Interesting Plants – Page 15 – The Garden Professors™

Surviving the desert with beauty and efficiency

I’m away this week for an out-of-state seminar and a little annual leave. Some of my favorite places to visit this time of year are the high deserts of California. Today we hiked to Horse Thief Creek, a relatively easy trail in the Santa Rosa Wilderness. It’s the perfect time of year to see the high desert in bloom, especially with last winter’s substantial rainfall.

In graduate school I became interested in environmental stress physiology, and I still am entranced by the plant kingdom’s ability to overcome nearly every environmental extreme on earth. Desert ecosystems are particularly harsh, as rainfall is limited to a short period of time, often in the winter or spring. While many perennials are able to tolerate the subsequent dry season, annual species cannot. In essence, they escape drought stress altogether by existing only in seed form for most of the year. Seeds contain relatively little water anyway, and are so protected against environmental extremes that they can remain viable for decades or even centuries.

But back to our desert. After the rainy season, seeds of annual plants go into overdrive, germinating, growing, setting seed, and dying back all the span of a few weeks. Thus, the lucky hiker can find an abundance of tiny, brilliant desert annuals when seasons and vacation schedules coincide.

Tomorrow it’s the Salton Sea. Not sure what we’ll see in terms of plant life, but we’re hoping to catch some of the migratory waterfowl on their journey north.

Devious dandelions

As Austrian reader Johannes explained, the difference in dandelion flower height is due to herbivory – in this case from a lawnmower. Dandelions are quite adaptable to variable environments (the phenotypic plasticity Johannes also mentioned) and flower heights will increase or decrease depending on these variables. This ensures that the flowers will be accessible to pollinators, yet not decapitated by lawnmowers. It’s just one of the fascinating traits that make weeds successful!

A Taraxacum teaser

It’s spring and the dandelions are happy to see you! I’ve taken photos of two groups of dandelions just footsteps away from one another. The populations are both in full sun, with similar types of soil and water availability. You’ll note that one group has very short flower stalks, while the second has longer stalks:

So what’s responsible for the difference in flower stalk length? And for extra credit, what’s the scientific term for the phenomenon?

If this isn’t something you’ve noticed before, you will from now on! Answers Monday!

Edgeworthia!

Some of my favorite plants are those that “do something” when little else is.
Do we really need more June-flowering perennials? No!
Well, yes. Never mind.

Edgeworthia chrysantha – “Paperbush” is the common name – is a deciduous suckering shrub , native to China. It usually maxes out around 4′ to 5′ tall and as wide. The large, matte bluish-green leaves resemble those of Magnolia virginia in shape and are also a bit silvery on the underside. But that’s not what we’re here for…

An oooh-aaahhh-worthy specimen at the Hahn Horticulture Garden, Blacksburg, VA.

Furry, silvery flower clusters dangle like earrings from the cinnamon stems throughout the winter, getting larger by the month.

Then by late February or March, they open up, all golden and waxy, emitting a light, sweet fragrance on sun-warmed days.

Blooms at Pine Knot a few Springs ago…

Edgeworthia is ideal for the deciduous woodland environment. Hellebore specialists Dick and Judith Tyler of Pine Knot Farms (Clarksville, Virginia), situate theirs among drifts of spring bulbs and, of course, Hellebores. It’s a soul-stirring sight in March.

I believe the hardiness of Edgeworthia may be underestimated, especially if you go to a little effort to select the right microclimate. Dr. Dirr lists it as Zone 7 to 8(9). Having enjoyed them at the JC Raulston Arboretum during my doctoral work at NC State (Raleigh, North Carolina; Zone 7b), I found Edgeworthia was little-know here in the Blue Ridge (solid Zone 6, alledgedly 6a). We ordered some in for our Garden and Hort Club’s 2007 plant sale held in late April – despite my pleading and mark-downs, they didn’t generate much interest from shoppers as they were out of flower. We planted the left-overs in a fairly protected position on the North side of our garden pavilion, and they’re thriving. Snow was heaped up around them throughout January and February and we’ve gotten well into the single digits complete with howling winds a few times. Despite this rotten winter, they look better than ever, ready to burst into bloom any day now. Readers, please weigh in: Had any success with it in Zone 6? And why isn’t this fabulous thing more prevalent in the trade?

I’m Saving Myself for Pollination

Let’s take a very brief respite from the socio-religious implications of science, soil testing, and compost tea to ponder a more lighthearted topic. I need a bit of a morale-boost.

You: “O.K. Holly, Spring’s allegedly coming…how about a closer look at some wildflowers?”

Me: “Done!” (fingers snapping)

For a short time in March, forest floors across Eastern North America can be absolutely littered with a multitude of sparkling white flowers. This very cool little plant, Sanguinaria canadensis, is one of the first wildflowers to emerge in the spring and colonizes deciduous and mixed woodlands.

Flock of bloodroots, open for business at the fabulous Mt. Cuba Center.

A member of the Poppy family, Sanguinaria is a monotypic genus; that is, there’s only one species. Commonly known as Bloodroot – mostly. However, S. canadensis is also known as (and I quote): Bloodroot, Red Puccoon, King Root, Red Root, Red Indian Paint, Ochoon, Coonroot, Cornroot, Panson, Pauson, Snakebite, Sweet Slumber, Tetterwort. Large Leaved Sandwort, Large Leaved Bloodwort, plus whatever else Aunt Minnie “knowed it by”.

As one of the first wildflowers out of the ground, it’s still darn cold when the Bloodroot flower appears, and they’re quite protective of their private parts. The one leaf emerges at the same time and cups around the flower, helping to protect the fragile blossom from wind, rain, and snow. The petals also close up at night to save the pollen,since in most locations it’s so cold that few insects, save the occasional fly or beetle, are out and about. And as a last resort, they can just “do it themselves”, better described as self-pollination.

I have been pollinated! Victory is mine!

If you break off a stem or piece of the root, out will ooze a reddish-orange juice, hence the common name. It’s been prescribed for myriad conditions by Native Americans and herbal practitioners. One of the more interesting properties is that the sap is an escharotic – it kills tissue. Ironically, according to herbal lore, to draw love to you, wear or carry a piece of the rhizome. If attempting this bit of magic, maybe it’s best not carried in one’s pants pocket.

My summer vacation

I’m following Holly’s lead and slipping into fantasyland today. Though this part of the country has no snow, it is a typical cool, misty and gray winter morning in Seattle. So I’m going to a happy place and reminiscing about my summer vacation to Sechelt, British Columbia.

Sechelt (pronounced like “seashell” with a “t” at the end) is a lovely place full of wonderful people (and great gardeners!), but I’m going to focus on the coastal rock gardens at Smuggler’s Cove Marine Provincial Park. We visited on a day much like the one I’m experiencing now, so there weren’t many visitors. All the better for us.

Since my interests trend towards plant adaptations to harsh environments, this rocky, salt-sprayed landscape naturally drew my eye. Trees colonize the bare rock, rooting along cracks and fractures.

Even though we were past the flowering season, these natural gardens were still striking with their miniature plants. Many of these are cushion formers, and together they formed living patchworks.

And there were still a few wildflowers left as well.

Hot and dry in the summer, constantly sprayed with salt, and living on the thinnest of soils, these rock gardens nevertheless have a rich diversity of plant and insect life. And all without vitamin B-1, compost tea, Epsom salts, or any of the other products aggressively marketed to the gardening world…truly amazing.

The Glories of The Winter Greenhouse

I’m a Southerner. With a capital “S”. Which is why I am Suffering, with another capital “S”. Here in the Blue Ridge mountains of western Virginia, we have officially surpassed Anchorage and Denver in total snowfall for the season. Today’s batch adds up to 24″ on the ground at our farm.

Blueberries in the snow. If one more person says “Probably good for all the insect problems,” I’m going to get violent.

The chickens are not happy. They’ve been cooped up (ha! I didn’t really mean to do that!) for 10 days straight. I myself suffer from cabin fever, limp hair, seasonal depression, and a persistent cough.

Hell no, we won’t go!

What keeps me from going totally nuts? Only the best $12,000 ever spent – no,no, not granite counter tops…it’s our very own greenhouse. This modest 24′ x 48′ polycarbonate sheet hoop house may not resemble a Victorian conservatory (you can get one of those beauties here), but it works like a champ. Yes, we have greenhouses on campus for research and teaching, but that’s work; and pet plants are frowned upon.

Nothing beats your own private winter hideaway. My plant-diva-friend Elissa uses her crowded greenhouse for not only her immense plant collection, but also a festive (if cramped) happy hour.

As sleet pelts the roof, I’m surrounded by green: tropical plants dug up from the garden before frost and those “pets in pots” accumulated from hither and yon. The humidity is wonderful – I can hear my skin go “aaahhhh” after a couple of hours.

Herd o’ Agaves and succulents. They’re perfectly happy with the cool temperatures – several are blooming.

I’ve dreamed of one for years; then finally took the jump 16 months ago. Again, it’s nothing a homeowner’s association would ever approve of; just a commercial-grade, heavy duty, Quonset-type production house. Stylistic concerns were sacrificed for square footage. The most common complaint from home greenhouse owners is “I wish I had built a bigger one.”

The other concern is heating costs. It has a propane heater, and propane’s not cheap, nor environmentally friendly. But we run it pretty darn cold – around 48 F night temperatures, which certainly helps. Are the tropicals thrilled? Not really, but they’re alive and hanging in there (however, the begonias are really grumpy right now).

Some PVC pipe + overhead misting + heating mat = broccoli spinach, and basil seedlings, happily germinating at a 75 F soil temperature, despite an air temperature below 50 F. Basil?! Yes, I realize I’m totally jumping the gun timing-wise here, made worse by the fact that I teach both greenhouse management and ornamental plant production (do as I say, not as I do!).

Yep, more fun than you can shake a shovel at!
I’ll take your questions, comments, and snowballs now…

Plant Patents

I love patents. In fact, I once wrote a novel based on a patent — It was called Patent 22 — If you look this patent up you’ll just find a piece of paper from 1915 which says, essentially, that a search was made for the patent but that it couldn’t be found. No one wanted to publish it — and reading it now I do realize that it does need some serious work. Still, I think this little tidbit gives you a little bit of an idea about my interest in patents. (The paper on file at the patent office is below):

Anyway, here’s the thing that people don’t know. There are three ways to protect a plant from someone else “stealing” it: Plant Patents, The Plant Variety Protection Act, or a Utility Patent (which is what you or I usually think of when we think of a patent). The Plant Patent Act passed in 1931 and it is the way that most plants are protected today. Plants like the Honeycrisp apple which are propagated vegetatively (using cuttings or grafting) are usually protected with this type of patent. The second type of protection is the Plant Variety Protection Act of 1970. This Act lets you protect seed propagated plants. With these two types of protection you wouldn’t think that any other type would be needed — but the Supreme Court has twice ruled that plants can be protected using Utility patents (once in the 1980s and once in the early 2000s). So, what is the problem with that? Well, basically, the problem with that is that, while the other ways to protect plants allow for the use of those plants in research or for breeding and farming, using a utility patent prevents anyone from using the patented plant from doing anything with that plant without permission from the patent holder. And, basically, an entire species of plant can be patented — it has been done before with a bean that someone brought from Mexico into the US — he cornered the market on the bean and noone could sell or breed the bean without his OK. Sounds insane doesn’t it? Just my first thought on a cold Thursday morning.

All Right, Linda; I’ll See Your Paraheliotropism and Raise You a Nyctinasty

Amicia zygomeris is a cute little herbaceous thing I picked up on a visit to Plant Delights nursery back in October. For $13, I wanted to be sure it survived the winter, so it’s been in our kitchen garden window, just waiting for spring.

Soon after putting it in the window, I had an “oh no, I’ve killed it” moment one evening. All the leaves were drooping, yet the soil was moist. The next morning, it seemed to be back to normal. The following night, droop city again.

Ah HA! Nyctinasty* at its finest – plant movements to the circadian rhythm. Tropisms are growth responses, while nastic movements are just that – reversible movements. There are other “nasties” out there – photonasty is movement in response to light, hydronasty – water, etc. The classic example is Mimosa pudica – sensitive plant – the little leaves fold to the touch (thigmonasty).

Legumes are particularly prone to this – check out the bean plant flapping its leaves in time-lapse video at the “Plants in Motion” website (U. of Indiana Biology Department). The movement comes from changes in turgor of the cells that attach the leaf petiole to the stem. This spot’s called the pulvinus – think of it as the leaf’s armpit. What do plants gain from this daily spreading then folding of leaves? Folks have been pondering this for centuries. Darwin wrote about it in “The Power of Movement in Plants” (1880). Though the biochemical mechanism has been discovered, I don’t believe any conclusions have been reached as to "why".

Amicia zygomeris in the evening. The common name, courtesy of Tony Avent, is “Gotta Pea". I am not making that up.

*BTW, Nyctinasty is also the name of a pop band from Manila. Must be a biologist or two in the bunch.

Friday puzzle answer(s)

Wow! What a lot of great brainstorming over the weekend! I would venture to say that The Garden Professors have the smartest students in the world.

On to the answer…or answers. First, the phenomenon. It’s called paraheliotropism – literally, a movement to protect (the leaves) from the sun (yes, Trena, it is a tropism!). This is the opposite of another phenomenon called heliotropism, or solar tracking. Sunflowers famously do this, as do a number of arctic species that collect solar warmth for the benefit of their pollinators. (An aside: if you have never watched David Attenborough’s The Private Life of Plants you must add it to your Netflix queue. Right now.)

But our saxifrage (thanks, Holly! I’m such a taxonomy imbecile) is reducing solar exposure by positioning its leaves in parallel to the sun’s rays. This is a reversible movement and helps reduce photooxidative stress, leaf temperature, and water loss. It’s an important strategy as the newly emerging leaves are actively expanding. If turgor is reduced by high temperature or water loss, so is the final size of the leaf.

Finally, these rapidly expanding leaves have relatively thin cuticles (if they were thicker the leaves wouldn’t be able to expand as well). The cuticle gives further protection to the leaf from water loss due to heat, drought, wind, or even late season freezing events (thanks for that addition, John!). The cuticle will mature after the leaf has reached its full size.

So, as Foy suggested, this is a way for leaves to "harden off" and reach full size before exposing themselves to the sun. Aren’t plants cool?

And you are all such great participants! Group hug! Now, back to work.