Sunday, February 22, 2009

Summer Clematis

I always say I am the easiest person in the world to buy a present for. Any kind of garden voucher or book voucher will suit me fine. Those who know me really well might even be able to work out what sort of garden plants or books I would like.
The Head gardener knows my tastes better than anyone, so I was not surprised that she returned from a recent trip to Taranaki with a book or two – albeit rescued from the sales table at the Inglwood Public Library. As well as a novel or two, there was an interesting book on the cultivation of Clematis, written in Australia.
I grow a few native Clematis species, and have grown some of the more popular garden varieties, but there is an amazing number of hybrids available, most of which I have never grown.
I am keen on some of the autumn flowering species and varieties, but there is a problem with some of them – they have delightful fluffy seed heads which convinces everyone that they are the dreaded (and mis-named) Traveller’s Joy, C. vitalba which has become such a pest in our native forest lands.
One of the best of these is the delightful yellow-flowered species, C. orientalis. This, in its best forms, has butter yellow flowers that nod on the end of stiff stalks. It flowers from about Christmas time, with spluttering of flowers through until autumn. At the same time silken flower heads are forming, providing a nice contrast.
This species is quite energetic – it can grow about eight meters in a season – but looks great when grown among dark-leaved trees. It is deciduous, losing its leaves over winter, when it can be trimmed back.
I have grown the similar looking C. tangutica, although it is not in our present garden. This also has small lantern-shaped flowers, lighter yellow in this species. This is sometimes called the orange peel Clematis, although that common name really belongs to C. orientalis.
Again, this flowers from about the New Year, and later flowers will be held among the silken flower heads. These heads will stay safely on the plant until the winter winds and rains destroy them.
Both the above are very hardy and will cope with anything our climate throws at them. They should be planted relatively shallowly – do not plant and deeper than the mark in the planter bag – and make sure you keep them well watered while they are being established. Once safely away they require no special looking after.

Sunday, February 15, 2009

Dirty confession

I have a dirty confession to make – I have some Montbretias in my garden.
This is a shameful thing to admit because Montbretias are a pest plant in many parts of New Zealand. Their ancestry in damp and warm areas of South Africa has allowed them acclimatise to New Zealand conditions with startling rapidity.
At this time of the year river banks splashed with burnt orange can be found all over the country. Last year, when I walked the length of the Ruamahanga River, I found wild samples of these weedy corms in big patches along the river, coming across my first clump underneath the first road bridge across the river at Mount Bruce.
Since then I have found clumps further into the hills, but still alongside streams, indicating their method of dispersal - they move along in the floods and when they find themselves stranded on the banks, put down roots and set up home, eventually starting a family who, in turn, migrate downstream.
Montbretias are in fact Crocosmias – Montbretia is an old fashioned and osolete name. They are native to south-eastern South Africa, and are mostly winter deciduous bulbs. They are members of the vast iris family, with flowers that look a little like an orange or yellow Freesia when seen up close.
The problem plant in New Zealand is the hybrid Crocosmia x crocosmiiflora, first bred in France in the nineteenth century. It has been extensively developed in England, when it is a popular garden plant. The English winters make this a slightly tender treasure in all but the southern counties.
There are some non-invasive species and hybrids suitable for New Zealand gardens. The one I grow in my garden is C. masoniorum ‘Lucifer’. As you would expect, this has bright red flowers, and has received awards in the United Kingdom. It is popular all over the gardening world.
There are other varieties available. Well-regarded English plant breeder Alan Bloom (yes, I know his name is a pun!) breeds many perennial plants at his Bressingham gardens, and he has been playing with Crocosmias. The wonderful butter yellow ‘Jenny Bloom’ has recently been released in New Zealand, and is a variety to keep an eye out for.
If you do have a patchy of the weedy forms, do your best to get in under control, especially if it is on a waterway. Small clumps can be dug up, but larger ones are best treated when they are growing strongly, with a dose of Round Up or something similar.
This great image from the University of British Columbia webiste

Wednesday, February 11, 2009

Watering in time of drought

My dear old Auntie Molly, who died last year in her nineties, was right on the button about climate warming. On one of my visits to her there was a lull in the conversation, and being the experienced conversationalist she was – she was in her nineties, after all – she told me she did not believe in global warming.
I was initially surprised that a ninety-something year old should hold an opinion on the subject at all. I quickly assumed she meant that she was a sceptic on the matter.
She proceeded to put me right, telling me the problem should be thought of as climate change, not global warming, as some places were going to get colder and some places were going to get warmer. And some places were going to get warmer in summer but colder in winter.
It looks pretty much like she was right. We have been having record high temperatures, while our northern hemisphere cousins freeze under record cold temperatures.
Those of us who garden on the eastern coast of both New Zealand’s main islands are going to have to gradually rethink the sort of gardens we aim for, and make some alterations in the plants we grow. We are fooling ourselves if we think we are going to be able to continue to irrigate as though there is a never ending supply of water for our horticultural needs. Councils are going to introduce more stringent watering restrictions, and societal tolerance for those who water outside those rules will be zero.
So what do we water first when watering is restricted?
When prioritising plants for water, make sure you protect reasonably recently planted trees and shrubs, especially those in exposed, windy positions. Mature trees and shrubs will have a much more extensive root system, and, as such, will be far better able to cope with a water deficit. Keep an eye on such plantings though, as they will still be prone to water stress if the drought continues long enough. Fortunately such trees will normally show early signs of being under stress. Their leaves will wilt, perhaps even drop, when they are water stressed.
Make sure you follow a few other sensible guidelines when watering any trees and shrubs.
Do not water the leaves – it is a waste of time and water. Trees cannot absorb water through their leaves, and much of the water thrown in the air is wasted through evaporation. Instead water at ground level, and make sure you water to a depth of 30 cm at least, remembering to water inside the tree’s drip line.
It is also important to keep an eye on the rate of water application – too fast and the ground will not be able to absorb the water and it will run off. Water slowly over a long period, so the flow of water gets deep down to the trees roots. Watering for short times only encourages shallow rooting which can lead to more drought damage. Do not be tempted to dig holes in the ground in an effort to water deeply either. This dries roots out even more and causes more damage.

P.s. photo courtesy Iowa State University - thanks folks!

Wednesday, February 04, 2009

Lake Onoke Spit

I am still on leave so took the chance to go visit the other end of the Ruamahanga River today – the Lake Onoke Spit, the barrier between the waters of the Ruamahanga system and the sea, on the shore of Cook Strait.

The Lake Onoke ‘spit’ is a mixed sand and gravel barrier beach that has formed by concurrent processes of marine sedimentation and tectonic uplift. In the process it has impounded an embayment to form a shallow coastal lake, Lake Onoke.
Mixed sand and gravel beaches are uncommon shorelines types and the examples that occur in New Zealand are internationally significant. The shallow coastal lake and gravel barrier system is one the largest of its kind in New Zealand and its relatively unmodified state makes this feature an outstanding example of its type.
I was expecting to find the colony of Caspian Terns that my friend Colin Scadden has been documenting for many years, but I saw no sign of it. I was accompanied by Black Backed Gulls at times, and saw a few shags, oyster catchers, dotterels, and a group of four gannets, swooping along the shoreline, parallel to the coast.

There were signs of visitors, including this shelter which has probably been constructed over the summer.

The spit is partially colonised by plants, including the lovely nihinihi, Calystegia soldanella. Those of you who are gardeners will recognise this as a member of the convolvulus family. It does not grow naturally inland, so I assume it is frost tender.

In many New Zealand coastal places Hare’s Tail Grass, Lagurus ovatus, is a common component of the flora – here on the spit it has made one or two extensive lawns, which look quite pretty in late summer when the seed heads are full.

On my way back along the spit I found a fish - but the birds had found it first!

Monday, February 02, 2009

Chamberlain's Creek and beyond

Today is the first anniversary of the day I started walking down the river. As I am on leave, I celebrated by walking up into the bed of the Ruamahanga from Roaring Stag hut, venturing further upstream than I have ever been.
It is about a 150 minute climb up and over a steep hill from Putara to get into the river at Roaring Stag, and then another 75 minute clamber to get as far up the river as I went today. The river gradually gets narrower and, at the place I stopped, it is in a gorge. I even walked past the dreaded Chamberlain's Creek, the most dangerous little creek in the ranges according to some. Looked calm with summer flow, of course.
I did not need to swim on any of the pools, but I would not venture past the point I finished at without a party to help.

I have talked to others about the last remaining section of the river – and none of my tramping friends have ever been into the upper gorge, which suggests it is not a place for the fainthearted, and perhaps not a place for a nature-loving bushwalker – much less a 56 year old one.
Time will tell whether I am spurred to clamber up to Cattle Ridge, for example, and then drop down through untracked country into the southern arm of the river, then out through the two upper gorges.

Sunday, February 01, 2009

As gay as a row of pink tents

The Head Gardener has a theory about my passion for small bulbs and rock plants. She reckons the plants I like have such long Latin names that I have to have labels that are larger than the plants. I think the final straw for her was the pretty little annual American daisy I grew – called Haplopappus phyllocephalus. I told her the first name meant “happy” (or at least sounded like it) and the second part meant “head”, so she should just call the plant “happy head” or “smiler”.
Some plants, though, have names that reflect their nature perfectly – although it is not always intentional. Take that flamboyant climber, the Campsis. Its name comes from a Greek word for “something bent”, an allusion to the curving stamen, but the flowers on this vigorous climber are as camp as a row of pink tents. Perfectly named, if you ask me.
There are only two species of Campsis in the wild, both Northern Hemisphere climbers of woodlands. They are strong growing plants and need a little bit of care in smaller gardens, but in an area where they can be allowed to grow almost unchecked, they will flounce about with gay abandon, giving an amazing display of orange or yellow flowers during the hot months of the year.
Despite being woodland plants in the wild, they will grow well in full sun, and free draining soil. Remarkably, they are very tolerant of salt winds, so they are a popular plant for the seaside.
They can be pruned rigorously if their natural exuberance needs controlling.
A suburban garden near my first garden had a remarkable example of this. It featured Campsis growing up some verandah poles. Each winter, when the plant lost its leaves, the owner used to trim the whole plant back to the stems. Each spring it would bounce into growth again, and flower profusely over the summer, before being trimmed back to its bare state in winter.
You do have to be a bit careful about digging around the roots though. If you cut a root you will have a new plant or two – a great easy way to propagate if you are a nurseryman, but a potential nuisance in the garden.
There is another potential problem with this plant. It is a self-supporting climber. It produces aerial roots which cling to branches or netting – but they will also work their way into masonry, so do not plant these climbers against a brick wall.
The two most common forms seen in New Zealand are ‘Madame Galen’ and ‘Guilfoeyli’ and I have sent hem described as C. radicans, and also as forms of the Chinese Trumpet Vine, C. grandiflora.
They are actually both varieties of the hybrid between the two species, C. x tagliabuana – and I am sorry about the Latin name again. The “tagliabuana” bit comes from some well-known Italian gardeners, the Tagliabue brothers, who first crossed the two species.
‘Guilfoeyli’ is an Australian raised variety with panicles of about ten orange-red trumpet flowers through late summer, while ‘Madame Galen’ has flowers more in the orange-yellow range.
There is also a lovely yellow form of the species C. radicans, sometimes seen – it is nowhere near as common – called ‘Flava.’ The flowers are smaller than the hybrids, and its seems the plant is a little less vigorous.