They might look innocent sitting in their mesh bags at your local department store or garden center… but some bulbs have a dark side. So much so, in fact, that experts are warning of the invasive bulbs to avoid planting in your garden this fall.
Yes, really. November may have become synonymous with spring bulbs over the years, but that doesn’t mean you should plant them on autopilot. Especially as some of the more thuggish varieties, once established, can take over lawns, woodland edges, and flower beds, pushing out native species and proving nearly impossible to remove.
Whether you’re more fond of classic tulips, then, or tempted by some of the more unusual spring bulbs on offer, here are five bulbs experts warn against planting in your garden, as well as one surprisingly common favorite that deserves a little caution…
1. Star-of-Bethlehem
Star-of-Bethlehem (Ornithogalum umbellatum) is a pretty spring bloomer that has long been dogged by horror stories. Why? Because it reproduces both by seed and underground bulbils, forming dense colonies that crowd out native plants. Or, as the Missouri Department of Conservation warns, because it is “weedy and potentially invasive and should not be planted in the Midwest.”
Once it’s in your soil, this bulb is quick to escape cultivation and notoriously difficult to eradicate; even tiny bulb fragments can regrow like something out of The Day Of The Triffids. So, if you want to play it safe, try an alternative like spring starflower (Ipheion uniflorum) for a charming blue-white bloomer that stays compact and pollinator-friendly.
Shop native and non-invasive spring starflower bulbs via the CZ Grain Store on Amazon.
2. Yellow Flag Iris
Introduced a while back as an ornamental aquatic, yellow flag iris (Iris pseudacorus) has betrayed us all by spreading aggressively through wetlands, lakeshores, and streams. It forms dense mats of rhizomes that choke native wetland vegetation and alter habitats… all of which are, naturally, very bad news.
While its showy yellow blooms may be tempting, consider this one to avoid at all costs. There’s a reason why in many states (including Maryland, Washington, and Oregon) this spring bulb is officially listed as invasive, y'know.
3. Wild Garlic
Looking every bit like an alien plant sent to enslave the human race, wild garlic (Allium vineale) pops up in lawns and pastures across the U.S., producing slender leaves and a strong garlicky scent.
Don’t be fooled by its spot on the allium family tree; every bit as troublesome as wild onions, this invasive spring bulb spreads quickly and is incredibly difficult to dig out once it’s established.
Worse still? This one can actually taint the flavor of milk from grazing livestock; a surefire sign of how pervasive it can be. Avoid, avoid, avoid.
4. Spanish Bluebell
A staple of cottage gardens, Spanish bluebells (Hyacinthoides hispanica) may seem harmless, but they are Trouble with a capital T, happily naturalizing and hybridizing with native bluebells in a plot to outcompete them.
It’s an issue that is famously prevalent in the UK, but fair warning: these beautiful blooms pose just as much a problem here in the U.S. spreading readily in USDA Hardiness Zones where our winters are milder.
Consider this a staunch reminder, then, that even the most beloved ornamental bulbs can behave badly outside their native range. Take care to dig out every single bit lest your garden be completely overrun.
5. Italian Arum
With glossy leaves and bright orange berries, the shade-loving Italian arum (Arum italicum) – also known as Lords and Ladies – is gaining popularity in ornamental borders. However, it spreads by rhizomes and seed, and once it takes hold, it’s extremely hard to remove… so much so that it’s classified as a toxic weed in many areas.
We know, we know; it looks just like the striking calla lily, but this one is poisonous, persistent, and now appearing on invasive watch lists in the Pacific Northwest. A triple threat for gardeners and pets alike, essentially.
Control by digging is most effective for small invasions (we really rate this Stainless Steel Serrated Hand Shovel from Amazon), as is dumping boiling water on the roots at regular intervals.
Wildcard: Grape Hyacinth
We bet you didn’t expect to see the beloved grape hyacinth (Muscari armeniacum / Muscari neglectum) on our list, did you? Surprise!
This tiny spring bulb might be adored for its clusters of blue “grapes,” but it can quietly take over garden borders and lawns. In fact, some U.S. extensions note that it “readily naturalizes and may become invasive in some situations.”
That being said, this one is not a banned plant; just a sneaky spreader. Keep this potentially invasive spring bulb, then, in contained areas or pots if you love its pops of color; something like a bulb trifle should do the trick perfectly!
If this list has taught you anything, let it be this; do your research before planting anything, and always check your state’s invasive plant list through the National Invasive Species Information Center or your local extension service.
Remember, many “problem plants” start out as innocent garden additions, but knowing which invasive spring bulbs to avoid can save you years of backbreaking weeding later.
Good luck, then, and may the odds be ever in your favor...
