The "Belts and Suspenders" strategy of my least favorite weed

At the California Nursery Historical Park, our rose beds are awash with the "Devil Bulb". This crafty weed confounds us at every corner. Nothing seems to stop it. I call its strategy "Belts and Suspenders", because it profusely propagates by bulb and by seed. And it seems to grow year-round and to flower year-round and to make bulblets year-round.

This "Devil Bulb" has been in our garden for a very long time as you can see from the 1997 Mercury News article below. I asked 93+ year-old nurseryman, Bruce, if it was in the garden in his time and the answer was yes.

Is there any hope?





It's a jungle out there

Typical scene in our rose beds

Some of our gardeners specialize in this insidious weed. We love them for that. I wish they could do something else like plant flowers. 

←This is their warped view of our garden - a tangle of long strappy leaves.

The park gardeners in 1997 mis-identified it as an onion. That is a different noxious week. But there is not onion smell.  That is, unless you spend 2 hours buried in it, in which case there is a faint smell of oniony garlic?

This is Nothoscordum gracile (wiki) a plant from South America. The Useful Tropical Plants website even sings its praise about its "sweet lily-like perfume" and gives it two bananas for edibility. (I would check this out first before attempting to eat.)

And I wouldn't give two bananas for anything like this. (A banana gets 5 bananas, in case you wondered about the scale.)

The War of the Roses

Article from 1997

The article describes the war that the gardeners fought in 1997. "War is Hell" and many of this group of volunteer gardeners finally surrendered and went to Shinn Park instead.

People complain about Bermuda Buttercups, but they have not met the "Devil Bulb". This SFGate article describes it as best as I've seen.

We have heard that the Morcom Rose Garden folks also have it. They dug up a whole bed, discarded the dirt, replaced it, and it still came back.

One of my classmate's neighbors has a whole field of it.

In March, it's making bulblets and blooming

Strategies of the "devil bulb" - Belts and Suspenders

• Belt/Bulblets - We'll call the little bulblets the belt. From one bulb, many little bulblets form. They break off easily. These come back as tiny plants in large quantities. Gardener strategy: don't even try to remove all of the dirt. You can discard some dirt, rather that risking the little dirt-colored bulblets falling out. We have more where that comes from. We can replace it with compost.
• Suspenders/Seeds - Unlike some plants that have an equally fabulous strategy of bulblets, like Bermuda buttercups, the "devil bulb" sends up flowers nearly year round and from each flower a large number of seeds (100?) are created. Gardener strategy: Remove the flowers before the seeds ripen. If you remove this year's seeds, that will reduce next year's little seedlings. Repeat repeat repeat.

Strategies for the gardeners

• In fall when the seeds start to sprout, rake the little seedlings and remove. Much easier at this time of year than later when the ground is hard.
• Focus on one bed - Some of our DB eradicators have focussed on one bed and have made great strides.
• Focus on beds with the fewest - Start in the remote locations and work back to ground zero. Some beds are just full of the "devil bulb". Don't start here. Start where there are one or two plants and dig those up completely. If you ignore those beds with one or two plants, next year there will be 30. The year after 600. The year after that even more and more.
• Smother - We put down cardboard and topped with mulch. Maybe this will slow it down. Maybe not. We see the plant poking up through the mulch. Perhaps the little seedlings will exhaust themselves trying to get to the light? The cardboard eventually came up in pieces making a mess. We have overhead watering, so cardboard+mulch is not the answer. How do the roses get watered? Perhaps 10% of the water that is used ends up on the roots. And if the cardboard is close to the trunk of the rose, that is not getting water where it's needed, which is around the dripline of the rosebush.
• Install drip underneath cardboard+mulch Inline drip like Netafim can be installed under c+m. Then there is a problem of how to check if drip is working. 
• Spray - We've tried citrus spray and that does destroy the foliage, but it recovers soon and continues on. And citrus spray is not totally non-toxic to animals. The city has tried whatever they spray (Roundup?) and that is not good for gardeners or for roses. What about vinegar? Pretty much the same story. 
• Whack/mow - Perhaps just to make it look less messy, discourage the flowers, and slow it down? Theoretically if you kept mowing the plants down so they never saw sun and never made bulblets, you could discourage them. If you reduced the sugar-making factories (leaves) the bulblets will be smaller. Small comfort to reduce 20 bulblets to 10 but every bit helps.
• Spray? or No Spray? Read Vinegar: Is it a “Safer” Herbicide? Sprays that only kill leaves is equivalent to whacking them. Vinegar is not without its dangers and think of the wildlife getting concentrated vinegar on their legs and bellies. Neem oil? We may only have known about it being used as an insecticide, but some people use it for weeds, too. Read "Organic Herbicides for Weed Control in Urban Landscapes" from UC IPM. Lots of considerations about time of year, state of growth, whether it works on the roots, bulbs, etc.  
• Pull Pull Pull - around the roses themselves, we can only keep pulling until the plant gives up the ghost. Once you pull, the plant needs to use its resources stored in its bulb. If you continuously knocked it down, how would that affect it? Would it grow fewer bulblets? Would it waste away like that rotting onion in your fridge bin?
• Look at the roses instead - Yes, I go to rose gardens to see what kinds of weed nightmares other gardens have, like Bermuda grass. But your casual visitor will be looking at the roses and sunshine. If they say something about the weeds, you can tell them which days we volunteer.  
• A neat frame shows care. Make sure that there are no weeks in your path and your bricks are tidy. See how much better that looks?
• Remove the dirt and bring in new dirt. The Morcom rose garden rosarians did this and didn't work. Not sure why. In our case, the seeds are everywhere, coming in from paths.
• Plant something that doesn't need weekly water. The Devil Bulbs spread best to areas that are well watered. We rarely see them in drier areas. Convert to Earth-kind roses and water infrequently? However, our beloved winter rains bring up the seeds. 
• Admire their persistence and their place in plant succession - Weeds are the colonizers of bare ground. And what is our rose garden? Bare ground with roses stuck in there. Weeds are the first colonizers for the succession of bare ground to our original oak grasslands. The weeds make the ground cooler. They capture carbon and create humic acid that releases nutrients in our clay soil and makes the clay friable. Weeds bring up nutrients from below. Eventually, if left to its own devices our garden will become an oak woodland, courtesy of our blue jays who are constantly planting oaks.

Lovely relatives & Latin roots

The Pacific Bulb Society list some relatives that are not invasive and a bright yellow color. And they mention the "Devil Bulb" as something that is sometimes introduced as something else or tags along with another. They recommend tossing the soil of infested pots. Just throw it out.

The Missouri Botantic Garden says "The genus name Nothoscordum comes from the Greek nothos, meaning "illegitimate" and skordo meaning "garlic", in reference to the superficial resemblance of members of this genus to those of the genus Allium which includes garlic and onions." 

References

• Cal-IPC gives it a 16 rating. The rating >16 is "reject". Dispersal is from garden waste and contaminated soil.
• Fragrant False Garlic notes from India
• Calflora - only shows one incidence in Alameda County, in the Bonsai Garden at Lakeside gardens! We know that it is elsewhere in Northern California. Santa Barbara to San Diego counties.
• In Defense of Weeds

So if we look at the "Devil Bulb" as a "Guardian of the Soil", what is it telling us and what is it doing for us? I don't know. I don't have the book, but this looks interesting!

The END

I wish

Our only consolation is that the person who stole a whole rose bush probably has the devil bulb in his or his mother's garden. And possibly the rose curculio beetle.