A pretty little menace
They’re a beautiful sight and can be seen each spring when they turn a green-lawn blue for a week or so, usually in April. But is that a good thing? The flower responsible for this transformation is scilla, sometimes called squill, and confusion exists because it could be due to two different plants. The difference isn’t obvious because the small flowers are usually admired from a distance, otherwise you might have to flop down on your knees for a closer look. Both plants have similar straplike leaves and grow from bulbs, reaching only 10 to 20 centimetres tall.
The blue flowers that you might have seen on your morning walk are most likely either Scilla siberica or a species of chionodoxa, except to cause confusion, chionodoxa has been reassigned as a section now within the scilla genus, so scilla they are. There are many different species in each genus, but the common ones here are the deep blue Scilla siberica or Chionodoxa luciliae, which can also be pink or white. Even the Royal Horticultural Society states there is some debate over which species are commonly grown in gardens, at least in the U.K., where it has naturalized at the expense of other plants. Even so, the RHS has given three species of scilla their prestigious Award of Garden Merit.
Botanical nomenclature aside, I’ll refer to them here on under the original names or we’ll all get confused. First, Scilla siberica which, despite the name, did not originate in Siberia, but southwestern Russia, across the Caucasus and over to Türkiye, the new official name for Turkey — more confusion. Chionodoxa originated further south than scilla, on the islands of the eastern Mediterranean and over to Türkiye.
Scilla siberica is the one with only a few dark blue flowers on each stem. They droop similar to English bluebells, but in full sun the flowers sometimes turn slightly upwards. If you do get down on your knees for a closer look, you’ll spot a key difference between the two. The anthers on scilla are almost black and protrude a little beyond the blue petals, while the anthers on the upward facing, star-shaped flowers of Chionodoxa luciliae are compact and white. Chionodoxa also produces more flowers on each stem, up to 16, though the plant itself is a little stunted compared to scilla. The typical flowers are a paler blue with a white centre, but there are also varieties in pink or white.
Both species were introduced to North America as ornamental garden plants, popular because they’re cold-resistant and they flower early, in some areas as soon as the snow leaves, hence one of the common names for chionodoxa, glory of the snow. They all sprout up in full sun before the trees leaf out, then go dormant for the rest of the year.
When planted in a lawn they vanish with the first mowing. Even in that blue lawn you spotted, a colony might have begun with a few bulbs, planted like crocus, but these plants self-seed profusely and will carpet a lawn and spread into a flower bed or even a roadside given the chance. Mowing as soon as the flowers fade will prevent the seeds from spreading elsewhere, where the plants can become a problem.
That blue carpet of a spring lawn might be the desired effect, but it’s not a valued trait as scilla will also spread into woodland and take over the understory of a forest, impeding the growth of native ephemerals by engulfing them with dense foliage. Pretty they may be, scilla are considered an invasive species in Ontario and they’re toxic to some animals.