Yes, dandelions. They were all over. I talked to a ranger nearby who said that the park has a big problem with invasive species. He wasn’t a botanical expert, he said, but he thought there was a true wild dandelion, as well as the garden version. Unfortunately, this to me looks like the garden version. They were all over the park, as well as all over Idaho on the way there.
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!
After my last post I did more research on controlling English ivy. Beyond the commonly-quoted advice to spray with herbicides, or to attempt the mechanical removal that is occupying me these days, I saw an interesting idea for a new but as-yet-untested biological control Nothing immediately useful, unfortunately. And then I started to see techniques that could only be dreamed up by people like me who’ve been spending too much time fighting off Hedera helix.
From the folks at the University of California, in a discussion of ivy, comes:
Prescribed burning: An extreme method that has been used with some success is to burn ivy plants and resprouts with a blow torch at regular intervals; the energy used by the plant to regrow will eventually be depleted. Obviously, this approach requires considerable caution.
And from Organic Land Care.com comes:
Another more drastic method has been to use a blow-torch to repeatedly blast the plant with a hot flame. By repeatedly exposing the plant to high heat, this method is intended to exhaust the H. helix of its energy so that it is unable to multiply or produce berries for reproduction (Reichard, 2000).
So…fatigued of doing things the old-fashioned way, I went to the garage and got the blowtorch. After aiming the flame at some ivy leaves they began to writhe and smoke in a most satisfying way. Soon the leaves started to burn, which surprised me since ivy is one of the plants that shows up occasionally as a recommended plant for firescaping. As the leaves burned, some of the dead grasses around them started to catch fire. Just a little more heat and I’d have had a little brushfire started. Hmmmm. Maybe it’s not such a good idea, I started to think, looking up at a wood fence not more than two feet away. Damn, it felt good, but I ended the experiment right then and there–it probably wasn’t a good idea to burn down the neighborhood!
In my more active anti-nuke activist days one of the more compelling arguments against nuclear power was that some of its byproducts were so long-lived that they would remain lethal for longer than human civilization has existed. Plutonium-239, for example, has a half-life of something like 24,000 years, and even a tiny particle of it could prove dangerous to a person.
I was thinking about that during my weeding exercise this weekend, dealing with a neglected corner of the garden where the neighbor’s English ivy had crossed over and under the fence and set up a stand that had spread 20 feet or more into my yard. In the course of its invasion, it had contributed to a low brick retaining wall being pushed over.
The wall the ivy helped push over
I hate to use stuff like Roundup in the yard, but I tried it on the ivy a couple weeks ago. Some of the weeds around it shriveled to brown ghosts of themselves, but at best the ivy showed a little burning around the edges of the leaves. I’d tried Roundupping the ivy before, with similar minimal results. Ivy really seems like the thing that wouldn’t die. Some online sites have guidelines on how to get rid of the stuff, but none of them seem to guarantee easy control. (A couple of the sites I looked at: Southeast Exotic Pest Plant Council Invasive Plant Manual and the Plant Conservation Alliance’s “Least wanted” pages.)
I wasn’t looking forward to the alternative of digging it out by hand, but digging it out by hand was the chore that ate my weekend. And it’s a chore that’ll be occupying at least a couple more. The job is extra-awful in that even a little piece of ivy runner left in the ground could grow roots and set up a whole new colony. You have to be sure to dig down the foot or so that the runners can travel at, and you need to be sure that you’ve rid the patch of all the alien ivy life forms before you move on to the next spadefull. It’s like vegetable plutonium in that any little bit left in the ground could prove dangerous for future generations. Nasty, evil stuff.
If my mantra of my teen years was “No nukes!” the mantra of my current gardening life has to be “No Ivy!” Frank Lloyd Wright was famous for his quote that went something like, “Doctor’s can always bury their mistakes. Architects can only plant ivy.” Well, friends, doing that would be the greatest mistake of all.
Lots of times I’m glad to be living in Southern California where winters are mild and things hardly ever freeze. Today’s one of those amazing winter days: brilliantly sunny, warm–and it’s the middle of February. But there are down-sides. Thousands of them.
What I’m talking about of course are the weeds popping up everywhere in the yard. After a wet January, as the days begin to warm, nothing has a stronger life-wish than the seeds that have been lying dormant in the soil. So now there are wild patches of grasses, oxalis, spurge, dandelions and all sorts of other green matter making a break from the cool security of the earth. Not that I blame them. I’m starting to feel motivated myself to break out of the heated house and spend some time in the sunshine outside. But at the same time I’m starting to think a lot about one of the quotes I listed last time, a couple lines by David Cooper:
The life of a serious gardener is not one that, as it happens involves some gardening. Instead, it is one partly define by the structured, regular activities which are imposed once the decision to grow and to garden is made.
In cooler climates, even serious gardeners get unbroken weeks indoors to pore over plant and seed catalogs full of more blooming things than you’ll see in any botanical garden. That’s an activity I love doing as well. Today lots of these catalogs are online, giving the smaller grower an opportunity to showcase their plants, and the offerings are as spectacular as ever. A couple of interesting ones I’ve been looking at lately:
Sarracenia Northwest (cool carniverous plants)
Las Pilitas (California native plants)
But the weeds wait for no one. Jeez, sometimes I wonder if I have the strength to take on a patch like this one, a severely underloved corner of the garden guarded by a spiny pachypodium and overrun with the neighbor’s ivy:
And then there’s this little patch of dirt that until recently held some berries that had been overrun with all sorts of invasives. I took it down to bare earth a month ago, and the weeds are starting up in it already:
But what can you do? Let it go back to nature? Pave it over? For a garden with not enough planting space for those amazing plants in those plant catalogs, niether of those seem like reasonable options. So…what will I do with my weekend? I’m sure it’ll have something to do with weeding….