Sunday, September 30, 2012

The spring blues

I do not know what it is about the colour blue, but it seems some people just cannot get enough of it in the garden – including the Head Gardener.  In fact, the first garden we made in our first shared house featured a blue and gold garden that was named after her beloved maternal grandmother.  It featured a few of her favourite plants, a few of which we also grow in our garden here.
One that did not feature in that first garden but is a feature of our garden here is a blue Corydalis, one of those unusual beauties that combine the ferniest-looking leaved with subtle blue flower I have seen described as “curious shaped”.  They certainly do have unusual shaped flowers, long tubes of mid blue, topped with white.   The first of these to become very popular in New Zealand was a variety called ‘Pere David’, named after the great missionary plant hunter.  There are lots of others varieties around, but they are all variations of the same theme – attractive filmy foliage, often with a silvery cast, topped with cool blue flowers.
These are natural woodland plants, and do their best in light shade, although I have seen them doing superbly well out in the open in gardens at the Dunedin Botanic Garden.  Either way, they need moist soil with good drainage to be seen at their best.  Although the blues are the most commonly grown varieties nowadays, there are other colours – yellow, white, pink and maroon types can be found, with the yellow and cream varieties perhaps being the strongest growing forms.
We have some forget-me-nots growing in the same bed as the Corydalis – no one could pretend that these are precious and delicate plants, but the softly-hued powdery blue flowers are surely as pretty as any.  They can certainly get away a bit, seeding with abandon, but they are such a pretty soft blue, and they are easily enough weeded out.
There are improved strains around, which are mainly smaller and more compact in growth while retaining the same blue flowers.  They look great in bedding situations but I think the taller varieties look better in the garden.
If you like forget-me-not flowers there are a number of similar but slightly different species and strains around.  I am a great fan of the lovely silver foliaged Brunnera ‘Looking Glass.’   This is one for the open garden with relatively large leaves of a shiny silvery hue, and makes a wonderful foliage statement in the perennial garden.  But at this time of the year, it has a bright bonus – masses of bright blue flowers, not large but carried in good numbers.  I have this in rich moist soil and it does very well, increasing nicely.

Sunday, September 23, 2012

As much as I love the arrival of spring with its attendant lift in the spirits as well as a rejuvenation of the garden, I also dread the arrival of the grass growing, and hence lawn mowing season.   The once-fortnightly ritualised scalping of the remaining green areas around the house becomes a more regular chore until it peaks at about a four to five day interval, then tapers off again as we approach summer.
You might sense that I am not a great lawn lover.  For me, they are a slightly annoying requirement to help set off the gardens that I am really interested in.  Over the years here, I have removed one lawn entirely and embarked on an insidious programme of slowly reducing the size of the others by making extra gardens, then widening them.  I think the lawns probably take less than half the time they used to take when they were at their full extent.
My lawns are not in great shape either.  I do try to keep the broadleaved weeds down (more about that in a second) and I spray for Onehunga weed, but in reality my lawn, like the vast majority of lawns is a MDW lawn – mowed down weeds.  It is a mix of various grasses, clover and any other low growing weed that can cope with being topped regularly.
I do spray the lawns with a selective weedkiller at this time of the year –I managed to get it down this weekend, taking advantage of the fine, calm weather. My primary aim to keep the Onehunga weed under control, as nobody likes having their bare feet attacked by multitudes of prickles in the dry summer months.
Onehunga weed is a real pest when it gets established in a garden but it can be controlled relatively easily if look after at the right time of the year. It is an annual that has small ferny leaves growing about 20 cm across, with tiny greenish-yellow flowers. It starts to grow with the first rains of autumn, but doesn’t really kick on until spring when it flowers and sets many seed heads.  It is a bad problem in Wairarapa, because it flourishes in dry summer areas – as the grasses die back in our usual summer drought, it provides room for the Onehunga weed to germinate and grow.  When the seeds are almost mature they are easily picked up and spread by animals moving across the lawn – especially, it seems, bare-footed children.  It is important to get some spray onto these weeds before they have set seed as the plants are harder to kill as they get older, and of course the seeds have already been set.  If you have any of these weeds in your lawn (they will also grow on other bare patches in the garden) it will pay to get onto this job straight away.
I generally use a product I used to know by the trade name of Faneron, although nowadays it is packaged as ‘Prickle Weed Killer’, which I guess is a simple enough name to remember.  This year, though I used a combination product which will also have a lash at the broad leaved weeds like dandelion, hawk bit and the like.  I usually just spend an hour or two each spring forking the worst of these out, but I decided to try the easier option this year.

Sunday, September 16, 2012

I was wondering around the outer streets of Masterton the other morning, relishing a day without too much wind and rain.  As always at this time of the year, my head was filled with gardens, because a stroll through suburban developments is an intriguing glimpse into people’s gardening fashions and passions, and is also an interesting history lesson in the sense that some gardens canbe very accurately dated by the plant palette that has been employed.
I could not help notice the number of very bad native gardens there are.  Some of them date back quite a while, before the more recent craze for indigenous planting, while others are newer.  Where these gardens fail (in my opinion of course) is that they do not appreciate that they are gardens, human constructs, not some bizarre attempt to make a fake New Zealand landscape.
In its worst manifestation, this style of garden is composed of lots of sedges, long past needing to be divided and replanted, some very scruffy looking New Zealand flaxes that have not been tidied since they have been planted, and a splattering of untrimmed Coprosmas, that have completely outgrown their allotted spaces.
But, I am delighted to say, there are also some inspiring gardens that are largely composed of natives and have been built in such a way they work as gardens, and still others where native plants have been cleverly incorporated into a wider planting.  Once combination was so clever and attractive I came back home to get my camera to take some photographs, and it was simplicity itself – a puawhananga scrambling through a red flowered manuka.
The puawhananga is the plant pakeha called the native clematis (there are others that we will get to soon!) and botanists call Clematis paniculata, and is undoubtedly the most beautiful, and also one of the most vigorous of the native clematis.  It can be found growing through forest margins and in bush land throughout New Zealand – there were plants in flower on the Rimutaka Hill road when I p[assed over recently – and is reliably hardy, although it can be hard to get established.
Like all the New Zealand clematis it is dioecious, a flash way of saying it carries male and female organs on separate plants.  This matters in the garden where we are looking for bigger flowers generally, and most of the varieties you can buy in the garden centre will have male flowers.
It is very difficult to transfer these plants from the wild.  They scramble along in the upper branches of shrubs and trees, and they flower a long way away from their roots.  To make things more complicated, the plant goes through a number of different plant habits too, making it hard to track back to the main plant.  On top of that they deeply resent being moved as well so you are best to buy a plant from the nursery.  .
When you bring C. paniculata into the garden you must remember to plant it the same say it grows in the wild.  It is a true forest denizen and needs conditions similar to its natural habitat - a cool root run, preferably in humus-rich soil, and good moisture.  It should be planted where it can clamber up a medium sized tree for best effect, as in the garden mentioned above where it was spreading from a three metre high manuka into a similarly sized cabbage tree.

Sunday, September 09, 2012

Howling winds, scudding showers and slowly warming temperatures – must mean spring is just about here and it is time to start thinking about getting the vegetable garden kicked back into life after the slower winter months.
Despite the lousy weather I managed to get out into the kitchen garden for brief spells over the weekend, and pulled a few weeds.  I noticed the garlic and the shallots have made a great start with sprigs of leaves pushing through.

I spent a bit of time in the glasshouse too, mainly checking on my Iris seedlings, and the ungerminated Iris seed from Australia (they will germinate in the next few weeks).  It is very noticeable that the temperatures are rising in here too, and the once-weekly watering that sufficed over the winter will no longer do the trick and I will have to check on it most sunny days from now on.
The soil in the vegetable garden is in surprisingly good condition considering the rain, but we are very freely drained here, and I guess those who have heavier soil will still be wondering when they can get onto it.  It is very important not to work up soil if it is very sticky feeling, as it will help destroy the soil structure, and as we discussed last week, it is vital to ensure the best possible structure to the soil.  For gardens that are not cultivated often just adding some mulch annually will do the trick, but if you are turning the soil over frequently it is important to think about the way how you keep it healthy. 
I like to use home-made compost, and I try to dig in a good dose each year, but well-rotted animal manures will do the trick just as well, and some combination will probably work even better, as each component will have different mineral strengths.  If you are adding home-made compost it usually pays to add lime at the same time, as cropping tends to lower the pH of most soil and compost usually has low pH as well.  You can use a very fine horticultural grade, which will be released quite quickly, or you could get coarser agricultural grade (which is usually cheaper) and which will take a lot longer to release and thus can be applied at a higher rate but less often.
I managed to give my garden a bit of a going over the other weekend – just a rough digging really – so it is ready to have a final working up and then I can start planting some spring vegetables.  It is far too early to start thinking about frost tender summer-cropping plants like tomatoes and peppers yet (unless you have a glasshouse, in which case it is a good time to start with tomatoes especially) but as the soil warms up we can start planting and sowing some of the green-leaved types in particular.  Cabbages, cauliflowers and broccoli, those cousins from the brassica family, should be well under way by now, but if you want to sow your own, there is still plenty of time to be doing that. 
Sowing and growing your own seedlings is a very economical way of doing things, of course.  It affords you the chance to grow a wider variety of cultivars and also means you can control the number of plants you buy at each stage of the planting season.  It probably also means you can grow just the particular type of seed you want rather than being restricted to the varieties your garden centre was to supply you.
When you go to buy seed you will probably be shocked at the discrepancy between the varieties on offer.  Older varieties, which are open-pollinated, are relatively cheap.  More modern varieties, produced by keeping two separate strains alive and then crossing between the two (called F1 hybrids) are much dearer.  In most cases it is worth paying the extra and getting the Fq1 hybrid seed, as it will almost certainly be stronger growing, will fruit earlier and will give a much sturdier product.  I think this especially applies to tomatoes and peppers – I would even think of growing an old open pollinated type of these.  

Monday, September 03, 2012

A lot of rot - in a good way

One of the aspects of gardening that newcomers and young people in particular struggle with is the idea that any kind of cultivation depletes the soil of its natural nutriments, and that intensive gardening of any kind requires keen attention to soil fertility and structure.
For some kinds of landscape gardening the process of growing plants and allowing them to die naturally and return to the soil will keep things more or less in equilibrium – woodland gardens can be treated this way, and many native gardens will also function perfectly well in this manner.  But if we are constantly removing vegetation from the soil and not replacing it – as we do when we grow bedding plants in the same soil year after year, or in an even more pronounced way, when we establish vegetable beds – then we need to think long and hard about how we treat the soil.
One of the things we can think about is returning the spent vegetation from the garden back into the soil, by recycling it through a composting system.   Young people, used to the ‘garbage in, garbage out’ concept in computers (where bad data into the programme results in bad computing results) are always amazed that there is a natural system where ‘garbage in, brown gold out’ is the rule!
The value of well composted material is two-fold.  Compost returns valuable nutriment to the soil, in the natural forms of the valuable chemicals plants need to function – nitrogen, potassium and phosphate in particular.  It also functions as a valuable way of restoring humus to the soil, ensuring the soil structure is maintained or enhanced leading to a better fauna of microscopic animals that help break nutriment down, and also helps aerate the soil, meaning roots will develop better and more efficiently make use of the increased nutriment available.
Having decided upon a compost system, how does the tyro composter get underway?
Firstly, choose a receptacle for your compost.  There are many containers that will suit, including plastic bins, wooden crates, and even simple cages made from chicken wire.  The optimum size is probably about a metre square, and they should be placed away from the wind, sun and rain so you can control the moisture level in the bin.  Also make sure you place the container on soil rather than concrete – you are going to be relying on soil critters to make their way up into the bin to do the work for you.
Now you can think about what can be composted, and fortunately there is a wide range of suitable material – lawn clippings and leaves from the garden, as well as fruit and vegetable scraps, tea leaves, and coffee grounds are all useful.  You can also improve the way the system works by adding thin layers of animal manure or seaweed, and alternating with coarse layers of straw or the like.  You can also use sparing portions of wood ash.