At this point, I’m thinking this series of posts should perhaps be “Botany Word of Whenever I Get Around to It.” Sigh …
Anyway, this is a fun one! Thigmotropism is a plant’s growth response to touch. If you have a vining plant with tendrils, you may have watched, fascinated, as the tendrils wrap around a support. Epidermal cells in the tendril (which, in some plants, can be ten times as sensitive to touch as human skin!) cause it to reach and latch on when it contacts a solid object.
The tendrils use differential growth to wrap themselves around objects such as another plant, trellis, or wall. The side of the tendril that is opposite to the side that is in contact with the object grows faster due to the production of the growth hormone auxin by the side that is closest to the object. This causes the side that is touching the object to compress at the same time the other side elongates. The tendril then curves towards the object in a positive response.
Typically, thigmotropism is a fairly slow response, but in some plants, it occurs quickly. This is called rapid contact coiling, which occurs due to turgor pressure. (Turgor pressure is the pressure exerted by water that pushes plant cell membranes against cell walls. It maintains the rigidity of the cell walls and helps support the plant.)
Roots also exhibit thigmotropism (in addition to gravitropism, which is a term for another day, perhaps!). Unlike tendrils, however, roots react in a negative way to encountering a solid object such as a stone in the soil – that is, they move away from it, rather than towards it. This makes sense, as roots want unencumbered access through the soil, to facilitate the uptake of nutrients and water.
And, on a side note, you may be thinking that sensitive plants (Mimosa pudica) also display thigmotropism, but their response to touch is actually non-directional; that is, they don’t move towards or away from a stimulus. Instead, they experience what is called a nastic movement.
Why is thigmotropism important? It allows some climbing plants the opportunity to reach for more sunlight … which means more efficient photosynthesis can occur.
Welcome to the fourth issue of The Guides for the Prairie Gardener Newsletter! Janet Melrose and I are keeping you up-to-date on everything related to our book series Guides for the Prairie Gardener, letting you know about what other Prairie gardening-related projects we’re working on, and throwing in some gardening trivia and newsy tidbits, just for fun! If you like what you see, please follow us on our social media and hit the subscribe button on Flowery Prose.
Book News and Events
Request for book reviews!
Do you have a copy of either of (or both of!) our books, The Prairie Gardener’s Go-To for Vegetables and The Prairie Gardener’s Go-To for Pests and Diseases? If you do, can you please help us out and take a couple of minutes to give us a rating and review on Amazon.ca/Amazon.com? Don’t worry about leaving a lengthy review…two or three words is honestly all Amazon requires. If you’re on GoodReads, leaving a rating over there would be wonderful, as well! Thank you so much! We are so grateful for your support and encouragement and we hope you are finding the books informative, useful, and fun!
We’ve been on a podcast!
Janet and I had the pleasure and honour of being guests on Agriculture for Life’s Know Your Food podcast, for not one, but TWO episodes! We talked about growing veggies and other edibles, encouraging children to catch the gardening bug, and the connection between the coronavirus pandemic, self-sustainability, and growing your own food…and a few other topics, besides! Go to Ag for Life’s website to listen.
Congratulations to Sherryl H. and Linda H., who each won a set of The Prairie Gardener’s Go-To for Vegetables and The Prairie Gardener’s Go-To for Pests and Diseases by participating in a contest run here on the blog earlier this month. A huge thank you to our publisher, TouchWood Editions, for supporting the contest and providing the prizes for the winners!
Out and About
Sheryl:
After being laid off for nearly four months, I am back to work at the library and, combined with my writing schedule and gardening and the need to eke out a few fun summer activities while there is still time, I’m a wee bit swamped. I have an ever-accumulating load of articles to write, questions to answer for curious (and occasionally desperate and fed up) gardeners, thunderstorms to dodge (my tomatoes have spent half of their lives covered up with sheets to prevent hailstones from destroying them), and So. Much. Weeding. The weed du jour (besides quackgrass, which is actually the bane of my existence): stinkweed (Thlapsi arvense). At least stinkweed is an annual, and it spreads via seeds instead of rhizomes (or seeds AND rhizomes – shudder). It’s easy to pull but there seems to be an incredible amount of it this year. Stinkweed has the glorious distinction that if it is allowed to set seed, one plant can produce 15,000 seeds. I’m pretty sure all of those germinated in my raised beds this year, alongside a zillion annual chickweed plants (Stellaria media), which are another story altogether.
A few articles that I wrote earlier in the year have made it to publication – check out “Harvesting Rain’’ in the Summer 2020 issue of The Gardener for Canadian Climates and “Superb Serviceberries” in Mother Earth Gardener. Both of these are available on newsstands across Canada – and in the case of Mother Earth Gardener, you can find it anywhere in the United States, as well. (You can also read the article online here!). I also went a little farther afield than usual and wrote an article called “Opossums as Pollinators in Brazil” for the April 2020 issue of 2 Million Blossoms. As you can imagine, that one was fascinating to research! This is a beautifully-produced, brand-new publication out of Arizona, dedicated to celebrating and “protecting our pollinators.” (If interested, you can order a subscription from their website).
I also had a chance to do a story about houseplants, for a change – my article “Devil’s Ivy vs. Philodendron: Which is Which?” can be found online at Farmers’ Almanac. Check it out here! And, finally, “Using Colour in the Garden” was published in the July 4, 2020 issue of the newspaper The Calgary Herald. You can read it here.
Janet:
Unlike Sheryl I have been taking a hiatus from writing and workshops since the middle of June, although my article ‘Attracting Butterflies with Annuals’ is in the Summer issue of The Gardener for Canadian Climates. It was a joy to research, write and photograph and I hope any of you that take in this magazine enjoys it too.
My Horticultural Therapy programs are all in abeyance too, except for one that is online!
So, my days have been filled with planting, sowing and weeding all the gardens that folks in the programs usually do. Plus, every so often, getting into my own garden.
One thing I haven’t had to much at all is watering, seeing as the sky has repeatedly provided ample moisture. Apparently, Alberta is experiencing La Nina like conditions in the atmosphere which have been contributing to our cooler and wetter weather lately. There is also a 50/50 chance of a full blown La Nina for this winter. Can we say cold and snowy?
I have been loving the chance to get out into the wild where the wildflowers have been stunning along with the insects and birds. Usually my days are filled in the summer months and I seldom get the chance to go out and about. If there is a silver lining to this year, it is the joy we Albertans are getting from relearning our own backyards and wild spaces!
Mountain bluebell – Jasper, Alberta (photo by Janet Melrose)Western lily – Jasper, Alberta (photo by Janet Melrose)Lady’s slipper orchid – Jasper, Alberta (photo by Janet Melrose)
In Our Gardens
Sheryl:
As I already mentioned, weeds are what’s happening. We have had a lot of rain and now there are weeds everywhere. I’m a bit weird in that I don’t mind weeding: I like to relax in the sun and pull and dig them up by hand. Weeding is just a really nice opportunity to turn the ol’ brain off and listen to the birds sing and the bees buzz in the garden. More importantly, it’s a way to get really up close with your plants and see what’s going on almost at soil level. Sometimes you get in a rush and you run to the garden to grab a handful of lettuce for a supper salad, or you sprinkle some water over everything before you dash out to work in the morning and you don’t really SEE what’s going on out there. You need to sit and go slow to do that. If you take a look at our pests and diseases book, you’ll notice that we talk about Integrated Pest (Plant) Management. One of the tenets of that practice is monitoring. That’s one of the things you can be doing while you weed: monitor your cultivated crops and ensure they are healthy and stress-free. If they aren’t, maybe you can see what the problem is while you’re out there weeding.
In July and August, everything is up in the garden and you’re just taking it all in, harvesting a few crops here and there and waiting on others to get larger or to produce more. We’ve been enjoying spinach, lettuce, Swiss chard, scallions, garlic scapes, kohlrabi, and various herbs – and, of course, potatoes (which are honestly the real reason I grow vegetables, LOL). And now the beans are coming along as well and the zucchini (which is seriously late for me this year).
A bit of hail damage isn’t stopping those nasturtiums and calendula! I always mix edible flowers into my veggie beds. (Photo by Sheryl Normandeau)
Janet:
I have been having so much fun working in my bed at Inglewood Community Garden. It is a 10’ x 4’ bed so I have taken our Victory Garden plan (which you can see here) and used it in this bed using the square foot gardening technique to control my urge to just add a bit more into it.
Bumper harvest – Inglewood Community Garden (photo by Janet Melrose)
It is producing magnificently with my four kale plants in full production, along with lettuce and chard galore. This year with all the rain our radishes were wonderful….mild tasting, beautiful round orbs and nary a radish maggot to be found. Soon it will be the turn of the pole beans, garlic and tomatoes as they all come into their own. And I grew the best cilantro I have ever done, with it tucked in the shadow of the tomatoes and under floating row cover the entire time. A testimony to the benefits of using this ‘gardeners’ best friend’, not to mention the value it provides as hail protection!
Best cilantro ever! (Photo by Janet Melrose)
As I love to get as much as I can from a space I have already sown more radishes where the cilantro was in the hopes that the conditions there will good enough to get a second delicious crop. While the first lettuces are being harvested using ‘crop and come again’ I have sown more seed to germinate while I munch through the first round of delicious leaves. When the garlic come out in a few weeks I have more seedlings growing in wintersowing jugs to take that space to continue the bounty!
Fantastic radishes! (Photo by Janet Melrose)
FloralMiscellany
Sheryl:
A couple of the questions that keep cropping up (pun intended) on the Alberta Gardening group on Facebook concern the topic of growing onions. If you’re waiting on your onion bulbs to plump up and you know it’s going to be a few more weeks, what do you do if flowers suddenly show up? Do you cut them off? Do you leave them? And some gardeners stomp down the tops of their onions at this point in the growing season because they think it will promote fatter bulbs – is that something that should be done? (I’ve seen people recommend this for potatoes, as well). Let’s get down to the bottom of this!
Janet:
Continuing on with the Allium family, garlic (Allium sativum) is taking centre stage now. Our late and cool start to the growing season has meant that they are only now developing the distinctive curl to the scapes, but now is the time to snip those scapes back to the first set of leaves. A gourmet delight and expensive in stores, use them just as you would the cloves for your summer cuisine. They pickle and pesto perfectly too if you have too many to use fresh!
Then watch for the leaves to turn yellow and die back in the next few weeks. Once they are about one third brown harvest one to see if the bulb is big and well formed. If it is, then harvest the lot as left too long after that the quality starts to degrade. Cure for three weeks in a dry and warm spot and we have fantastic garlic for the winter months plus using the best bulbs our stock for planting come fall when the cycle begins again!
If you love growing garlic like I do check out Ron L. Engleland’s iconic book ‘Growing Great Garlic’.
A few weeks ago, I received a question from a gardener in the city who wanted to know about the best hydrangeas to grow in Calgary. Due to our climate, we’re not able to overwinter the really showstopping bigleaf types (H. macrophylla) that gardeners in warmer regions can, but we still have some extremely nice selections to choose from. I suggested that, due to sufficient cold hardiness, smooth hydrangeas (H. arborescens) and panicle hydrangeas (H. paniculata) tend to fare best in our part of the world – and then he wanted to know: what on earth did I mean by the word ”panicle”?
Good question! The term panicle is often associated with grasses. Most grass panicles are easy to identify. Here is an example: Take a look at the fuzzy top of foxtail barley (Hordeum jubatum, a beautiful but persistent, troublesome weed here in Alberta). That lovely plume is a panicle, a type of compound flower head that features long, sliver-like awns, which can cause pain for livestock that accidentally graze on the plant.
With hydrangeas, what we think of as one huge flower is actually a panicle. Like the fuzzy flower head of foxtail barley, a hydrangea’s panicle is a compound inflorescence. It is made up of tiny individual florets, which are attached via pedicels (stem-like structures) to “branches” called racemes. Panicle hydrangeas are named for this type of floral arrangement.
Do you grow hydrangeas (any types)? If so, which ones are your favourites? (If you have any, please feel free to link up to photos of your hydrangeas on your blog or website – I’d love to see them!).
Particularly at this time of year, when the new candles are formed, mugo pines may appear to be the angriest shrub of the plant world, looking for all the world like they are furiously gesturing to the idiot that cut them off in traffic. (Now you’ll never see them the same way again. You’re welcome). 😉
Mugos have shorter needles than most pines, but they’re still fairly long (up to two inches), elegant as befitting pine trees, and clustered in pairs. If you touch the needles, they’re not particularly soft like some other pines. Again, that sort of fits with the whole angry thing.
On the larger cultivars, the branches are supposed to sweep upwards in stiff arcs, but the shrubs themselves sometimes acquire a sprawling habit as they age (I completely understand this as I have, too), so this isn’t always accomplished as well as it should be. When left unkempt, unattractive bare spots often open up in the centre of the shrub. (You can – carefully and judiciously – prune the shrubs every few years to maintain a more tidy, compact shape). Smaller cultivars, such as the lovely ‘Mops’ (which really does look like a ploofy green mop turned upside down and stuffed into the ground), tend to be a tad more well-behaved.
Once you’ve got the ID down pat on these, you’ll start to realize how common they are, at least in urban areas here on the prairies. Their hardiness and compact size (small and smaller) make them tough to beat as landscape specimens. They’re pretty much a go-to for residential and commercial foundation plantings. Although it does occur in particularly harsh years, mugos tend to resist winter desiccation a bit better than many other conifers, and that’s a big deal around here.
What are your favourite conifers (small or large) in the garden? (It doesn’t matter where you live, I’d love to hear about them! They don’t have to be suitable for the Canadian prairies).
It appears that my intentions and reality do not mesh, yet again…a Botany Word of the Week is just simply too much for me to maintain on top of all my other projects. But I love creating these posts and I hope you enjoy reading them – so I’ll switch to a monthly format which should be far easier for me to complete. We’ll see…intentions, you know….
Dehiscent
If you have a medical background, you’ll already know what this term means…except I’m going to use it in relationship to fruits.
When they are mature and dry enough, dry dehiscent fruit split open to release their seeds. Dehiscence is this act of breaking open at a seam. The part that splits is the pericarp (comprised of ovule-bearing structures of the flower called carpels).
The dry dehiscent fruit you are probably most familiar with belong to legumes. Peas, beans, and lentils fall into this category. They all have one carpel and if you’ve ever shelled garden peas, you’ll recognize the way that carpel splits open (except that you’re facilitating the split before it’s “supposed” to happen. When you allow peas to dry for harvesting, and they split open, then you’re letting them do their thing).
Do you remember this post I did a couple of years ago about the ‘Le Puy’ lentils I grew? What I’m describing there is the explosive way the dehiscent fruit burst open when they’re ready. And I’ll never forget the way that the seed pods of the Caragana shrubs that lined the driveway to my childhood home audibly crackled and violently burst on hot, late summer days, showering the seeds everywhere.
‘Le Puy’ lentils…not yet dry enough to split open.
Peanuts are one dehiscent legume that don’t – thankfully – burst open when dry. You have to help them along by breaking them open yourself.
There are always exceptions. Some legumes have indehiscent fruit, and their carpel does not split open when dry. If you have a honey locust growing in your yard, that’s a good example.
Legumes aren’t the only dry dehiscent fruit. There are capsules, which have more than one ovule. Lilies and poppies have capsules. There are also follicles, of which plants such as columbines have more than one. Siliques are another. These are a type of elongated fruit that kind of resemble legumes. If you’ve ever allowed your radishes to set seed, that pod you’re looking at is a silique. Just for fun, there are also silicles, which are not as long as siliques. Honestly, I’m not making this up, even if it sounds a bit giggle-inducing.
What is your favourite dry dehiscent fruit to grow?
Aggregate fruit (as well as some bonus chatter about accessory and multiple fruits, pseudocarps, drupes, achenes, carpels, and…um…monkey bread?)
Occasionally (or possibly frequently, given the weird world we live in), things turn out to be different than advertised. Sort of like that purse I ordered off of the Internet. But I digress….
Case in point: raspberries and strawberries. Are they actually berries? You already know where I’m going with this!
What does it mean to be a berry? Quite a few things, really, but one of them is that the fruit must develop from a flower possessing one ovary. Strawberries and raspberries don’t fit the bill. If you take a look at the fruit of a raspberry, you’ll notice that it is made up of a bunch of little nubs. You could pull each one apart, kind of like a loaf of monkey bread. (Mmmm…how can you tell I haven’t eaten breakfast yet?). Each one of these is called a drupe (drupelets), and they are produced from the multiple ovaries of a flower. Each drupe contains a seed. In the case of a strawberry, those little seed-like things on the outside are not actually seeds, although they do contain seeds. Those small bumps are called achenes. Because these fruitlets were all joined together, they are called aggregrate fruits. (Just to be confusing, not all multiple fruits – those with more than one ovary per flower – are aggregate. Some don’t join together to form a single entity).
And, to add to the fun, strawberries are categorized as an accessory fruit (aka pseudocarp) in addition to an aggregate fruit. Some of that yummy fleshy stuff we eat is made up of tissue that originates near the carpel (modified leaves that surround the ovules) of the flower.
Okay, now that we’ve got that out of the way…I’m off to enjoy an aggregate fruit smoothie! (Doesn’t have quite the same ring to it, does it?). Do you grow raspberries and/or strawberries in your garden? What ways do you use them in cooking and baking?
A plant that bears a pappus (or more likely, pappi) is said to be pappose. With purpose. And no porpoises. (Please stop me before I go any further).
What’s a pappus, you say?
See this dandelion flower (actually a cluster of florets) that has gone to seed? If you’ve ever held one in your hand and pulled a single seed away from the head, and then eyeballed it really closely…you’ll see that the fine, fuzzy white stuff on top (actually a modified calyx) sits above the thin brown seed like a skeletonized parachute. The parachute calyx is a pappus, and although you can’t see all of them really well without a microscope, if you could count, you’d find that there are around 100 bristle-like filaments comprising each one. As dandelion seed is dispersed via wind, this pappus structure proves very useful, able to carry the seeds up to 100 kilometres (62 miles).
Dandelions aren’t the only plants that are pappose – you’ll find that most members of the daisy (Asteraceae) family are as well – but I’ve got one more fascinating dandelion pappus story to share before I sign off on this post. Get this: In 2018, researchers at the University of Edinburgh (using some cool gadgets such as a wind tunnel, lasers, high speed cameras, and x-ray microtomography) discovered the precise number of and the specific way the filaments in each pappus are arrayed makes even more of a difference to the efficiency of wind dispersal of the seeds than previously thought. It was an accepted theory that the resistance (drag) of individual filaments to wind makes dandelion seed so good at flying. It turns out that the way that moving air flows around each individual filament – and the filaments around it – creates a sort of stabilized vortex ring, allowing the seeds to stay buoyant for an impressive time and over long distances. You can read all about the physics of this amazing adaptation here.
I quite often set up theme days in the Alberta Gardening Facebook group I administer (especially during the winter, when we’re all suffering from cabin fever!). This morning, for some Valentine’s Day fun, I requested that everyone list their favourite red, pink, and white garden flowers/veggies/fruit. I thought I’d do it here, too, and compare answers. So far, they’ve posted amazing photos of petunias, daylilies, tomatoes, onions, raspberries, roses, poppies, tigridia, dahlias, peonies, and painted daisies…and they’re still at it.
I’ll start us off. Next to sweet peas, roses are my very favourite flower, and I’m especially fond of the hardy roses that withstand our crazy cold climate and look pretty marvelous doing it. The Explorer series is one example…and you have to admit these rich red double flowers of the beautiful shrub rose ‘Champlain’ are quite stunning. (If you’re ever in the small town of Pincher Creek, in southern Alberta, you’ll see this rose featured in the Lebel Mansion rose garden, maintained by the Oldman River Rose Society).
What are your favourite red, pink, and white garden flowers (or vegetables or fruit)? Please feel free to link up to photos on your blog, Instagram, whatever – show us the plants that you love! ♥
