A beautiful couple of days in New Plymouth for the weekend’s show – and the views of Mt Taranaki were gorgeous, both during the day and at sunset (not a given that the mountain will reveal itself in all its glory). I hope you enjoy some photos of the beautiful blooms on show.
The devastating fires ravaging Australia will have a huge human cost by the time they’re all over but there will also be an intangible cost to the country’s flora and fauna. While it’s well-known that fire was used for tens of thousands of years by Australia’s indigenous people as a method of land management, fires on this scale are unprecedented in recent history.
A 2012 report prepared for the Victorian Department of Sustainability and Environment, Response of Orchids to Bushfire, Black Saturday 2009, noted that the effect of the fire on orchids ran the gamut from being killed to being prompted to flower! Read a summary here, and find a link to the full report.
Unfortunately, the report notes that populations of Sarcochilus and other epiphytes were exterminated so we can expect that many wild-growing populations will be lost in these terrible fires.
Another researcher, working in South Australia, found that the timing of the fire may also play a major role in orchid survival – for instance, spring fires appeared to have a less detrimental effect than autumn and summer fires. See coverage of her talk here.
Although a fire may prompt seed release by some species, a resurgence of orchids does depend on subsequent grazing pressure (with fewer plants available, pollination is higher but grazing predation is also higher).
In a talk at last year’s Orchid Expo in Palmerston North, Australian orchid expert David Banks said there were 20 species of Sarcochilus in Australia (15 species and five sub-species), with some having quite localised and limited ranges. David has done much hiking as he likes to photograph native orchids in their natural habitat.
He posted on his Facebook page on Christmas Day that thousands of Sarcochilus falcatus have been destroyed by fire in the Mt Wilson National Park in the Blue Mountains of NSW, and there’s probably more bad news to come.
Often, when buying an orchid, a purchaser will ask about the plant’s growing needs and part of the reply will invariably be: It’s a cool-growing / intermediate / warm-growing orchid. But what does this actually mean?
Writing in the October 2008 American Orchid Society journal, Ken Slump sets out to make things clearer on this point and the text below is taken from that article, ‘Thermal Dynamics’. Note that all orchids need a drop in night-time temperature for blooming to occur.
Cool Growing: Cool growers are adapted to withstand cool season minimum temperatures as low as 10-13C and will not usually be harmed by 7C for short periods. Ideal warm season highs would be in the 15-21C range with tolerance for temperatures a bit warmer for brief spells. Think of these orchids as the citizens of higher and mountainous elevations within the tropics, some of which come from locations that are frequently shrouded in clouds and mist.
Includes: Cymbidium, Masdevallia, Miltonopsis, Odontoglossum, Sarcochilus, many Australian Dendrobiums, most Mexican Laelias.
Intermediate: This group does best with winter minimum temperatures in the 10-15C range. Ideal summer high temperatures would be 18-24C. Higher summer temperatures than these are usually well tolerated, particularly when accompanied by equally high humidity levels.
Includes: Cattleya (higher altitudes), Oncidium, many Paphiopedilum, Zygopetalum, some Laelias.
Warm Growing: These orchids thrive when winter minimum temperatures seldom fall below 15C. For best results their high temperature range in summer should be in the 21-29C range. Most can easily tolerate temperatures up to 32C but prolonged exposure to higher temperatures should be avoided. Most warm-growing orchids demand high humidity levels which can be challenging to maintain.
Imagine sitting under the dappled shade of a palm tree on a steamy tropical beach with a warm breeze coming off the water and you’ll have a good picture of what makes warm-growing orchids happy.
Includes: Phalaenopsis, Vanda, Cattleya (lower altitudes), some Paphiopedilum, many Dendrobiums, some Laelias.
Further reading:Orchid Culture in NZ by members of the Waitakere Orchid Club (2008). Opens as a pdf.
Of course, most orchids will survive temperatures well above or below their preferred range for a short time – these temperature group guidelines are targets to help growers produce healthy plants that flower well. It is difficult to list more than generalities regarding temperature preferences among orchids and variations often occur within a genus.
Some species might thrive in cool and intermediate as well as warm conditions, while another species could tolerate just one temperature range. There can be variation in temperature response among individuals within a species as well.
A bit of research should help you understand the climate each of your orchids comes from. In the case of hybrids, attempt to discover their species ancestry (for example, see OrchidRoots). Orchid hybrids are often more temperature tolerant than their species ancestors but may inherit a preference from one parent if large differences between them exist.
While it is frequently possible to maintain an orchid in less-than-ideal temperatures, you will find that plant vigour is improved and flowering enhanced when the minimum-maximum thermometer is carefully monitored and heeded.
Those members at our November meeting may recall my plaintive cry for help regarding a plant I brought along for the table display labelled Pleurothallis turantus. In preparation for the meeting I was trying to find out a bit more about the plant, which I’d purchased at our club auction earlier this year, and discovered that entering its name into Google brought up 0 results, not even a suggested alternate spelling (‘did you mean’…?).
It’s not often Google has nothing to say, which made me wonder about the accuracy of the label, hence my call for help at the meeting. Another member had the same plant with the same name also on the display table.
Getting the display table plant list ready for the newsletter made me go and double-check that I hadn’t copied down the label incorrectly. No, the small plant with its small, golden flowers was labelled Pleurothallis turantus.
Google had not changed its opinion of this plant name the second time I tried so I started looking for lists of Pleurothallis species, thinking that maybe the second part of the name had been a bit garbled by the label writer. Wikipedia has a major list, as do several reputable-looking websites. I knew it wasn’t Pths truncata because I have one of those (small, orange ball flowers) and Google images quickly revealed that Pths tarantula and Pths taurus were not matches.
So where and how do you look for an unidentified orchid? As a last resort I thought I’d try Google images, but could only enter a vague search term: ‘Pleurothallis-type orchid yellow flowers’.
Believe it or not, and I hardly could, there was a matching image on the first page of results – Physosiphon tubatus (syn. Pleurothallis tubata).
But wait, there’s more. Orchid names are slippery things at the best of times and this orchid has had a few in the very recent past. Simon Pugh-Jones, writing on the Writhlington School Orchid Project (WSBE) website in 2017 says:
“Some plants seem to change their name more than others. We first purchased this species in the 1990s as Pleurothallis tubata before changing it to Physosiphon tubatus to reflect changes in Pleurothallis, before changing it back to Pleurothallis tubata, then changing it recently to Stelis tubata and today checking with theplantlist.org we have changed it again to Stelis emarginata.” Read the full entry.
One local grower with plenty of expertise reckons there will be a good number of plants tagged ‘Pleurothallis turantus’ in this area. If you have one, please change its label!
If you’re like me and don’t have access to OrchidWiz (a purchased database), a useful online tool for checking plant names, and particularly good for hybrids, is OrchidRoots, now on version 3 and started in 2015 by Dr Chariya Punyanitya, a member of the American Orchid Society, assisted by her sister, Pim Little, and Emerys Chew.
The Bay of Plenty Orchid Society arranged a talk about deflasking orchids from Monika Simpson of Auckland and kindly invited Tauranga Orchid Society members along to yesterday’s meeting for what turned out to be very practical and useful instruction.
Orchids grown from seed are initially grown in a ‘flask’ in agar gel until they reach a certain size, which is when deflasking takes place (ie, bringing them out of a controlled environment into the natural environment of a home, shadehouse or glasshouse). Flasks are generally either clear glass bottles or lab-type flasks, which often have to be broken to remove the plantlets, or clear plastic bottles, which are cut open. Bottle-shaped flasks are used on their sides.
Monika, who was born in Poland, has quickly upskilled since 2016 when she first became involved with the sale of flasks imported from overseas and it was this experience that she shared with her audience.
One tip was to remember that plants in flasks imported from the Northern Hemisphere will need time to adjust to our seasonal cycle and, in fact, may not for the first season and you may see the plants go dormant in spring and summer.
“You should watch them and see what they want to do,” Monika said. “If the leaves are yellowing and dropping, let them go dormant and put them in a cooler, darker place.” This ‘adapting’ dormancy is generally shorter than normal.
“Leave them in the flask but watch for contamination. The flask will look horrible but dropped leaves won’t cause contamination.”
Is my flask ready to be opened? Usually, an imported flask contains plants already at the size for deflasking, but gauge it by eye: Look at the roots on the bottom of the flask. Are they strong and healthy with green tips? If it’s an orchid with a pseudobulb, have any bulbs formed? Have the plantlets grown since you’ve had the flask (remembering that Cymbidium plantlets will always be bigger than, say, Dendrobium plantlets)? If yes, then it’s likely time to deflask. Spring and summer are the best times to deflask.
If the flask has become contaminated (it can happen) and plants are dying an emergency deflasking will be necessary – but may not be successful.
How do I open the flask? There was more than one answer to this question. Lee Neale and Conrad Coenen like to unscrew the top just one twist and leave the bottle for a day or three, then half-untwist it and leave again before fully removing the lid and leaving again. This procedure, which takes 1-2 weeks, is to let the plants acclimatisate and harden a little before they’re removed.
Andy Easton (a New Zealand-born orchid breeder and grower now living in Colombia) moves his flasks to the area where the plants they contain will grow and lets them adjust to the situation before taking them out.
Monika, however, simply jiggles her plants away from the base end of the bottle and slices through the plastic with a bread knife. If using this method, prepare the worktop and have ready a bowl of lukewarm water, paper towels, sterilised tools, potting mix and a pot or several pots.
What do I do with the plants? Slide them into a bowl of lukewarm water and gently swish to release roots from the agar gel. If there is a contamination problem, Physan can be used in the water at the rate the manufacturer lists for orchid seedlings.
Andy Easton then leaves the plants on a paper towel and only pots on when the roots are white (dry). Monika pots immediately.
What’s the best potting medium? Monika talked about several media – she doesn’t use sphagnum moss, finding it hard to control its moisture content. “If it’s too wet, it’s also cold and will rot the plants. Once it goes crispy [dries out] it’s hard to rehydrate. Keeping it damp but not too wet is hard.”
She washes No2 bark (Kiwi Orchid Bark) the day before she wants to use it so it’s damp but not wet, and mixes this with perlite/pumice for potting. “The size of the bark is essential – No3 will create too many air gaps.” Conrad noted that mined NZ pumice will have too much zinc in it for plantlets so check the label before buying.
Monika also uses Fernwood treefern fibre, mixing it with No2 bark, and has had good results. “It holds the moisture but is also free-flowing,” and she finds it naturally warm whatever the ambient temperature. She uses two-thirds fern/ one-third bark.
What size pot should I use? The plants are used to growing closely together and appear to do best in a ‘community pot’ in their first growing season out of the flask. Monika uses clear, round plastic ‘bowls’ which aren’t too deep. She adds holes around the side and bottom.
“A transparent pot helps you see how much moisture is in the pot and whether there are any problems. If you can fit the whole flask into one pot, do it. The more plants there are, the more roots there are to absorb moisture.”
If the pot is deep, use large pumice or bark at the bottom and potting mix to the length of the roots and a little more. The chunky pieces at the bottom will also help drainage, which is crucial at this stage.
Where do I keep the pots? Monika has a heated growing house but for the rest of us, a mini-greenhouse has been endorsed by several members (like this one, available from Bunnings). Keep some water in the bottom for humidity and on hot days don’t forget to open the vents in the top.
When should I pot on? One growing season, including one winter, in a community pot is enough. Don’t overpot the plants when they come out of the community pot, although Monika admits it can be hard finding the right size pot for plants with stiff roots. She is using Dalton’s small square pots (2019 pot catalogue here) and has also used round hydroponic seedling pots (see here or here). The medium remains the same (No2 bark with whatever else you’ve used before).
Can I mount deflasked plants? Monika advises putting plants destined for a mount into a community pot first and let them grow new roots. “The roots from the flask won’t attach to the mount.” If you mount a plant in spring, she said the roots will attach in 2-3 months. She doesn’t use any media around the roots of a mounted plant and especially advises against sphagnum moss. “The roots will go into it to seek moisture but may become suffocated”. Any extra moisture they need (beyond watering) can be had from the air.
What are the most important things to know after deflasking? 80% of your success will be down to environment, Monika said. Even cool-growing plants need more warmth to start them off out of the flask. Water: Keep plants evenly moist as roots will not be adjusted to wet/dry. Fertiliser: Fertilise as soon as the plants are deflasked at half-strength. Roy Neale advises that any plants with a pseudobulb will be heavier feeders. Humidity: Plants will grow better in higher humidity but will survive if everything else is good and the humidity isn’t optimal. There must be good air movement with higher humidity. Light: Slowly adjust the plants to the light they will receive as mature plants. Start them off slightly shadier, moving into more light after 2-4 weeks. The leaves are more sensitive at this early stage.
Note: The Orchid Council of NZ last month published an information sheet about importing plants. Read it here (opens as a pdf).
The trophy presentation more or less closed the Tauranga Orchid Show yesterday. Well done to all the winners, and all those who won placings for their plants. The full set of results is available here. Many thanks to Pam Signal of the BOP Judging Group for preparation of the results.
Judging took place at the Tauranga Orchid Show this morning, keeping the hall buzzing as the various groups deliberated their choices. But finally not only were placing certificates slipped on to plants, but the trophies were decided too.
Not surprisingly Tauranga club member Craig Parsons won large for his huge Dendrobium nobile that comes complete with a section of tree trunk! Craig told the story of this plant in a 2018 post. Read it here.
Champion display: Helen McDonald 1st, Leroy Orchids 2nd, Patricia Hutchins (Sunvale Orchids) 3rd. All small displays and all beautifully presented. Great to see Helen and Patricia (both TOS members) do so well.