Wednesday, June 28, 2023

Wild & Weedy Wednesday: Tolerable weeds

I'm joining Cathy of Words and Herbs this week for her "Wild and Weedy Wednesday" meme.  I've got a multitude of true weeds in my garden this year.  If there's a positive side to a prolonged drought, it's that there's fewer weeds to pull.  This year we've had more than five times the amount of rain we had in the prior water year (21.69 inches versus 4.12 inches in 2022) and it seems I spend a quarter of my time in the garden pulling weeds.  If I factor in the time I spend thinning out the more decorative, albeit weedy, plants I tolerate in my garden, it's probably more like half my time. 

This post focuses on my five favorite "tolerable weeds."  None of these plants are native to coastal Southern California but all have naturalized here.  One has been officially designated as invasive in California but all are aggressive spreaders.  In spite of this, all are commonly sold by local garden centers.

The first is Centranthus ruber (aka Jupiter's beard), arguably the most vigorous and the most decorative of the lot.  Native to the Mediterranean area, it's been found in wild areas in various western states of the US, including California.  According to Wikipedia, it tolerates alkaline soil and is often found in rocky areas below 200 meters in elevation.  It isn't classified as invasive but I see it along the roadsides here and I've noticed it popping up in many of my neighbors' front gardens.

I didn't introduce it to my garden.  I found it growing in my northeast side garden when we moved in.

However, I did transplant several divisions from that area to my back slope, which was relatively empty before I began developing it in the early years of our residence.  It took off with a vengeance despite very little irrigation.

In my climate, Centranthus prefers our cool spring season.  As temperatures rise, the plants quickly go to seed as shown here at the bottom of my back slope.  I can't deadhead them fast enough.  I need to get down there to cut the flower stalks to the ground but fear of the fire ants has led me to put off that chore.

 

Erigeron karvinskianus (aka Mexican fleabane and Santa Barbara daisy) is native to Mexico and parts of Central America.  It's not officially classified as invasive but the Plant Right site rated it a moderate potential risk in California, especially if it receives moderate water.  It was here when we moved in and it readily moves itself around without any help from me.

In my northeastern side garden, it's intermingled with English ivy (a plant that is classified as invasive in California), making it more difficult to manage

It's a lovely graceful plant when it's getting sufficient water but it starts to look sad and weedy once the rain stops (as shown on the left).  The plant on the right, mingling with a Teucrium aroarium, is doing better in partial shade.

 

Geranium incanum (aka carpet geranium) is a South African native that has naturalized in California.  Like the Erigeron, it moves itself around, although in my garden it's most prevalent in the same areas preferred by Centranthus ruber.  It's not classified as invasive but it's said to get by without irrigation in coastal areas.

In this photo, it's sharing space with Erigeron karvinskianus

The Geranium most often "hides" under taller plants, slowly making its way into the sunlight before it blooms.  In the photo on the left, it's growing up through a mass of rosemary.  In the photo on the right, it's growing up through ivy on the upper edge of the back slope.

 

Unlike the other plants covered in this post, Lobularia maritima (aka sweet alyssum) is classified as invasive by the California Invasive Plant Council.  It's native to the Mediterranean basin but it's naturalized here.  It's said to like sandy soil like mine.  I'm not sure I've every visited a local garden center that didn't have six-packs of this plant in stock year-round.  I admit that I've often purchased it for use as a filler in planted containers.

I don't go out of my way to photograph the ever-present alyssum but this wide shot taken of my back garden in early May provides a good idea of how widespread it is in the landscape.  All of the alyssum shown here was self-planted.

The foreground of this shot, taken at the bottom of the back slope, provides an idea of how much space it covered there.  Pulling it up isn't simple.  The plants have solid taproots and their side roots often extend over a good foot or more.

One of the few closeup photos I've ever taken of the plant.  They love to self-seed between and around flagstones.

 

The last of my attractive weeds is Oenothera speciosa (aka pink evening primrose).  Native to areas of the Midwest, Texas, and northeastern Mexico, it's naturalized in 48 US states but it's not considered invasive, although I've heard many gardeners complain about its spread.  I didn't introduce it here.  It spreads itself around more lightly than the other plants described here.  To date, it prefers my northeast side garden and back slope.

The top photo on the left shows the flowers in my northeast side bed.  The group shown on the lower left was photographed at the bottom of the slope.

It even self-seeds in densely packed gravel

 

Visit Cathy at Words and Herbs to see which wild and weedy plants she's featuring this week.



All material © 2012-2023 by Kris Peterson for Late to the Garden Party

26 comments:

  1. Additional rain encourages all plants to grow, weeds included. I spent MANY hours pulling weeds, trying to get them before they go to seed. Most challenging in my garden is Oxalis, though I'm at least as determined as the weed.
    Sweet Alyssum is an annual in my climate. I love it's scent.. but if it's classified as an invasive plant, why are nurseries still selling it?
    Chavli

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    1. I've got plenty of Oxalis weeds this year myself, which I don't hesitate to pull, Chavli. The only exception is Oxalis triangularis but it's in a pot and has never tried to spread any further.

      It's amazing how many plants on the official list of invasive plants in California are actively sold. English ivy (the bane of my gardening existence) is one but Echium candicans (the non-variegated form) is there too. At least Echium seedlings are easy to pull out if they appear where you don't want them in the garden but I expect they're pushing aside native plants in wild areas. As Lobularia/alyssum is so commonly used, I expect there'd be a hue and cry from customers if the garden centers pulled them. I recall that the former head gardener at the local botanic garden made an active effort to eradicate the plant. I can't remember seeing it on my most recent visits but then I tend to tune it out except in areas where it tries to take over my own garden.

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  2. I love Centranthus ruber and could never manage to grow it even in my old sunnier garden. So it is fascinating to see how it behaves for you. I've thought about that pink evening primrose, but now I will think again and check how it does here. I have at least one invasive in my garden and it is true that so many problem plants are still out there to buy.

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    1. The California Invasive Plant Council list was a bit of a revelation for me, Linda. Of course, it refers to the entire state and, given the size and variety of ecosystems within California, it can be a little deceptive. Many of the plants there are on a "watch" status, which is the lowest level of concern. Lobularia is in the middle level, "limited", category, which means it's a significant concern in certain areas. Stipa (Nassella) tenuissima and Lantana camara, both actively sold locally, are also on the "watch list." There's even a Grevillea on the list, albeit not one I have in my own garden.

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  3. That was all so interesting for me Kris! You know I grow Centranthus here. It spreads here too! But I also grow that Erigeron as it is very hardy. And the Lobularia is a standard in summer containers here, but obviously isn't hardy enough for planting in the ground. It looks lovely in your garden along the paths! I love that Geranium, and would certainly let that roam… also not hardy enough for us here though. But I do have wild Geraniums that spread. And the Evening Primrose is something I have grown in the past and would love to grow again. All in all, your 'tolerable' weeds are delightful. Thanks for linking to my post, and perhaps you will share some of the less tolerable ones one week too. ;-)

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    1. I expect that "real" winters quickly kill off the Lobularia/alyssum but we don't even get freezes so it has no problem running amok here, Cathy. I just cleared out my sweet peas and found a virtual blanket of Erigeron karvinskianus underneath them - apparently they like drip irrigation. I'll see if I can come up with some more annoying - but photogenic - weeds ;)

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  4. I always find it interesting to hear what others define as weeds. I've tried many times to grow Geranium incanum--with no luck. Geranium robertianum, on the other hand, is a noxious weed.

    We had Centranthus appear in our garden but I got rid of it quickly because it was an aphid magnet.

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    1. Aphids on Centranthus! I've never seen them go after those plants at all here. Invasive plant lists covering an entire state, especially one as large and varied as California, seem to be misleading. It might be more helpful to see lists of the factors that can make individual plants invasive.

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  5. Love this post with these beautiful flowers!

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  6. Tolerable weeds...I like that perspective. I certainly have plenty of those here. Some are non-natives that just showed up, but they aren't particularly invasive. Others are prolific native plants that some people might consider invasive. They do perform well in all kinds of weather, though. ;-)

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    1. After the heavier-than-usual rain this year, the Lobularia/alyssum is bordering on invasive from my personal perspective but the other plants identified in this post haven't become pests, at least not yet. The Mexican feather grass (Nassella/Stipa tenuissima) in my garden is closer to getting an eviction notice.

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  7. Pretty weeds they are too. I don't grow centranthus because it is a bit too enthusiastic here as well. Erigeron seeds around in my garden but I love it. I would love to have Alyssum popping up everywhere, I love its honey scent.

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  8. Forgot to say, that last comment was Chloris!

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    1. Well, alyssum IS popping up everywhere here, or at least it was after this year's rains. I'm not sure even pulling out entire taproots is going to make any difference at all next year either, Chloris ;)

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  9. So many of weeds are escapees from our gardens. I am pulling out bachelor buttons and sunflower seedlings by the hundreds this year in order to plant my vegetables. I attended an invasive species conference in the Spring and in Alberta alone invasives cost the government over 2 billion dollars/year. I imagine the costs are similar, maybe more in warmer climates, everywhere else as well.

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    1. Yes, I imagine those escapees have a big impact on the agricultural industry too, Elaine. What I find odd is the difficulties I've faced getting known self-seeders like sunflowers - and California poppies! - to self-seed on even a minuscule level in my own garden. One of those gardening mysteries.

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  10. FIRE ANTS! I don't like the sound of that. The only one of the plants you mentioned that actually scares me is the english ivy. Ugh, it's difficult to pull and you never know what's hiding in there. Alyssum is pretty and smells so nice, I don't mind it spreading a bit.

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    1. Well, to add to your nightmares about english ivy, tz, that's exactly where I suspect the fire ants on my back slope have their nests! I never even knew fire ants were present in SoCal until the first time I ended up with over 2 dozen "gifts" from the nasty buggers. They bite AND sting and most of those create itchy pustules that take a long time to clear up. I usually avoid sprays of any kind in the garden but my husband did spray at the bottom of our slope last year after what I think was my 3rd round with them.

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    2. I avoid spraying, too. But I don't blame you, that sounds horrid!

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  11. Naturally your weeds have lovely flowers! Oxalis and shotweed (Western bittercress) are the two that want to take hold here and neither have much showy flower power.

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    1. I'm not familiar with western bittercress but I've got plenty of Oxalis weeds, Loree. Only Oxalis triangularis behaves itself.

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  12. Interesting survey. The neighbor planted a bunch of Centranthus ruber but it died and vanished in the drought. I have to think about the "tolerable" part. Not much of that--here we get the "intolerable" ones!

    Honey bees will go for the Lobularia. I let a few grow and flower here if they have a compact habit, but pull 99% of it.

    The local nature park has a problem with Brassica nigra, common name "black mustard", which does two bad things: it successfully crowds out native plants, and it significantly worsens wild fires by growing thick and being very flammable. I have had a few come up in the garden this year but pulled them quickly, long before they flowered.

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    1. I clearly wasn't ruthless enough in pulling the Lobularia seedlings early in the season, HB. We have the same mustard weed all over the peninsula. It eventually gets cut to the ground but not nearly early enough in most areas to reduce self-seeding. And it's a fire hazard! I don't have any growing in my own garden but there's a vacant lot up the street that was covered in it before the absentee owner performed the mandatory brush clearance earlier this year. (Who leaves a one+ acre lot with a harbor view vacant for over 12 years anyway?!)

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    2. Oh my gosh! We saw fields full of Brassica nigra on our trip to northern CA. I thought the black seed heads were incredibly attractive and almost brought some home. Fortunately, I realized it was invasive based on its distribution and decided to leave it there. Glad to have an id on what it was.

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    3. You are lucky indeed, Jerry. It's hard to get rid of!

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