Tag Archives: Brassica nigra

…and some not so garden-worthy

You could probably gather together six gardeners and get six different opinions of what would make a plant garden-worthy. But I suspect there might be somewhat more agreement on certain other plants that probably shouldn’t be included in a garden. Here are some encounters from Sunday’s trip to Tecolote Canyon that would fall easily into most people’s less-than-desirable category.

tecolote-canyon-poison-oak

I’ll have to admit to actually liking this plant to the right. During the winter it drops its leaves and is an attractive thicket of upright or sprawling branches. This time of year it starts new growth that has this warm red-brown coloration. It’ll flower soon, and then set some loose clusters of white berries. Pretty, yes, and native, and important to wildlife. But this is poison oak. Maybe not the best choice for small backyard gardens…

Most of the rest of my list below is comprised of exotic plants that have staked a claim for themselves at the expense of the native species. Different locations have their own list of invasives, so what you see below is tailored to Southern California. Some of these plants could be good choices for other locations. Others would be trouble almost anywhere you grow them.

[ At this point I’d like to dedicate the rest of this Friday the thirteenth post to Outofdoors, who last month devoted her Friday the thirteenth post to invasive plant species. ]

tecolote-canyon-pampas-and-iceplant

tecolote-canyon-fountain-grass

I won’t go into too much detail about this troublesome trio. People have been working hard to get the word out on pampas grass, green fountain grass, and iceplant. The grasses, in particular, can be gorgeous things in gardens, waving in the breeze and lending their dramatic form to groups of softly mounding landscape shrubs. You can see why people want to grow them. But are they garden-worthy in Southern California?

All three of these quickly check out of people’s gardens and make for the wilds. I found both grasses and plenty of iceplant escaped into the canyon, here on this hillside and in other spots. So, as pretty as they can be–and I consider this drift of fountain grass in the second photo to be particularly poetic–these three would be better left in their native lands, or grown in climates where the weather might limit their spread.

tecolote-canyon-wild-onion-flower

tecolote-canyon-wild-onion-plants

This is the first flower I saw this season on the local plants of onion weed (Asphodelus fistulosus). The first time I saw it I thought it was a wildflower and wanted some for my garden. In full bloom the stalks of white flowers are an impressive sight. But they do spread like crazy. Not a good choice for the garden.

tecolote-canyon-teasel-and-mustard

This combination of plants looks as impressive as any planting assembled by practitioners of the New Perennials garden movement. But once again, the plants aren’t really welcome additions to the canyon. In the foreground is teasel (Dipsacus sp.), a plant with excellent year-round architectural structure but having invasive tendencies that are considered “Moderate” by the California Invasive Plant Council (Cal-IPC). Here it’s set against a background of last season’s black mustard, a problem in these parts since it was introduced by the Spanish in the eighteenth century. The Cal-IPC only considers the mustard’s ranginess to be of “Moderate” concern, but also states: “Primarily a weed of disturbed sites, but can be locally a more significant problem in wildlands.” I’d say it’s a more significant pest locally.

tecolote-canyon-fennel

Fennel can be attractive in the herb garden, but like the rest of the invasives in this post, this is another plant that gets around. Its overall undesirable impacts are considered “High” by the Cal-IPC. If I see fennel offered in the local nurseries it’s usually the bronze colored strain. It’s less vigorous, but all forms are considered invasive. I do wish this were a better choice for gardens because it hosts swallowtail butterflies, but at least there’s plenty of swallowtail food out in the local canyons. The butterflies won’t starve. Okay, I’ll pass.

tecolote-canyon-pepper-tree

Say “Old California” to anyone who’s lived in these parts for long, and this plant will probably come to mind. The Brazilian Peruvian pepper tree forms a gorgeous tree with long, delicate leaves that move any time there’s a breeze. But unfortunately the plants develop berries that the birds find irresistible. While the Cal-IPC considers their threat to California to be only “Limited,” there are plants that would be better choices.

The Australian peppermint willow (Agonis flexuosa), although not a native plant, is a good drought-tolerant substitute that looks a bit like the pepper tree but doesn’t share its invasive tendencies. If you must have a delicate weeping tree that says “Old California” but don’t mind a lilting Australian accent, this would be a better choice–and you can get varieties with either green or dramatic black foliage. Or you could give up altogether on the colonial look and go in for any of the truly native trees. It doesn’t get any more “old California” than that.

As I reread this post I’m struck that I’m probably not doing a particularly good job of discouraging people from growing these plants. I keep going back to the beautiful redeeming qualities of these invasives, and I guess that’s why they continue to be such a problem. The mind tells you they might be bad news, but sometimes it’s hard to say no.

With this last image I leave the plant kingdom and turn to another species that’s native to the local canyons. This one I think you’ll definitely agree you wouldn’t want around. I won’t assume that you like snakes any more than I do, so if you want to see the picture you’ll have to click HERE.

Still, who among you doesn’t think baby animals are just the cutest things? Now, everybody, say “awwwww”… This is a little baby southern Pacific rattler, probably no longer than my forearm and too young to rattle. I’m deathly afraid of snakes but managed to fend off the fear to snap the picture and watch the snake as it coiled itself defensively and make like a sidewinder, sliding backwards into the grasses.

I have to respect these animals since they do wonders to keep down the rodent population. And they’re every bit as native as the poison oak I showed earlier. But after having had one of these in the backyard facing off against my cat, I’ve definitely decided this is another species that’s not garden-worthy, at least in my enclosed little space.

I admit it, I’m a wimp. Nature isn’t always convenient is it? But throw out the rattlesnakes and pampas grass and black mustard and fennels and you’re still left tens of thousands of cool and friendly selections to invite into the garden.

wild and out of control

All over town here in San Diego you see the black mustard plant, Brassica nigra, now approaching the end of its blooming period.

The undulating yellow mounds of it doing its thing are a spectacular sight, so much so that Napa Valley, up north in the wine country, has an annual Mustard Festival that’s just come to its conclusion. The festival host the expected Napa wine and food offerings, and also hosts contests in photography, art and cooking with mustard. In addition to how the plant looks, it has an interesting history, as told by Napa pioneer Calvin Chesterfield Griffith, quoted on the Mustard Festival’s site:

This is the story of our early California when it was only a wilderness, with great quantities of trees, beautiful plains, all kinds of wild animals and birds; many, many Indians, and no white men at all.

Father Serra had come from Spain to Mexico to spread the religion of Jesus Christ, and hearing about this beautiful, vast country to the north, decided to explore it. With a few faithful followers and Indian guides, he traveled north through what is now our glorious and loved California. As he traveled he scattered to the right, and to the left, the mustard seeds which he had brought with him from Spain.

The following year, as they returned south they followed ‘a ribbon of gold;’ and following that path again Father Serra established his ‘Rosary of Missions,’ beginning in San Diego and ending in Sonoma.

It’s an appealing, romantic story, but it also sidesteps the fact that the mustard has invaded much of the West, and can be found in most of the United States. As a robust winter annual, it can out-compete most native plants, particularly in disturbed locations, and form virtual monocultures that prevent other plants from getting a foothold. The pictures above were taken a few blocks from my house, in Tecolote Canyon. Because of abundant moisture earlier in the year, the plants were well over my head in spots, easily seven feet tall.

To the left is a picture of a part of the canyon where the mustard hasn’t taken over. It’s a good example of coastal sage scrub, rich in plantlife and alive with birds and insects. The white-flowering plant in the foreground is black sage, Salvia mellifera, blooming up a storm, with yellow deerweed (Lotus scoparius) behind it. So what would I prefer–a rich ecological mix of plants that host a range of animal life, or a showy burst of color that nourishes almost no animal life and is about to dry out to a wildfire magnet?

Alert on a new invasive: Cousin Jenny, a new Master Gardener in South Carolina, alerted me to a new invasive plant, cogongrass, a plant that’s being listed as a treat even worse than the suffocating kudzu. Here’s a link to a story in the Beaufort Gazzette. Like the black mustard, it’s an attractive plant, but it’s also serious bad news.

More on weeds and invasives: I’ve been leafing through Weeds of California and Other Western States, by Joseph M. DiTomaso and Evelyn A. Healy. It’s a sumptuous two-volume set, a coffee-table book of weeds if there ever was one, with 3000 images of the 750 evil species it lists. It also comes with a CD-ROM of the images in the book that can be used without royalties for educational purposes.

In addition to the 750 nasties, there’s a table in the back with potential future threats from plants that are just entering the ecosystem. The book leans towards the technical side, but there’s a handy glossary and index. It took me 20 minutes to figure out that the annoying grass coming up in spots around the yard was tall veldgrass. But with other species I was able to go right to the offender.

I found it striking that a huge number of the weeds–like the black mustard–were of European origin, likely brought over by settlers from there over the past centuries. Controls have since been erected that help reduce the entry into the country of plants that might prove invasive. However, with people, products and produce jetting all around the world these days, it’s inevitable that there will be waves of invading plants from regions other than Europe. The cogongrass that’s of concern in the South, for instance, comes from Asia.

As I wander around the yard inventorying the plants coming up in the crevices, it’s weirdly comforting to know that my yard is contributing to preserving the earth’s biological diversity–though unfortunately I’m not necessarily helping along the species that really need it the most!