a new weed

This past winter I was noticing a weed popping up all around the yard that I hadn’t noticed before. I was mentioning it to John, and added, “I’m not sure what it is, though think it could be some sort of euphorbia.”

Then in the gently tactful way spouses have of correcting you and pointing out your blind spots he quietly cleared his throat and pointed to one of the four young potted plants we have around the garden of Euphorbia lambii, one of my dry garden-adapted plants from the Canary Islands. “Maybe it’s that?”

Uh, like duh. What else would it be?

Last year was the first that these plants bloomed, and this spring they bloomed with a vengeance. During sunny weather over the last few weeks I’ve heard little popping noises from the direction of the plants, and have come to the conclusion that the sounds were that of seed pods exploding and jettisoning the dust-like seed everywhere.

I may come to regret the day I introduced these to the garden, which according to my records is March 9, 2008.

Speaking of weedy plants, here’s another surprise seedling from the garden, a little baby red fountain grass, one of three seedlings I noticed this year. In recent years the related green fountain grass, Pennisetum setaceum has become a noxious (though stunningly beautiful) weed and has landed high on virtually every thou-shalt-not-plant list issued for California. But many people gave a by to this related red plant. It was often pushed as being sterile and incapable of reproducing by seed, a piece of misinformation even I relayed in this blog. (I’ve corrected that earlier oops in case anyone reads that earlier post.) As you can see here it can reproduce by seed, though this form doesn’t spawn the same way regular fountain grass does. Nor is it immediately the same monster pest that feather grass (Nassella tenuissima) can be.

Poking around the web I found an updated plant description at San Marcos Growers that includes some interesting background on this plant:

Recent work in preparation for the grass sections of the Flora of North America, which will include naturalized and cultivated grasses, indicates that the name chosen for this plant will be Pennisetum advena or perhaps P. x advena. Dr. Joseph K. Wipff, previously with Texas A&M and now a turfgrass breeder, wrote the section on Pennisetum and has indicated that Red Fountain Grass is most likely a cross between P. setaceum and P. macrostachys (AKA ‘Burgundy Giant’). As a hybrid the name would most appropriately be Pennisetum x advena ‘Rubrum’. The latin word advena means “newly arrived” or “stranger.”

So is it safe to plant this form of fountain grass? Here’s my thinking: Hybrids between species are often sterile. (Think of mules, the offspring of a horse and a donkey.) But every now and then something happens that allows the hybrid to reproduce. Sometimes the seedlings will be just as nearly sterile as the immediate parent, but other times a mutation could render the seedling entirely fertile. In that latter scenario the nearly-sterile fountain grass could turn into something with the ugly invasive potential of its Pennisetum setaceum ancestor.

In other words, today I would be cautious and not plant it. Unfortunately, almost twenty years ago, we designed the front yard around a big mound of the stuff. The plants look stunning and move graciously in response to the breezes. Their size is perfect for the spot, and their red color is unmatched among other grasses. Every now and then I look at other options, like those recommended in the Don’t Plant a Pest brochure put out by the California Invasive Plant Council. But these lists often fall short in the alternatives they offer and end up reading like, “Cheesecake is bad for you. Would you like to eat this delicious raw rutabaga instead?” So…I’m still looking for the perfect replacement plant–hopefully some sort of native, but in the meantime I’m pulling the occasional seedlings.

10 thoughts on “a new weed”

  1. Now there’s nothing wrong with raw rutabaga. C’mon you know it’s good for you. I’d be wary of any plant that supposedly can’t reproduce. In general I think the sterile label is stuck on there to sell plants that people would otherwise complain about. Supposedly there is a sterile broom they sell here. I wouldn’t bet on it. It’s a shame that all the most beautiful grasses seem to be incredibly invasive though.

  2. I gotta join Brad in defense of raw rutabaga here. Chock full of antioxidants. I don’t really see the pennisetums reseed up in northern california so much, not like mexican feather grass at all. Doesn’t really win you any style awards up here though. Some of the euphorbias have naturalized and reseed pretty heavily. The volunteers seem slow at first, so I haven’t been too afraid of them. It’s good to know that E. lambii is a reseeder.

  3. That was quite an analogy you came up with. Unlike your other commenters, I’m certainly not going to defend rutabaga, raw or otherwise. (I don’t think I’ve ever actually eaten rutabaga or even a turnip of any sort, but as far as I’m concerned, pretty much ANY vegetable other than potatoes and corn is totally inedible.)

    I’ve never noticed the “Don’t Plant a Pest” brochures being so dissatisfactory, but that’s probably because I’m not familiar enough with most of the “pest” plants to know what their appeal is. I think that’s the easiest way to be able to avoid cheesecake – don’t find out what it tastes like in the first place.

  4. Planted fountain grass, then began to realise it was a mistake. And years later I still remove the seedlings. Bought the red, was told it is not as invasive. But it grew HUGE, so dug it up and now have 2 small bits, confined in pots.

  5. Ah, yes, Euphorbia. I’m just so glad I took that out (actually, I got professionals to take it out). One visit to the emergency room because I washed a tiny amount of the sap from my eyebrow into my eye was more than enought. “Euphorbia?” said the nice doctor, and was quite pleased I’d brought a sample ’cause he’d never seen one, though he gets the victims all the time. Then again, I still have a few little ones (1 foot high) that don’t seem all that invasive…

  6. The whole issue of how to grow non-native plants without inadvertently introducing invasive exotics into the local ecosystem is one I struggle with as a gardener. I think I’m coming to the conclusion that the appropriate stance for gardeners in relation to introducing new plants into the garden is one of humility and conservatism. By humility, I mean that we have to recognize that we don’t really know what we’re doing, that gardening is a big experiment, and be cautious. By conservatism (not a characteristic I usually embrace :-)), I mean that we shouldn’t always be rushing out to get the latest thing; there’s a lot to be said for tried and true plants that have been grown in local gardens for years (or even generations) and that have not turned out to be invasive. To get information for the U.S. on plants that have already been identified as invasive (and where) see the Invasive Plant Atlas of the United States (http://www.invasiveplantatlas.org/index.html).

  7. Sometimes those euphorbias can be weedy even though they are such stunners in the garden. Maybe you could deadhead this year? I hope it works out. I myself stay away from pennisetums. I don’t know why but I’ve associated them with self seeding though some say miscanthus self seed I’ve not had that issue here. Now if I could just find a way out from under snow on the mountain and creeping monkey grass…

  8. Please pass the cooked rutabagas, my very favorite.

    Invasives and their replacements vary from one coast to the other. I never thought of pampas grass being a fire hazard, just overblown and ugly for a personal landscape. Now I have another reason to dislike it.

  9. Brad and Ryan, maybe I’m being too harsh on rutabagas. It just sounded less appetizing than the word “turnip.” If there ever was a forum where you shouldn’t trash rutabagas, it’d for sure be a gardening site.

    Gayle, not learning to love cheesecake is probably the best way to go. It’s easier to start on the right foot and make do with all the other remarkable plants that are out there to use. I probably eat more of my veggies than you, but I still have a soft spot for cheesecake. All bad things in moderation.

    EE, my red fountain grass has formed a large mound, but it definitely doesn’t get as monstrous as for people who water it regularly. Someone I know watered hers daily for a while, and the plants were immense.

    TM, there’s a local native euphorbia (E. misera) that I’ve been interested in trying. I wish it were a more comely plant, though it’d look just fine in a dry desert-scape. I’m sorry you had the awful/classic sap in the eye encounter. I hear about it enough that I’m always careful when working around them.

    Jean, I’ve been trying to limit more of my plantings to more local plants. But they’re often both hard to find and don’t always have the quick self-starting ability that the popularized exotics do. I suppose these exotics’ ability to out-grow many of the local is as good a reason to avoid them where possible. But it really is hard for this curious person to limit my curiosity to what I can see in public gardens.

    Tina, I began deadheading this year and am hoping for an easier year next time, but I know I’ve waited too long. Snow on the mountain and monkey grass haven’t been invited to my garden, and following your advice they won’t get past the bouncer.

    Wendy, hmmm… rutabaga cheesecake? (Sounds like county fair food…)

    Nell Jean, maybe I’ll have to give rutabagas another try, decades later… Pampas and “personal landscapes” definitely seem at odds, as you mention, since they’re such huge beasts. Some gardens that still have it look like people keeping mastiffs in tiny New York apartments–way out of scale.

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