I noticed random jujube trees looking a bit ‘not right’ one day in November 2022. And then almost overnight they looked even more ‘not right’ - as in looked like they were outright dying! Pathetic drooping brown leaves covering entire (small) trees with barely, or any, green in sight. For example:
The only thing they had in common was that they were all in roughly 250-350 mm diameter pots. Other than that, they were in different locations, were of different ages, and of different cultivars. Some were pretty old rootstock not potted on in years, while others were one and two year old grafted cultivars all potted in the same medium back in 2021. Some were in regular black nursery pots and some were in 3 L Air-Pot containers. All were always surrounded by similar trees bursting with health and vitality.
I wondered about curl grubs (the larvae of Christmas beetles and the Black African beetle) causing root damage, but wasn’t convinced enough to uproot any trees to look — these larvae feast on grass roots predominantly, jujube trees have pretty thick, tough roots, and for this to be the cause would be a first since forever. I also didn’t want to risk literally killing any tree with a chance of saving by uprooting it during the peak growth season.
I did do a scrape test though - gently scraping away the uppermost bark on the very tips of each tree to see the colour underneath. All had perfectly healthy bright green sap, meaning the entire length of the trunk (and leaves) was being fed.
Water was fine, nutrients were fine, nothing made any sense, so I resigned myself to some losses and left them be. (I was still upset!)
And then I noticed some of my beautiful Japanese maples (Acer palmatum) were doing the exact same thing! I was really getting upset now! Again, these were in pots, all potted on at the same time and in the same medium in winter 2022, and again looking dead almost overnight, in the vicinity of other happy, healthy maples. What on Earth was going on?
Maybe a week later I noticed the tiniest little leaves growing back on the maples — the penny dropped and I checked the jujubes, and sure enough, they too had new growth coming back!
Both Japanese maples and jujubes are deciduous species, and I truly believe that the affected trees had been tricked by this very cool spring and summer we had been having, and had been preparing for dormancy. We didn’t have a genuine summer’s day until Christmas Eve, just high teens and low 20s right through spring on. No doubt our experience is much like Sydney’s to our north, which is officially experiencing a record number of consecutive days below 30 °C (thanks for the link Adrian!).
Anyone into gardens and plants would probably agree the whole of 2022 was a shocker for growing plants, whatever the type. Every one of us probably has a personal sob story! People into propagating especially noticed that things were ‘different’. Light- and/or temperature-dependent seeds not germinating at all. Other seeds germinating late, or germinating in a timely fashion but then not growing much at all. Cuttings with an abysmal strike-rate, dying quickly or just sitting there in suspended animation. More established plants not flowering, flowering poorly, or flowering out of season. On and on.
Nothing has felt normal recently. I’m hearing from seasoned tomato veterans in Sydney and Canberra — two different latitudes, longitudes, altitudes and climates — of healthy tomato plants growing well but with very delayed flower production.
One striking example is my personal experience with the beautiful Kaempferia rotunda, a plant with a most stunning flower and leaf. This species is new to me and a truly wonderful friend (Les) gave me several from his collection to appreciate. Like most in the Zingiberaceae (ginger) family, K. rotunda dies down over winter. But come mid-November the beautiful flowers appear, which only last two or three days. The magnificent leaves appear soon after that. You never, I was told, ever see the flower and leaf at the same time! (Even Wikipedia says this.)
But not this year! Not only were the flowers and leaves appearing together, but the flowers were lasting two weeks in some instances. Les said he has never seen this in twenty years of having them.
Let’s also just say that lawn-mowing is normally a weekly event here in summer, and I have barely seen or heard it in action!
Jujube trees are just one species which is especially sensitive to temperature and requires low nighttime temperatures to induce dormancy. Japanese maples just so happen to be another. Well, when we’ve been wearing winter pyjamas and needing a blanket on the bed into January, you can guess how much colder it was back in November…
Most people do not realise we are currently in a solar minimum, which began in December 2019. (And it is looking to be a grand solar minimum, as Professor Valentina Zharkova explains in her 2018 talk.) Solar cycles last on average eleven years, with sunspot activity and solar flares lowest during a solar minimum.
Back in 2015 Zharkova predicted above-average warmer summers with much colder winters in the northern hemisphere, while in the southern hemisphere summers would be cooler and winters would be warmer. Indeed, 2022 was truly odd, in that we never had much of a winter, and not much of a summer either. Which could explain the unheard of sight of baby Eastern water skinks (Eulamprus quoyii) — in July! And probably why they’re unusually large right now, with several months’ head start!
Another outcome of a solar minimum is increased cloud cover, due to lower solar activity and increased cosmic radiation. (I haven’t been taking notes, but bright blue cloudless sunny days these days do seem more noticeable by their absence.)
‘Cosmic radiation’ is made of high-energy particles such as hydrogen ions (protons) and other atomic nuclei (containing protons), and which originate mostly from outside the solar system. The sun’s magnetic field protects the solar system from bombardment by these particles, but more will ’slip through’ and enter Earth’s atmosphere during a solar minimum, as there is less sunspot, solar flare, and solar wind activity to push them away.
The electric charge of these particles hitting our atmosphere causes clusters of molecules to form. These clusters become ’seeds’, or nucleation sites, around which water molecules condense and form clouds. High cloud cover leads to lower temperatures and light intensity, and affects how light is scattered.
Some plants are sensitive to red and far-red light as a signal that the winter solstice is approaching. The longer wavelengths of red and far-red means these scatter less through clouds than blue and ultraviolet.
It may well be that an unseasonal combination of low temperatures and more exposure to red and far-red had tricked some plants into thinking winter is coming, and to prepare accordingly. Only for a period of normal warm weather and cloudless days to reverse that process and cause leaves to regrow!
Please help me buy a plant if you found this article interesting or useful!
Welcome back! - it’s been a while!
A most interesting, authoritative and demonstatively correct depiction of what happens in nature when plants become confused seasons-wise.
No doubt and over time plants will evolve to climate as it changes - or will perish if they can’t adapt.
Until reading the article I also had difficulties in understanding why side-by-side plants in our garden showed the same symptoms as described here. It’s much clearer now.
Good work and looking forward to the next article.
Thanks! I really hope to get back into a routine here again.
Yes, once it twigged what was going on I see it everywhere now!
This is why it is so important to maintain as much genetic diversity as possible, in everything including animals. And if you’re into home-grown vegies, select for local conditions by collecting seeds from the best-performing ones.
I discovered self-seeded snow peas and broad beans last month - these are winter crops for me and I’ve never seen that before in summer! I was really surprised at just how quickly the snow peas especially grew to maturity - it was “is that a snow pea seedling??” one week to actually picking them a month later instead of a more usual two or three. No joke. So will definitely be letting those go to seed, just in case.
Time will tell if a lot of GMO stuff fails or performs miserably over the years.
Welcome back & thanks for another informative read. I appreciate you sharing the journey, taking me with you with your curious mind 💚. Interesting times hey, with all the environmental changes and disruption to long established patterns of timing, some disturbed by natural anomolies, others by human activities. Keeping our hands in the soil is certainly an adventure that I’m always learning from!
Thanks, Ian Epic Earth (formerly Ian Thomas) (yes, rather excitingly I’ve changed my name to reflect my personal mission to help advocate for this gorgeous planet:)
Thanks Ian Epic Earth! Love to know more about your personal mission if you’d love to share, whether here or privately if you prefer?
Yeah sure kristi, I’m happy to share. I studied an honours degree in Env Sci 20 + years ago and learned then how agriculture and industry are the main culprits when it comes to environmental degradation and disrespect. That industrial agriculture in particular is depleting Earth’s capacity to filter the pollution we’re creating by degrading soil health, poisoning us and yielding crops of a diminishing nutritional profile. And yet it happens away from where most eyes see it, so we ignore it and keep consuming tasteless food thinking it’s nutritious.
My passion is for cultivating foods that are grown in ways that regenerate soil health and contribute to healthy ecosystem function, grown on a small scale, at home, by hand, with mixed species and many flowers to support wildlife. I believe that growing at least some of our own food actively connects us with Earth, reminds us of our custodian relationship, our ‘true’ role on this planet. It’s my personal mission to help more people, discover and remember the joy of living in a reverent relationship with the food they consume, the plants they cultivate and the ecosystems that support them and the beauty they bestow. I believe that if more people grew some or more food, there’d be less need for agriculture and when better nourished, more people can be more resourced to stand up for and protect natural ecosystems that commercial interests are seeking to commodify and pillage.
I live this mission by sharing my passion and skills for growing more food, of better quality, for less work through my organisation The Gourmet Garden School 🥕
In all honestly learning how to grow food plants better is my biggest love and it borders an obsession, albeit a ‘healthy’ one😂
That’s a brilliant philosophy, and thanks for sharing Ian!
Yes, a lot of people discover just how fulfilling life is once they take on more of the custodian relationships you refer to.
May I ask what your major(s) and honours project were?
Yes by all means. My honours dissertation was on tomato plants and their individual response to heterogeneous v.s. homogenous distribution of nutrients in their soil. It was fascinating to see the variability in performance according to different distributions of compost (the nutrient-rich media) and sand. In truth I forget what my majors were, it’s been a while 😅
Anyway it was the start for me with my love of understanding plant and soil health, and the intricate interrelationships there. I followed a proverbial rabbit down a hole and I’ve never come out!
I must say I’m very appreciative of your clear grasp and eloquence for explaining plant physiological responses to external stimuli and the way you explain the way plants function. I’ve really enjoyed reading your posts! 😊
Please, you’re going to have to tell me more :)
Would you mind at all elaborating on the details, as I’m not quite clear as to the setup sorry? Heterogeneous was compost in sand, or…?? And homogeneous was pure sand, fertilised somehow, or…?
Many thanks for the warm fuzzies :) Good to know the posts are of interest!
Trust you to take interest in the details! From what I know of you through your words, I’m not surprised! Here’s a few pics that’ll explain the project much easier, there’s obviously lots missing, but this’ll give you the gist! I ran an experiment first to determine how many replicates i’d need to achieve statistically significant results, 10 was the answer. Then trialled a range of different ways to explore plant growth response to various spatial distributions of media. I also tested a liquid fertiliser with a single application point. See attached images 😊
And, I’d love to take this offline, drop me an email:) email@example.com
<laugh> Sorry, can’t help it!! Awesome, many thanks - am currently writing a new post so when that’s up I’ll definitely be looking at these and shall drop a line sometime in the next few days :)