Scents and sensibility

The Head Gardener and I took advantage of the warm weather at the top end of the weekend to go for a stroll down to the Kuripuni village for lunch.  It was very pleasant walking along in the sun, looking at the gardens and noticing how much spring has moved along in the past few weeks.  At one garden we stopped to look at a shrub growing over the fence line with wonderful racemes of chartreuse-yellow flowers.  The Head Gardener looked at me and said “That’s it, that’s it!”

I must have looked a little puzzled, as she gently reminded me that I had failed to identify a plant she had come home and asked about.  A work colleague had been given a bouquet which featured what she had described to me as “Lily of the Valley flowers, but from a shrub”. I knew she would not have meant the shrub usually called the Lily of the Valley, the Pieris as we have a couple of them in the garden.

At the time I just could not picture what she was walking about, but I really ought to have thought of this lovely shrub.  It is Stachyurus praecox, a deciduous plant so it has gone out offavour a little but it has a lot going for it, with a charming display of flowers in the spring before the glossy coppery-brown leaves unfurl.  At this time of the year it is very valuable for picking, the colour seeming to go with most colours, especially the golden colour we associate with daffodils and Forsythias.

There was another attraction in a garden a few houses down the road and I could not quite work out what it was at first.  A beautiful scent was drifting over the footpath – heady and sweet and fruity all at the same time.  I thought it was perhaps Daphne, but then I thought it was a bit sharper than that. When I had a closer look through the shrubbery I was astonished to see that it was a mix of at least three different scents, all within the same small garden.

Against the wall was a trimmed specimen of that charming semi-deciduous charmer, the hybrid Viburnum x burkwoodi. It is undoubtedly the most popular of the scented Viburnums in New Zealand, with tight clusters of pure white flowers at this time of the year, carrying a soft fragrance that I have seen described as being like that of baby powder – certainly less heady than Daphne. It has nice green foliage in the spring but grows a little sparsely and can look a little straggly until it is mature.  Clipping will help that but you need to be careful as if you clip it too hard you will knock the flowering back as well.

The semi-deciduous behaviour it shows is understandable as it is a hybrid between the evergreen V. utile and V. carlesii.  The former is a rare species in New Zealand, and I have never seen it offered, probably because it is not very attractive, but V. carlesii is usually findable and is a very fine deciduous shrub. It grows to about two metres and at this time of the year is covered with the most delightful pink-budded flowers, opening to white, and scented even better than V. x burkwoodii in my opinion.  You will find this in garden centres at this time of the year and it is well worth seeking out.  It always reminds me of my old gardening friend Henry Carle, who used to write this column when I was first interested in gardening, and who encouraged me over the years.

A lot of rot

I was working out in the garden on Sunday morning, getting the first of the spring flush of weeds out of the way of the daffodils, hyacinths and irises, and as I often do on Sunday morning, catching up with the National Radio programmes.  There was an interesting discussion about the costs of recycling, and the presenters briefly covered the amount of green waste that goes to the recycling centre.  In some councils’ case it amounts to about 50% of the waste stream, by volume.

New gardeners and perhaps quite a few of us “oldie” gardeners as well, have not realised the economic advantages of composting, quite aside from their advantages to the soil profile.

The activity of growing things uses up the humus in the soil, and depletes some of the soil’s fertility.  In the wild there is a never ending stream of humus and nutriment being returned to the soil in the form of leaf litter, but in our gardens that does not happen.  We harvest our crops – whether that be grass on the lawn, flowers in the house garden or vegetables in the kitchen garden – and often forget to return that goodness to the ground we are working with.

The chemical value of the nutriment, the nitrogen, phosphorous and potassium can be replenished by applying commercial fertilisers, but these products, useful though they are, do not restore the humus levels – to do that we need to return organic matter to the soil.  We can pay the recycling centre to do that, by paying to take it to the centre, and then later on, purchasing the processed compost (and I do that sometimes) but it is easier and more efficient to manufacture your own compost at home.  As well as improving the soil fertility and structure, compost aids the micro-biology of the soil, nourishing a wide variety of life from earthworms down to microscopic bacteria, and as it improves the structure of the soil it also aids in improving the soil’s ability to retain moisture, reducing the need to water so often.

I run a system with four plastic compost bins (a bit of an anachronism but there you go) as well as a large open-formed bin.  My large bin is built against a strong fence, with a buffer of chicken wire to stop leakage, and chicken wire fencing on the two sides.  The front is composed of slats which can be lifted, enabling me access to get in and dig out the compost when it is made.

When I start to fill one of the bins I like to put a layer of twiggy material at the bottom, to help provide the sharp drainage that is so necessary for the bins to work properly.  I always keep some of these when I am pruning in the garden, and have a little heap alongside the bins for when I start a new batch.

When you make your new brew it is important to keep a mixture of ‘greens’ and ‘browns’, the greens being types that are full of nitrogen while the browns tend are high in carbon and also tend to have more fibrous material.  The obvious ‘green’ is the weekly catcherful of lawn clippings but also includes kitchen food scraps, fruit peels, coffee grounds, tea bags, and chopped weeds.  Make sure not to include any of the bad weeds in your mix – you do not want to go spreading convolvulus or oxalis through the garden

‘Brown’ material includes straw, dried leaves and twigs, sawdust, wood shavings and wood ash (all from untreated sources) and  egg shells.  I like to have a few bales of pea straw around all the times, as they are the perfect ‘brown’ material, although by the time I get to use them they have started to rot down and almost become ‘green’!

Well-made compost is made from a mix of organic materials containing both 'green' and 'brown' materials, usually applied in layers of about 100 cm thickness.  I find I always have a steady stream of ‘green’, with clippings, garden waste and kitchen scraps, but the ‘brown’ stream is harder to reliably source, hence the straw bales.

Mount Inspiring

This week is Conservation Week and the local Department of Conservation office has arranged some fun activities out at Mount Holdsworth, including frisbee golf and geo caching.  If you are unfamiliar with the latter sport/activity it is sort of like hi-tech hide-and-seek, with treasures secreted away at GPS locations.

You might be wondering what such activities have to do with gardening - apart from all the above being great fun of course. The answer is - an awful lot actually.  The DOC officers are also offering a couple of walks - one along the banks of the Atiwhakatu River and the other up the Gentle Annie  track up to Rocky Lookout, and if you are looking for gardening inspiration you could do worse than take the time to partake in one of these strolls.

I try to battle my way up to the top of Mount Holdsworth a couple of times each year, partly for exercise but also because the varying gardens you pass through are a constant source of inspiration.

Let’s assume you have a small garden and cannot think of establishing a piece of suburban beech forest, and you are going to think more about some of the smaller growing plants you will find on your trip in the forest.  One of the first plants you are likely to see is the stunning white flowering native iris, Libertia.  These are great plants for the home garden, coping with varying amounts of shade and flowering with abandon usually.  I am fond of the graceful L. grandiflora which has more arching leaves and large flowers.  The more common L. ixioides has stiffer leaves and smaller flowers, but it seems to cope better with full sun.  There are a number of yellow coloured forms of this species that are worth growing for their foliage alone.

Just once I found a nice clump of the diminutive L. pulchella growing on a damp bank just this side of Rocky Lookout.  It only grows about 100mm high, but spreads widely when it is happy in a moist site.  This is available from specialist nurseries - the other types are much more commonly found in garden centres.

 Among the other herbaceous plants to be found at lower levels on the mountain are lovely blue berried turutu, Dianella nigra.  At this time of the year this plant will be looking a little like a small flax, with arching green leaves.  It will soon have tiny white flowers are followed by bright blue berries in summer.  These are usually deep blue but I have seen some light blue forms in the forest at Mount Holdsworth. 

One of the most common ferns growing in association with Dianella is the stunning Crown Fern, Blechnum discolour. I think this makes one of the most amazing garden-like scenes on the mountain, as it appears in large clumps at various along the tracks, looking like a garden carefully constructed by a high priced landscape consultant.   The fronds are dark green but at this time of the year the new young fronds are starting to unravel, their lighter and brighter stems looking like a cluster of flowers in the centre of the fern.   The fronds can grow up to a metre long, and when well suited the plant will eventually form a small trunk. 

I think this looks at its best when it is massed planted under trees, just the way it grows in the wild. It is often available in smaller grades making it economically feasible to be used in this manner.  I even have a cluster of them growing among my iris seedlings in the shade of a Magnolia tree.

Parsnips beet carrots

My expressed intention of not planting any potatoes this year turned out to have been hollow – a week after I told everyone I was not planting any I found myself looking at the remains of last year’s crop and thinking – “The ‘Rockets’ have sprouted really well “and I succumbed to the temptation and planted short row of both ‘Rocket’ and ‘Desiree’.   They will be ready to harvest in time for Christmas, which will make the Dunedin-based son happy, as he had made comment when he rang for Father’s Day.

I spent the afternoon of ‘Father’s Day’ in the garden, well togged up because it was quite cold.  I was mainly working in the flower beds, as there were a lot of weeds germinating and I like to get them out early, but I also made the time to do some work in the vegetable garden.  It is important to get the garden ready for spring at this time of the year, and as soon as the soil is dry enough to be worked, it is a good idea to get any fertilising and composting needed under way.

The first thing I did was to shift the carrot bed.  We find carrot rust fly to be a problem, and nothing chemical has worked for us.  We were almost at the stage of giving up growing carrots when we decided to try a bit of physical exclusion, firstly by using a large white shade cloth covered cloche, then by using small wooden walls around the edge of the carrot patch.  It does not need to be very high – 100mm would probably be enough – and it does certainly help.  The theory is that the fly comes in at ground level, so an obstruction stops the fly getting in to lay the eggs that later hatch and cause the unsightly damage to the carrots.

Soil preparation is very important with carrots.  They need fertile soil, but do not like fresh manures at all, so it is best to plant them in soil that was prepared for a leaf crop the previous year – brassicas or lettuces perhaps.  If you want to add a fertiliser, any good general one will do the trick, but you could also consider one of the slow release types as well.

If the rust fly has been a problem, try and sow as thinly as you can, as the flies will hone in on the scent of the thinnings, so the less you need to thin the better.  I did not sow any seed this weekend – I want the bed to settle down a little – but it is the right time to put the first sowing in.  I like to mix the seed up with some sand as it helps sow more thinly.

There are many different varieties around but I think it pays to try and find some F1 seed if you can – it is quite a bit dearer but the crop is more reliable and the crop is hearty.  We grew a purple variety the year before last, which was great fun, but to be honest they were not the best croppers, and I do not think we will be doing that again.