gardens on the berms are not that easy. This is not to say it can’t be done, but it is not a universal panacea and it will take a lot more individual effort than mowing.

Plums - more likely to feed the birds than the human populace

Plums – more likely to feed the birds than the human populace

So, fruit trees as street trees? I really do not envy any Council staff who are faced with decisions on street trees but I applaud their valiant efforts to plant up our urban areas. Street trees have to be able to grow in exposed conditions, sometimes highly polluted. They need to have small leaves which decompose quickly so they don’t block all the drains. Their root systems are vitally important (don’t want to break up sewers or sealed areas but they need to be sufficiently well rooted not to blow over) and so is the ultimate shape of the tree. They need to be more upright than wide spreading. On top of that, if they are too desirable, they are vulnerable to theft when young and they need to be able to grow with a minimum of attention and no spraying.

That is a pretty big list already and that is just off the top of my head. There are probably more criteria than that. So tell me which fruit trees match those sorts of criteria. If it was easy, I am sure we would see it done more.

I have seen oranges used as street trees overseas – table oranges in Sorrento in Italy (tourist town, though, so maybe less inclined to be nicked) and bitter Seville oranges on the streets of Cordoba in Spain. The ones in Cordoba were harvested commercially, I found out. Citrus are not high maintenance trees but they still need spraying with copper and they are vulnerable to borer.

Feijoas! Definitely an option for road verge plantings

Feijoas! Definitely an option for road verge plantings

The best option I could come up with here is feijoas. They require next to no care and are reasonably wind tolerant. The fruit is peeled before eating so street pollution is not such a problem. Apples, pears, plums – all need care and are more utility than attractive. They are not even utility if they are uncared for and don’t crop. Plums are more likely to feed the birds than humans.

I think street trees are street trees. It is not a situation that lends itself to an ill-thought out philosophy that they should all be fruit trees in suburban areas as a matter of principle. I can only see it working where an adjacent householder takes responsibility for the trees and that includes dealing with theft and vandalism. It’s a nice idea in theory.

I admit, however, that I yearn to live somewhere with street plantings of oranges.

First published in the Waikato Times and reprinted here with their permission.

Low(ish) maintenance shade gardening

016 (2)It is clivia season here though it may not be clivia season for those who live in colder areas. Despite being much favoured by modern landscapers, these plants do not like more than a light touch of frost at most.

There are reasons why clivias are loved by landscapers. Of all the options for shady areas, they must be one of the most tolerant, forgiving and easy-care there is. For the better part of the year, they sit as a tidy clump of strappy foliage requiring little or no attention and when they flower in spring, the showy blooms last for many weeks. Plants can be left for years requiring no attention.

I looked at a photo of a property where the owners had used a reputable landscaper and the shady side of the house consisted of an access path with two narrow borders either side bounded by a solid fence. Both borders had been planted with clivias in single file, surrounded by bark chip as mulch. It is a very tidy, utility solution which, if the fence and path are smart, can even look stylish. If you like that sort of look.

Everything looks better with ferns, in my opinion. Ligularia reniformis.

Everything looks better with ferns, in my opinion. Ligularia reniformis.

Clivias are not a great choice for inland areas unless you are confident that you are frost free, which most of Hamilton and the Waikato won’t be. Sometimes such borders are beneath the eaves of the house and that will afford protection. But you will often see the same look achieved with, maybe, the tractor seat ligularia (L. reniformis), Ligularia ‘Desdemona’ or a similarly reliable, evergreen perennial.

It will come as no surprise to regular readers that it is not a look I favour, personally. While I can see the logic to keeping clean, crisp lines and some degree of simplicity, I just think it would look so much more interesting with the introduction of another one or two types of plants. They don’t have to be expensive or choice plants but what they add is textural interest, variation in height and sometimes the bonus of seasonal flowers.

Most gardens have a shaded area – at least that narrow side that runs alongside the bathroom and laundry and is on the other side from the sunny living areas. If it is a little-used area which is primarily access and has no house windows that look out to it, then it hardly warrants great expenditure of either money or ongoing effort. But a small amount of effort can make it so much more attractive and the beauty of shade gardening is that it tends to be much lower maintenance.

left to right: Helleborus x sternii, Francoa ramosa, pulmonaria, arthropodium (renga renga), phlomis, random fern and mondo grass - all cheap, reliable options for low maintenance shade gardening

left to right: Helleborus x sternii, Francoa ramosa, pulmonaria, arthropodium (renga renga), phlomis, random fern and mondo grass – all cheap, reliable options for low maintenance shade gardening

I headed out to the garden to look for options to add interest to a shade garden. There are plenty to choose from – just don’t choose them all if you want a clean look. Keep it to a maximum of three. Ferns. Pretty much everything looks better with ferns in the shade. They add a lightness of texture and detail of leaf to solid plants like clivias or ligularias and it is that contrast that can add interest.

Renga renga lilies are happy in more shaded areas and have the bonus of spring flowers. We have a lot of success with phlomis (P. russeliana or Turkish sage) with its yellow tiered flowers in summer. Similarly, the bridal wreath flower – particularly Francoa ramosa – is easy and obliging with summer flowers. The unattractively named lungworts or pulmonaria family combine very well with bigger, chunkier foliaged plants and add detail with their gentle variegation. Even common old mondo grass, be it black or green, can add a different texture. Helleborus x sternii is a reliable shade option with lime green flowers in winter.

If you keep to evergreen perennials which don’t require much more than an annual clean-up and which can be kept for several years without having to dig and divide them, you can make a low maintenance shade garden. Take care to plant them well in soil you have dug over, add plenty of humus or compost, mulch after planting and generally they can look after themselves.

It does not have to be expensive or difficult. If you can get simple combinations that are compatible, look good together, are happy in the conditions and meet the requirements of the gardener, it is a great deal more interesting than looking at a single plant variety en masse.

But that is the voice of a gardener, not that of a landscaper.

First published in the Waikato Times and reprinted here with their permission.