UK hardiness
Is Eryngium bourgatii 'Picos Blue' hardy in the UK?
Eryngium bourgatii 'Picos Blue'
More about eryngium bourgatii 'picos blue' in the UK
Eryngium bourgatii 'Picos Blue' and the RHS hardiness rating
Eryngium bourgatii 'Picos Blue' is rated RHS H5 — hardy in a cold winter, meaning it withstands winter minimums of about -15 to -10°C. In practice that means it hardy through most of the UK even in severe winters. The RHS rating describes an absolute minimum temperature, not an average: a single hard frost below its band is what does the damage, so the question is always "what is the coldest night my garden gets?", not "what is a typical winter here?".
This follows the RHS plant hardiness rating system (H1a–H7), the UK standard. For the US growing-zone view, see the eryngium bourgatii 'picos blue' USDA hardiness guide.
Does UK region change it?
UK winters vary far more by locality than by latitude. Mild western and coastal areas (the south-west, Pembrokeshire, western Scotland's coast) and urban heat islands run several degrees warmer than inland frost pockets, valleys, and exposed eastern sites at the same latitude. A plant marginal on its RHS rating often survives in a sheltered town garden but fails 20 miles inland — so judge by your own coldest recorded night and microclimate (a south-facing wall, a courtyard) rather than the regional average.
Overwintering eryngium bourgatii 'picos blue' in the UK
For a borderline-hardy plant, the UK winter killers are not just cold air but cold wet roots and wind. Improve drainage before winter, mulch the root zone, move containers to a sheltered spot or against a warm wall, and use horticultural fleece on hard-frost nights. Established plants in free-draining soil take far more cold than a recently planted one in heavy, wet ground.
Eryngium bourgatii 'Picos Blue' UK hardiness — frequently asked questions
Is eryngium bourgatii 'picos blue' hardy in the UK?
Eryngium bourgatii 'Picos Blue' is rated RHS H5 (hardy in a cold winter, hardy to about -15 to -10°C). It hardy through most of the UK even in severe winters.
Can eryngium bourgatii 'picos blue' stay outside over winter in the UK?
In most of the UK, yes, if your garden's coldest night stays within its RHS H5 band (around -15 to -10°C). In colder inland or northern gardens, give it a sheltered spot, sharp drainage, and fleece on hard-frost nights.
What does RHS H5 mean?
RHS hardiness ratings run H1a (needs a heated glasshouse) to H7 (survives below -20°C). Eryngium bourgatii 'Picos Blue''s rating, H5, means hardy in a cold winter — it tolerates winter minimums of about -15 to -10°C. The rating is an absolute minimum, not an average.
How do I overwinter eryngium bourgatii 'picos blue' in the UK?
For a borderline-hardy plant, the UK winter killers are not just cold air but cold wet roots and wind. Improve drainage before winter, mulch the root zone, move containers to a sheltered spot or against a warm wall, and use horticultural fleece on hard-frost nights. Established plants in free-draining soil take far more cold than a recently planted one in heavy, wet ground.
Does UK region change whether eryngium bourgatii 'picos blue' survives?
UK winters vary far more by locality than by latitude. Mild western and coastal areas (the south-west, Pembrokeshire, western Scotland's coast) and urban heat islands run several degrees warmer than inland frost pockets, valleys, and exposed eastern sites at the same latitude. A plant marginal on its RHS rating often survives in a sheltered town garden but fails 20 miles inland — so judge by your own coldest recorded night and microclimate (a south-facing wall, a courtyard) rather than the regional average.
More eryngium bourgatii 'picos blue' care
See the full eryngium bourgatii 'picos blue' care guide, its temperature & humidity needs, and the US (USDA) hardiness version of this page.