Biochar: Miracle or Gimmick?


Cornell University illustration showing biochar as a means of sequestering greenhouse gases.

I’m always skeptical of what I call the “notions and potions” school of gardening. Every few years there is some new substance touted as the secret to a lush vegetable garden. One such substance is biochar, a kind of charcoal used as a soil amendment.

The University of Minnesota Extension service is in the midst of a four year study to test the use of biochar in vegetable gardens.

Preliminary results (which you can read here) show benefit for some crops such as kale, but a decrease in growth for others such as asparagus.

The more we learn about biochar, the more we need to learn. From an overall standpoint, there appeared to be some benefit of using biochar in the nutrient-depleted sandy soils at the Andover site for some crops. Yet, there was a decrease in growth in some plants and higher yield in others. In the Arboretum and St. Paul campus sites, we noted similar results, but more crops seemed to decline with biochar than without it.

There’s nothing new about biochar. It was in use by native peoples in the Amazon region before Columbus. Hopefully this study will help clarify what types of soils and what crops benefit most from its use.

Do you have an opinion about Biochar? Leave a comment . . .

And thanks to Michael Tortorello for sending me the link.

White Sage and Bees and our other sage friends

bee in sage

One of my favorite plants in the garden (I’ve posted about it before) is in bloom right now: the white sage, Salvia apianaSalvia apiana means “bee sage” and boy howdy did they get that one right. This sage puts up tall spikes covered with small white flowers that bees can’t resist. Unfortunately, our white sage is situated right by the garden path. So these days, every time I go into the garden I have to squeeze past the leaning spires, praying I won’t be stung, because the plant is thick with bees. Covered. It hums.

Now, these workers are so busy that they don’t have time to be aggressive. For instance, they let me stand around taking blurry pictures of them working, until I got the one above. But stings happen by unfortunate mischance in crowded conditions. I suppose I could cut back the spikes, but whom am I to interrupt this passionate sage & bee love affair?

Besides, it’s really pretty. The spikes are about six feet high, but delicate, like fairy lances.

white sage spires

Here is a pic of the white sage as seen from our back door. I decided to leave in the wheelbarrow and some buckets of who knows what, and The Germinator ™ for scale.  Right now this salvia is the star of the garden.

white sage off our patio

All the sages are blooming now, actually.  The ability to fill the yard with huge, wildly fragrant sages is, to my mind, one of the principle inducements toward living in Southern California. I enjoy the aromatics of our Mediterranean and native chaparral plants as much as the bees do. Here’s what we’ve got going right now–and I think I’m going to add more this fall.

Below is our native black sage, Salvia mellifera, just coming into flower. The bees like this sage, too. (They like all sages). This one arranges its flowers in little sipping cups for them. It has dark green leaves, which is less common than greyish foliage in the native sages. It brings reliable dark green foliage into the garden, and the foliage is powerfully fragrant. If you want to mellow out or soothe sore muscles, you could try throwing a a branch of this in the bath.

black sage blossom

Our other native sage, Cleveland sage, Salvia clevelandi, lives a harsh existence out in the front of our house, occupying a formerly barren strip of sun baked clay above the black roof of our subterranean garage. The heat out there has moved its time clock along at a faster pace than the mellifera in the shady back yard. The blossoms are almost spent on the Cleveland. I’m not sure what else could live in that spot, except for prickly pear, so I’m very happy it’s been so sporting about growing there. And of course, bees like it.

sage garage

We also have an expanding patch of clary sage, Salvia sclarea in our back yard. This sage is native to the Mediterranean. I planted this one on a whim, to fill a temporarily empty spot, but since then it has spread and really established itself as a player in the garden and now I find I’m just going to have to keep it and work around it. Most of the year clary sage is about knee high, with big, thick, fuzzy green leaves. But in the spring it sends up flower spikes to compete with the Salvia apiana. They are really gorgeous.

clary sage flower

The flowers are structured like the white sage flowers, but bigger. This particular shape seems to make bees giddy with happiness.

clary sage leaf

Above are the big fuzzy leaves and a flower that has yet to open. And below is the shape of the flower spikes. The spikes stand chest high, but like to fall over, like this one:

clary sage

Clary sage has medicinal uses, but I’ve not tried it for anything myself. I’ve also heard you can make fritters of the leaves….which is interesting. Of course, I’d eat just about anything if it was made into a fritter.

And last but not least is my culinary sage, tucked in with some thyme and mint, and beleaguered by the nasturtium. It’s not flashy, but its strong and knows what it’s about. It’s also indispensable in the bean pot.

culinary sage

Do you have a favorite sage? Do you have any recommendations for my next round of planting? I’m thinking about adding at least two more to the grounds of our estate.

Piet Oudolf’s Enhanced Nature

Planting a New Perspective

A garden designer has the difficult task of balancing texture, color, and space while simultaneously dealing with the unpredictability of nature. Long ago I gave up on the idea of ever being good at garden design. But help has come from an unlikely source, Piet Oudolf and Noel Kingsbury’s revolutionary book Planting A New Perspective.

High Line Park

High Line Park.

Piet Oudolf is probably best known in the US as the plant designer for the High Line park, an abandoned elevated railway turned into a park in New York City. Noel Kingsbury is a gardener and writer who has been the primary promoter of Oudolf’s work and what has come to be called naturalistic gardening or the “new style.”

It’s an approach that’s more complex than it might seem at first glance. Oudolf walks a fine line between the public’s desire for “nature” and the untidiness of the real thing. Oudolf responds with what some have called “enhanced nature.”

It’s an approach that’s pragmatic, recognizing both the need for natural ecosystems within an urban environment, while at the same time providing visual interest. Oudolf’s imprint is on the landscape, but to most people that human touch will remain on a subliminal level. It’s a brilliant “third way” strategy outside of the dualistic smackdown between the simulated nature of English style gardening and the rectilinear hedges of Versailles.


Oudolf’s plan for the Serpentine Gallery garden.

Fruitcake design
In Planting, Oudolf and Kingsbury describe their approach as like a fruitcake. The dough of that fruitcake is what Oudolf calls “matrix” plants, most often grasses, that hold together the overall design. The fruit in the fruitcake are what he calls “primary” plants, “high-impact plants chosen for strong color or structure.” Like the fruit in the fruitcake primary plants repeat in clumps throughout the overall design. He suggests a 70% matrix plant to 30% primary plant ratio. Lastly, Oudolf introduces “scatter” plants, sometimes by literally scattering seeds that will pop up seasonally and introduce spontaneity and wildness.

Oudolf and Kingsbury favor perennials both for environmental reasons (popping in annuals every year supports a energy intensive nursery industry) and for aesthetics (perennials are more prevalent in the natural landscapes Oudolf is mimicking).

Winter on the High Line.

Winter on the High Line.

The tyranny of the rose
Oudolf and Kingsbury stress the importance of choosing plants that have interesting structure throughout the year. Too often, they say, garden designers choose plants, such as roses, that flower in the spring but have uninteresting foliage the rest of the year. Oudolf’s ideal plant flowers, has striking foliage in the summer and fall and produces seed heads towards the end of the season. Those seed heads provide visual interest and food for birds and other wildlife.

I was also struck by how similar Oudolf’s gardens are to the edible landscapes of Native Californians as described by USDA botanist Kat Anderson. As Anderson has shown, the “wild” landscapes encountered by the first Europeans to visit the west coast were anything but wild. They were, in fact, carefully tended and very similar in appearance to Oudolf’s designs. You could easily combine Oudolf’s aesthetics and Native American practices to create an edible and medicinal landscapes–many of the flowers Native Californians encouraged have edible bulbs or foliage.

Oudolf’s work is cutting edge and by his own admission there are problems–such as maintenance workers confusing plantings for weeds. Kelly and I also debated how much this book can be used to understand small residential spaces–I found the ideas helpful, but most of the photographs are of large public gardens. And the plant lists are of no help for those of us in Mediterranean or tropical climates.

Oudolf's gardenin Hummelo, the Netherlands.

Oudolf’s garden in Hummelo, the Netherlands.

But these are minor criticisms–Planting is provocative and practical, with far ranging implications about the way we interact and perceive landscapes. Oudolf’s style both acknowledges the agency of humans at the same time as it provides habitat for wildlife. His approach is desperately needed in our cities and backyards.

More than any other book on garden design, Oudolf’ and Kingsbury’s Planting helped me understand how plant designers work. I can now see the problems with our garden (a lack of matrix plants), and appreciate the work of other garden designers even if their approach is different than Oudolf’s.

Black Widow or False Black Widow?

some kind of widow spider

I have a family of widow-type spiders living in my outdoor worm bin. I like spiders and all they do around the garden, and have a no kill policy toward them in general. This particular situation, however, has had me a teeny bit nervous. They hang out on the underside of the lid of the worm bin for the most part, though I’ve seen them on the surface of the worm compost once or twice. Obviously my concern is that I will touch one when opening or closing the bin, or while burying my kitchen waste.

Believing these spiders to be black widows, my options have been either to be very attentive while around the worm bin–or to roll out the vacuum. So far I’ve opted for being careful.

The thing about these spiders is that they lack the identifying spots on their abdomens, but I remembered being told somewhere that not all types show the red marks, and that males never do. Was this true? Were there other types of spiders that looked like this? After weeks of tip-toeing around the worm bin, I finally got around to doing some research. My conclusions are not conclusive, so I’m coming to you, dear readers, for help.

Wikipedia’s entry confuses me a bit:

Not all adult black widows exhibit the red hourglass on the ventrum underside or top of the abdomen — some may have a pair of red spots or have no marking at all. Female black widows often exhibit various red markings on the dorsal or top side of the abdomen, commonly two red spots. However, black widow young are believed to have at least some sort of marking on their abdomens. Adult male black widows are half the size of the females, and are usually gray or brown rather than black and red; while they may sometimes have an hourglass marking on their ventral abdomen, it is usually yellow or white, not red. Variation in specifics by species and by gender is great; any spider exhibiting a red hourglass or a pair of large red round spots on the ventral abdomen with an otherwise black shiny body is an adult female black widow.

Here is how I read this: Not all adults display an hourglass…but females often display some sort of red mark. Young and males may or may not have some kind of mark, but not red…but be careful! Variations by species and gender are significant. If you see a black spider with red markings, be very, very afraid. That there is definitely a female black widow. But really, there’s no guarantees here that other less flashy spiders aren’t some kind of dangerous, either.

This is not reassuring.

But then on the handy page Frequently Encountered Spiders in California, I learned about the False black widow.

Another European invasive, this spider seems to be displacing our native black widows in urban areas.  This spider is roughly the same size and shape as a black widow, but is brown with a faint purple sheen.

I like this false black widow option a lot. The false widows don’t have a dangerous sting.

The spiders in my box are pretty shy, but insofar as I can tell, they are all sort of an eggplant color–not that true, bad-ass black of a classic widow. Nor have I seen any red marks. (That doesn’t mean that big mama with her red marks isn’t hiding somewhere.)

So, from this not-so-great photo, can anyone tell me if this particular spider might be a false widow, Steatoda grossa, or a male black widow, Latrodectus hesperus? It’s about 1/2 inch in size.

UPDATE 5/10:  After reviewing the evidence, I believe this is a false black widow. However, my trouble are not over, because it turns out that they do have a venomous bite, apparently somewhat like a mild black widow bite. Here’s the bite intensity scoop according to UC IPM: black widows: obviously bad; brown widows: mild; false black widows: moderate.

It’s Calendula Season!

buck and calendula

Just a reminder to you all that Calendula officinalis (aka Pot Marigold) is super-easy to grow in the garden. Why should you grow Calendula? To make Calendula infused olive oil, of course– as I’m doing above, with inevitable feline assistance.

Well, that’s why I grow it. Calendula infused olive oil is the base of all my lotions and potions, because it is such a potent healer of dry, itchy, burnt or otherwise irritated skin. I’m using it right now to treat my sunburn–which is what made me think of this post.

But outside of this, it’s an all around useful herb.  Here’s a couple of profiles to check out if you need convincing: Plants for a Future;  University of Maryland

It takes about 60 days for Calendula to reach maturity from seed, so if it’s spring where you live, now is a good time to plant it. Note that Calendula is a happy volunteer. Once you plant it, you may never have to plant it again. The volunteer flowers are not as big and fancy as their parent flowers–they revert to their wild form quickly–but they work just as well.

I like Calendula so much that I’ve already written a whole series of posts on it: