Every year, as the reserve’s bluebells come into flower, the Friends do battle against a dreaded invasive alien: Spanish squill. This week Sarah, Alan, Jim and Ian set to in the copse next to the Heritage Orchard, where the squill are threatening our native bluebells.
Native bluebells (Hyacinthoides non-scripta) are dark blue and fragrant, with flowers on just one side of the stem producing that characteristic droop; the stem and the leaves are slim and flexible. The flowers of Spanish squills (Hyacinthoides hispanica) are lighter in colour, often striped, and can be white or pink as well as blue. The whole plant is more upright; the stem and leaves more robust.
The two species are genetically so similar that they cross pollinate, producing a hybrid. Hybrids are usually weaker, less successful than the parent-species, and infertile – but not in this case. The Hyacinthoides hybrid is tough, adaptable and very fertile; it produces more seed than either bluebell or squill and that seed germinates more easily and in a much wider range of conditions.
The Woodland Trust has estimated that one in every six of our bluebell woods has been invaded by Spanish squill and the resulting hybrids are out-competing the bluebells. Climate change is already threatening the delicately balanced environment in which bluebells thrive; the pressure of an alien competitor for that changing environment could be very damaging.
The only remedy is to wait until both species are in flower and then to pull up every Spanish squill and as many hybrids as can be identified. This is backbreaking work that has to be repeated year after year.
Header image: Spanish squill by Steve Daniels (CC BY SA 2.0)
I have lots of spanish squill in my garden and a smaller area of just bluebells. If I keep squill away from the bluebells will that be enough to protect the bluebells?
No, I am afraid not. The bees don’t know the difference between native bluebells and Spanish squill, and will happily carry pollen between the two. What you are assuming to be native bluebell seedlings (it can take them 5 years to flower) could very well be hybrids. Sorry.
I read with interest about the bluebells and Spanish squill. I have a small area of woodland that is carpeted with bluebells. I just thought I would ask in case one of the team would fancy a walk through it and maybe to offer an opinion on how severe the squill/hybrids are here. Absolutely wouldn’t be expecting anyone to pull anything, but I would quite like to know as maybe in the future I can do something about it. They’re not yet at full force but I have attached a photo from last year.
Hi Will, I’ll pass your questions onto Ian Bushell, who has been waging war against Spanish Squill for many years so he will probably be in contact right away.
Yes I would be most interested to have a look at your bit of woodland. Expanding your picture from last year they look good but still worth examining. When they are nearing bloom just contact me – I’m free most of the time.