Tag Archives: Tikorangi: The Jury garden

Plant Collector – Acer griseum

Acer griseum - it's mostly about the wonderful bark

Acer griseum – it’s mostly about the wonderful bark

Mention maples and most people think of the fresh spring foliage, the burgundy lacy look of some patio maples all summer and the glorious autumn colour. It is all about the foliage but not with Acer griseum which has nondescript green leaves all summer. No, it is primarily about the bark.

Often called the paper bark maple, Acer griseum is one of the best ornamental bark trees in the world. The old bark peels back in shiny, curled layers to reveal a matt skin below and it is all in glorious copper tones, often described as cinnamon in colour. The sight of light glowing through these bark curls is nothing short of magical and it is a visual delight which lasts all year.

It comes from Central China and it was not introduced to the west until the turn of last century, 1901 to be precise. It was clearly an immediate success because within 21 years, it had been given an Award of Merit by the Royal Horticulture Society in the UK. While it will get some height, maybe 8 metres over time, it remains generally narrow in form so doesn’t take up much space. The bark starts to show within 3 or 4 years of planting. Apparently it will colour up much better and put on a good autumn show of scarlet in cooler climates though I can’t say I have ever noticed it colour here.

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

Plant Collector: Syagrus romanzoffiana

The towering Queen Palm, or Syagrus romanzoffiana growing in coastal Taranaki

The towering Queen Palm, or Syragus romanzoffiana growing in coastal Taranaki

I asked Mark how tall he thought our queen palms are. Mentally I was stacking 2 metre men on top of each other which is how I estimate tree heights. “About eighty feet,” Mark replied, “to the top of the crown.” I leave it in imperial feet because it sounds more impressive than 25 metres. They are tall, these handsome palms, and we have three of them. All were planted in the late 1950s by Felix Jury, from seed given to him by one of the Australian botanic gardens. Not that they are an Australian native. These are South American palms, coming from that mid band where Argentina, Brazil and Bolivia meet.

The single trunks are tall and slender and the impressive top knot houses an entire condominium of nesting birds. In spring time, there are often small, lightly feathered corpses at the base because fledglings are not going to survive a fall of that magnitude. It is mostly sparrows with the occasional starling. We often sit in a spot which looks out to one palm and the amount of comings and goings are prodigious.

I read advice on line that said: “the fronds die early and must be pruned to keep the tree visually pleasing”. No, we do not get the extension ladder out to groom our queen palms. Fronds do indeed die but they detach themselves in time and crash to the ground. As the sheaf of the frond is quite substantial, you don’t want special plants beneath and you certainly wouldn’t want one of these beside a building or near the car.

S. romanzoffiana is a suitable substitute for the common bangalow palm. While there are reported incidents of it escaping into the more tropical wilds of Australia, it has nowhere near the weed potential of the bangalow and we have never heard of it being a problem in NZ.

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

Garden lore

“What is a weed? I have heard it said that there are sixty definitions. For me, a weed is a plant out of place.”

Donald Culross Peattie, (1896 -1964).

Weed plants
After my recent faux pas with Lilium formasanum, I was contacted by Carolyn Lewis, the national coordinator of Weedbusters, an organisation with support from many interested parties, dedicated to raising awareness of the problem weeds in this country. Too many of these are garden escapes and gardeners need to take some responsibility for unleashing vegetable time bombs. The website http://www.weedbusters.org.nz gives extensive information on individual weeds including how to eradicate each species in your area and useful suggestions of alternative plants to use instead.

Weedbusters are not covering the plants included in the National Pest Plant Accord (which are the banned ones) although there is a link through to the Ministry for Primary Industries section on these agreed pests. Some of the inclusions surprise me (Bartelttina sordida for one), others don’t. The arum lily, aristeas and agapanthus are widely recognised as problematic. I would have liked to have seen more information on where these plants are problems (national, regional or specific to just one area) because one region’s weed can be another region’s valued garden plant.

Without becoming too paranoid, take notice of those that seed down too freely or spread rampantly in your domain. If they are popping up all round the place, threatening to invade well beyond their allotted space and choking out other plants, or are extremely difficult to eradicate then you are probably looking at plants with significant weed potential for your conditions. While purists may advocate total eradication, in some cases we choose to manage such plants. We don’t want to be without our campanulata cherries that feed the tuis but we take responsibility for the seedlings and are vigilant weeders. The vegetable garden is not exempt either. We rated strawberry spinach as downright dangerous and went for eradication.

We don’t need more weeds in this country.

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

Plant Collector: Cyclamen hederifolium

???????????????????????????????
As early as January the first flowers on Cyclamen hederifolium start to appear on parched soils, though they are just coming into their own now. Some of you may know C. hederifolium by its earlier name of neapolitanum. It is the easiest of the dainty species to grow with one of the longer flowering seasons. The heart-shaped leaves, usually mottled and marked with silver, appear towards the end of flowering and make an attractive ground cover through until early summer.

Hederifolium comes in a range of pinks from light to mid, as well as in pure white. It hails from southern Europe through to Turkey and grows in hard, poor conditions, tolerating both heat and cold. What it doesn’t want is wet ground. We use it in open sun to semi shaded woodland margins where drainage is good.

Cyclamen grow from tubers which can develop to large, flat discs. Over the years, some of ours have reached up to 20cm or more across.

If you can’t find C hederifolium for sale, it is easy to grow from fresh seed and gently seeds down in the garden. If you know of somebody who already has it, the seed forms later in the year as a fleshy capsule at the end of a corkscrew stem. The secret is to sow it immediately and not try and store it.

The species cyclamen have a gentle charm which I personally find lacking in the big flowered hybrids which are sold as house plants. However most of those will survive as garden plants and live on if you find a suitable spot where they won’t get outcompeted by overhanging plants.

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

Banned plants in New Zealand

The offending Lilium formasanum

The offending Lilium formasanum

I have to start with a mea culpa today. Last Friday I featured Lilium formasanum on Plant Collector. I wouldn’t have done so had I known it was on the Pest Plant Accord list. In other words, it is banned from propagation and sale in this country.

To be honest, we are a bit surprised it is on the banned list. While it seeds down, in our experience it does so gently and has never shown invasive tendencies here and it is not strong enough to out-compete native plants that we can see. However, we respect the spirit of the Pest Plant Accord and I would not have praised the merits of this lily had I known.

Being on that list, does not mean it has to be eradicated – just that it can’t be produced for sale and that gardeners should be cautious with it. My general advice is that if you live near native bush or a reserve and certainly near a national park, the responsible action to take is to get rid of these plants from your garden altogether. In more suburban areas, it is not likely to be a problem but keep an eye on what they are doing and don’t let them escape. You also need to be careful what you do with garden waste because too many of our weeds are garden escapes.

So embarrassed was I at having been caught out making a public slip-up that I started to browse the National Pest Plant Accord booklet, the website of the Ministry for Primary Industries and some of the regional council websites. After encountering some of the most confused and badly designed websites I have seen in a while, I rang our local pest plant person to confirm my interpretations. There are no simple answers and there is a wonderful level of inconsistency in language, classifications and recommendations. It is all as clear as mud really. So here is my attempt to translate it to home gardener level.
???????????????????????????????
The handy little spiral-bound book entitled the National Pest Plant Accord is a listing agreed to by various bodies including the Nursery and Garden Industry Association of NZ. You can request a copy of this booklet from the Ministry or your regional council. It has photos and descriptions (one plant per page) but no advice on dealing to individual plants – every page tells you to contact your regional council for this advice. The plants included are a little… random, shall I say. Lilium formasanum is there but I don’t know where it is a particularly problematic weed.

Curiously, Rhododendron ponticum is also included. Now, R. ponticum is a blue rhododendron species that has been used extensively to breed many of the big blue hybrid rhododendrons favoured by gardeners. It is a real problem in the UK where it has established itself in the wild by layering and seeding but I am not aware of it ever being produced much, if at all, in the nursery trade in this country because the hybrids are so superior. The hybrids are not a problem. In other words, ponticum is not a problem in this country but it could be if we let it get established. Well, if this Pest Plant Accord were to include every potential weed in the world that could establish here, it would be a massive tome.

We have not cut our bangalows out at this stage, but we are alarmed at their weed potential

We have not cut our bangalows out at this stage, but we are alarmed at their weed potential

But the Accord misses out on some significant plants because the nursery industry has dug its toes in and refused to play ball. I have written before about the bangalow palm (Archontophoenix cunninghamiana) which we regard as having significant pest potential, and we are not alone in that opinion. Similarly the Chinese Windmill Palm (Trachycarpus fortunei) is pretty questionable but so strong in the trade that it may never make the Accord. We’d say the same about the Himalayan Daphne bholua too.

The problem with the Accord is that it is national and what is a significant or major weed in one area, may not be at all problematic in another. That is where the regional councils come in. As far as I know, their pest plant lists are not dependent on cooperation from the nursery industry and being based on local experience, they are more relevant to local gardeners.

In Northland there are huge issues with seedling campanulata cherries and I have been told that only sterile varieties can be sold there now. Similarly Buddleia davidii and agapanthus, but they are not on the national Accord. Taranaki completely bans both species of the giant Chilean rhubarb (Gunnera tinctoria and manicata) and insists on total removal.

Waikato Regional Council has lists on its website though you do have to know the common name (often confusing) because apparently it is too complicated to list under both botanical and common names on the directory page. Plants are classified as eradication (Council will deal to it for you), containment (landowner’s responsibility), potential pest and merely nuisance status (presumably waiting to move up the ranks). There is information on how to deal to these plant pests. A quick look suggests that not many of them are common garden plants (though we will be getting rid of our yellow flag irises here), but it is worth having a look.

I just can’t help but think that some analytical thinking, better writing, consistency of information and good website design would make this stuff a whole lot more useful for responsible gardeners. These are important issues but the powers-that-be haven’t made it easy to use the information.

The days are numbered here for the yellow flag iris

The days are numbered here for the yellow flag iris

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