A friend who attends your webinars (I can’t! I work on Saturdays!) told me about how awful star of Bethlehem bulbs can be and that people plant them without knowing they take over, spread and can kill other plants. How terrible! That’s nightmare stuff. I like bulbs in my garden but until now I’ve stuck with daffodils and tulips. I do peruse the catalogs and sometimes think about buying others. Can you give me a list of which ones I should NOT plant, if there are others like this star of Bethlehem? -B.T. -
Star of Bethlehem or nap-at-noon (Ornithogalum umbellatum) really is a nightmare plant. There are others that spread uncontrollably but no other bulbs that we know that are allelopaths, too – meaning they stunt or kill other species via chemicals they produce and release to the soil. (How-to details for eradicating such bulbs are in the transcript of the Bulbs webinar Q&A. That transcript’s in the works. Watch for it to be posted here: https://gardenatoz.org/about-us/webinars-appearances-calendar/webinar-audience-notes/#Bulbs
We warn people who want only stay-put bulbs to avoid those below. Most are bulbs of small stature that are very early to grow, bloom and go dormant for the year. For instance, woodland anemone (Anemone blanda) is up, bloomed, and gone before mid-May and is so low to the ground that there is never a need to cut back its inch-high foliage. What bugs people about these bulbs is that they spread by seed into bare spaces between other perennials and where lawngrass is thin. For a few weeks in spring as their foliage yellows into dormancy their presence can change the color of a lawn or very low growing groundcover.
We don’t condemn these bulbs, simply warn you what to expect. We plant them, expecting and accepting their waywardness, and mulch over them in spring wherever later-emerging perennials have not already covered the bulbs’ remains.
Group 1 of 3: Offenders many people accept. Small, early species.
Grape hyacinth (Muscari armeniacum). Sterile variety ‘Saffier’ and cousin species M. latifolium are better bets where you want low, early blue without spread.
Snowdrops (Galanthus nivalis)
Squill (Scilla sibirica)
Striped squill or puschkinia (Puschkinia scillioides, literally, the squill-like Puschkinia).
Winter aconite (Eranthis hyemalis)
Woodland anemone (Anemone blanda)
Its flowers are a blue worth having but you then must accept the plant’s super-spreader character. Seeds of squill (Scilla siberica) will grow in the smallest opening between perennials and in thin lawn. A lawn full of squill is charming in bloom but many people cannot abide the two- or three week period of yellow cast the fading bulb foliage brings to the lawn.
Group 2 of 3: Worse and worst offenders
Bluebells (Hyacinthoides species). Called bluebells (English-, Spanish-, woodland-) they are larger and later than the lesser offenders and multiply forcefully. That is, growing clumps of bluebell bulbs can actually squeeze out other plants.
Star of Bethlehem (Ornithogalum umbellatum). As explained above, it leads our never-plant-this list.
Group 3: Others that warrant a cautionary note
Drumstick allium (A. sphaerocephalum) and blue allium (A. caeruleum). We know one species cannot change into another in a garden but in several instances it has seemed to us that drumstick- and blue alliums morphed into wild onion (Allium tricoccum). Probably it just happens that wild onion is able to more easily sneak in when it can hide among another self-sower's foot-tall, thin, onion-y foliage.
At any rate, fighting wild onion is such a chore that we have taken drumstick- and blue allium off of our desirable plant list even though we truly love their look. Now, we simply admire photos and plantings in other people’s gardens of these species’ red-violet egg-shaped blooms and blue globes rising above low growing perennials in June.
Some of the Asiatic lilies can become pests, as can giant allium (Allium giganteum) if the environment suits them. Although this is really no different than what some daylilies and groundcover perennials do, it can gall the gardener more because these bulb plants “hide” for part of every year (they go dormant). That prolongs the battle and makes it tougher to see and remove the unwanted excess.
More about star of Bethlehem in What's Coming Up 34. Download the pdf magazine to read page 8.
Probably! Wish we could live, garden and learn for 1,000 years - and keep reporting. Because we would surely discover new plant uses and abuses every year.
Watch in catalogs for the words "naturalize", "aggressive", "spreads readily". When you see these words, check further in Extension bulletins from .edu sites and .ext sites. Better to know something is questionable and give it a probationary try than to find out one spring that you’ve become the one waving the caution flag to others.
We’re sorry you can’t join us for the live webinars, B.T. We have fun and the feedback says the information is very useful. All subscribers do have the option of viewing the recordings at their leisure. To subscribe: https://gardenatoz.org/about-us/webinars-appearances-calendar/view-webinars-subscribe/#subscribe