Salicicola Articles

Sheep's Bit (Jasione montana):
A New Invasive?

Irina Kadis
Jasione montana
Jasione montana
Sheep's bit (Jasione montana) has been introduced as an ornamental both to eastern and western North American costal states. This European annual or biennial is naturally distributed all over Europe—from Northern Ireland to Greece and all the way from Britain to European Russia an even farther, to the very Urals Mountain Range, the landmark separating Europe from Asia. A plant of dry sandy and rocky habitats with poor soil, Jasione montana occurs in open sandy woods, on dry rocks, or simply on pure sand both inland and on the coast.
The inflorescence of this attractive plant is a dense head composed of tiny blue florets, which is quite unusual in the bluebell family (Campanulaceae), where it belongs, hence it is often mistakenly taken for a teasel (Dipsacaceae) family member—something like scabious (Knautia). A closer inspection of each tiny campanulate floret, however, helps attribute the plant properly.
Lured by the innocent appearance and unsophisticated growing requirements of sheep's bit, gardeners keep reintroducing it to North America. Profit-minded nursery dealers find it easy to collect the abundant seed and thus satisfy the growing demand, which they stimulate by on-line advertising.
In fact the plant is already well established in southeastern Massachusetts. It has become alarmingly abundant along highways 495, and 128, where the roadside is continuous open mowed lawn. During the flowering time (July/August), one can drive miles and miles along the blue stripe of sheep's bit in this area. You can find large infestations not only on roadsides, but also in any dry sandy disturbed habitat, for example, under the powerlines crossing Myles Standish State Forest and all around, on the perimeter of that park. A threat from this invader for Myles Standish State Forest, a unique pitch-pine barrens community in eastern MA, is now imminent.
From the sandy southeast Jasione montana is actively spreading to inland MA. This year it has become very conspicuous along small roads in Randolph/Braintree area reaching west to Newton along Rt. 128/95. North of Boston so far it is not that prominent.
By the time sheep's bit will be claimed invasive and banned from all sales, the fight will be already lost, as it happened multiple times with other invasives introduced as ornamentals. Once Sheep's bit finds its way to Rocky Mountain States, it must be disastrous.

Irina Kadis
9 Aug 2009

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