Sunday, July 21, 2013

A thought for my peonies

'Coral Charm'

Last weekend, when the weather was at its worst, and it was windy and raining heartily, I went down to my local garden centre to choose some peonies.  Not unsurprisingly, it was very quiet and I was able to take my time and look through the racks of packets on the shelves.  I was excited to see what a good range of varieties is available nowadays, but I did catch my breath a little at the prize of some of the newer forms – they were over $30 a packet.
I am used to looking through catalogues from various bulb growing firms and I am quite accustomed to seeing daffodils and irises reaching these sorts of prices, but their value quickly diminishes and a variety that was selling for $50 one year will be down to $5 within a decade.
Not so for these peonies – although the types I was looking at were certainly relatively recently introduced, they were also all at least twenty years old.
At first I was a little taken aback, but then I thought of how long-lived peonies are, and quickly came to the decision that I would still buy a few varieties as part of a revamp of a couple of flower beds out in the back garden.
The site I had in mind is absolutely perfect for peonies as it is both sunny and well drained in a bed that was originally part of a vegetable garden, then used for lining out bearded irises.  Over the years it had had a lot of compost added to it, and thus it is deep and fertile soil, soil that is ideal for peonies.   Although it seems counter-intuitive, peonies can still do quite well in relatively infertile soils, as long as it never becomes water-logged.
It is quite important to make sure peonies do not have too much competition from nearby trees and shrubs, as they do not cope with that at all.  In fact, they can even throw in the towel if they are under a lot of overhead foliage.  I suspect the flowers might also be a bit troubled by botrytis in that situation too.
When you buy plants at this time of the year you are getting divisions from larger plants, and will usually get some roots that look very much like the rhizomes of a bearded iris, with large buds about 3 cm long, and coloured bright pink.  It is quite important to plant these correctly as they can fail if planted too deeply or shallowly.  Unlike bearded irises which need to be planted on the surface of the soil so they can creep along in the sun, these plants actually need the rots to be slightly buried.  But they should not be planted too deeply – if they are planted too deeply the buds will be insulated from the winter chills which induce new growths.  The ideal depth is for the bottom of the new buds to be about 5cm below the surface. 
You do not need to add any fertiliser when planting – in fact it can be counterproductive as it may damage the new buds – and, despite their long-lived reputation for needing super-fertile soil, they are not gross feeders, and probably do not need a lot of supplementary feeding.  We have a large specimen of the pale pink, late-flowering form ‘Sarah Bernhardt’ which is grown in a mixed perennial border and has done fine for the past fifteen years without any extra feeding, and has slowly increased in size.

Some people think peony is slightly coarse, but I have no problem with my plants – I just plant other summer flowering plants around them, and their admittedly unexciting greenery is hidden for the summer.  It is important that you do not cut the foliage down straight after flowering, in the way you might with daffodils for example (you shouldn't really do it with daffodils either!) as it will stop any plant growth.  Instead, wait until the autumn, when it will slowly turn yellow and die off naturally.  I always cut the old, dead foliage at that stage and compost it.  If you wanted to, you could give the plants a quick spray with fungicide at that stage but I have never felt the need.

Sunday, July 14, 2013

Cyclamen surprise

Cyclamen coum

There are plenty of plants that have lots of variety, with multicoloured forms and a variety of different plant shapes, but sometimes it is the singularly unchanging plants that capture out attention.  At this time of the year it is the humble cyclamen that grabs me, despite the inescapable fact that all cyclamen species follow the same basic shape, and they are really only available in white and pink, with a little variety thrown in with modern hybrids – purple and other shades that are not found in the wild being added.
And at that point I suppose we had better start making a distinction.  In most gardeners’ minds there is only one type of cyclamen, or perhaps two at most, and they are the florists’ cyclamen, early winter flowering plants that are very popular around Mothers’ Day.  In fact, when we owned the bedding plant nursery we grew these plants by the thousand, both traditional large-flowered forms, and the more recent miniature varieties.
In the wild there are about twenty species of cyclamen, although you would probably have to be a botanist to differentiate between them.  Just one species, C. persicum, has provided the basis of the florists’ cyclamen, but in the hundreds of years of selective breeding within this species, a wide range of forms has been selected, and the cyclamen now represents great value as a winter pot plant, providing many months of colour for a relatively cheap price.  For a price of about $10 you can have flowers in the house for months on end.
There are just a few tips to growing these plants as potted plants.  The first is that they need good drainage, but at the same time they like moist soil, so it is important to make sure they are in moisture retentive soil but not sitting in a saucer filled to the brim with water. When watering, make sure you water the soil and not the corm, and also ensure you let the water free drain. It also pays to water early in the day for two reasons; firstly, to allow the water to soak through the plant, and secondly, to let the corm dry out again before the evening.  If these steps are not followed the plants are a little prone to mildew.
When growing potted plants inside it also pays to be a bit canny about light levels as, cyclamen do best in bright indirect or curtain filtered sunlight – if they are exposed to direct, hot sunlight they will probably develop burns on their leaves.

Like most potted plants, it pays to give the pots a little feed every now and then especially if you are looking to retain them for more than one season.  The easiest thing to do is to apply a liquid fertiliser on a regular basis – perhaps once a fortnight. Remember to put this on in the early part of the day, and try and avoid the corm.

Once the plant has finished flowering there is no reason to discard it -  you can either plant it in the garden in a shady spot that is protected from frost, or you can put it in a cool spot for the summer months, reducing the watering, and then re pot it in fresh potting mix next autumn for winter.

Smaller and certainly less well-known are the dwarf species, found throughout the Mediterranean area. The best known of these is the diminutive ivy-leaved species, C. hederifloium, which is sometimes seem naturalised in extensive swathes in large gardens, its carpet of shining white and soft pink flowers always looking stunning in later summer and early autumn. I have grown this in pots in the glasshouse, along with its slightly less hardy cousin, C. africanum, which has marginally longer stems in my experience.
Among the other forms I have grown is the lovely winter flowering C. coum, with rounded leaves, usually deep green, but sometimes marbled with silver, and in some special strains, pewter coloured. The flowers, which are slighter stumpier than other species, are usually pink, of varying shades, with a deep maroon blotch at the bottom of each petals. 

This species is quite hardy – it is naturalised in parts of Great Britain, so should be perfectly fine in New Zealand.  It is also reasonable able to look after itself in the garden.  I grow moist of my small cyclamen in the glasshouse, not because they are not hardy, but because that way I can get too see them easier, and can appreciate their beauty better. Like all cyclamen species, they set deed readily, contained within a capsule that sits just above soil level, but is spring loaded.  When the seed is ready the seeds are rapidly dispersed, and germinate where they land, meaning I have pots that end up with more than one species.

Over summer my iris seedlings are grown underneath the glasshouse benches, each 100mm pot holding a separate seedling.  Imagine my surprise and my perplexed expression when I discovered some C. coum growing in the iris beds this winter.  I can only assume they must have been dropped into the seedling pots before they were planted out, and have germinated in the potting soil when it was placed into the iris beds.   

Sunday, July 07, 2013

Hebes out front

The combination of the week’s mild weather (despite it being the middle of winter) and a bit of time at home, led me to have a wander around, looking at what is happening in the garden.  As it is still very early in the season I was surprised to see a number of spring flowering bulbs out in flower. The tazetta narcissus (that most people call jonquils) are out, but as they can flower very early I was not shocked, but I was very surprised to see the little green and black flowered snake’s head iris, Iris tuberosa, in flower, at least a month early.
A clump of hyacinths I planted in the autumn was in flower too, the pale yellow ’Yellow Queen.’ I suspect that this might be a case of an imported bulb breaking cover early, and that it will revert to its usual flowering period next year.
I also had time to look at a couple of shrubs that I knew needed trimming or removing.  One was a seedling kohuhu, Pittosporum tenuifolium.  It was a lovely small-leaved form, with a shimmering silver colour, but it had grown up through the lower branches of a semi-mature Magnolia grandiflora, and was rapidly growing to be a nuisance, and really had to come out.
The other problem was of a smaller nature – a dwarf dark-coloured Coprosma, whose growth ambitions outgrew the space I had allocated for it. It was also very free with a crop of berries each season, and as such also had a crop of seedlings each year.  I am not normally too worried about seedlings appearing among my plants (it’s a natural consequence of using lots of mulch among shrubs) and often keep and propagate the seedlings I find, but not in this case.
I was very keen to add another hebe to the number growing in this bed, as they have proven to be very reliable in what is a difficult site.  The previous owners had altered the front of the house, and had added truckloads of soil.  Unfortunately it is of very poor quality – very much clay-based and sticky in the winter.  On the summer it dries out badly, and forms great crevasse-like cracks, and most shrubs struggle to grow in it.  However, hebes, of various stripes, have managed to cope with the soil, and in the main they have thrived.
 I planted a scattering of cuttings from the strongly coloured ‘Wiri Prince’ a few years ago, and they have flourished.  This is one of Jack Hobbs’ Auckland-bred hebes, but seems very hardy here and quickly forms an upright, evergreen shrub reaching at least 1.5 metres high. The rich violet-purple flowers are mainly carried in summer to autumn, but the shrubs seem to have a flower or two at most times.
We also have a plant or two of the deep rose pink flowered ‘Wiri Charm’, which is a very tidy growing form (tidier than ‘Wiri Prince which needs to be trimmed annually) and grows to about a metre high, forming a dense shrub.  ‘Wiri Cloud’ is smaller, with crisp green leaves and pale pink flowers.  This one makes an interesting alternative to a box hedge.
We also have a number of the grey-leaved species, as I love the foliage contrast they offer.  Perhaps the best of these are the form of Hebe albicans known as ‘Red Edge’, and the stunning (and very well-named) ‘Quicksilver.’ ‘Red Edge’ is descended from a species mainly found in the mountains of Nelson province, and is very hardy.   It has a compact growth habit with a grey leaf of its parent species, but its point of difference is the pinky-red edge around the leaf. In summer the foliage colour intensifies giving the shrub a pinky hue. 
‘Quicksilver’ is a form of H. pimelioides, with an open arching habit. The small grey leaves, each with a red edge, contrast well with the dark branches. The flowers are small and light blue-mauve, carried in the early summer, and although they are attractive, it is the foliage that is the winner with this plant.