Cold hardiness & minimum temperature

Is Yellow Bladderwort (Utricularia vulgaris)cold hardy? Hardiness zone & min temp

Also called greater bladderwort, common bladderwort.

More about yellow bladderwort

About Yellow Bladderwort

Utricularia vulgaris · also called greater bladderwort, common bladderwort · houseplant

Utricularia vulgaris, the greater bladderwort, is a rootless aquatic carnivorous plant that floats in still, acidic water. Its feathery submerged stems carry hundreds of tiny suction-trap bladders that snap shut on water fleas and mosquito larvae in milliseconds. In summer it lifts bright yellow snapdragon-like flowers above the surface, making it a striking pond or water-bowl carnivore.

Cold limit: USDA 4-9 (a hardy temperate species; overwinters as turions) · RHS H5 (15-28°C summer; cool dormancy near 0-10°C in winter)

Watch for — Disappears in winter: Normal — it forms sinking turions and dies back, then regrows in spring. Leave the vessel undisturbed and cool over winter.

What yellow bladderwort's hardiness rating actually means

Yes — yellow bladderwort is genuinely cold hardy. Rated RHS H5 and USDA 4-9 (a hardy temperate species; overwinters as turions), it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H5 means: Hardy in most of the UK and in cold winters. On the US scale that maps to USDA 4-9 (a hardy temperate species; overwinters as turions) — the zones where it can be left outdoors year-round.

New to these scales? The USDA hardiness zone map explained covers how the zone numbers work, and you can find your own zone with the zone finder.

Minimum temperature — and what happens below it

Minimum survivable temperature is roughly about −15 to −10 °C. Yellow Bladderwort is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for yellow bladderwort as it gets too cold:

It tolerates winter lows to about −15 to −10 °C once established.
Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root.
First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.

Can yellow bladderwort go outside or overwinter — and where?

Plant it out within USDA 4-9 (a hardy temperate species; overwinters as turions) and it overwinters with little or no help.
It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy.
The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

Work back from your local frost dates with the frost-date calculator: the last spring frost and first autumn frost are what really decide when yellow bladderwort can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Yellow Bladderwort hardiness — frequently asked questions

Is yellow bladderwort cold hardy?

Yes — yellow bladderwort is genuinely cold hardy. Rated RHS H5 and USDA 4-9 (a hardy temperate species; overwinters as turions), it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Yellow Bladderwort is hardy across USDA 4-9 (a hardy temperate species; overwinters as turions); it belongs in the ground or a frost-proof container, not on a windowsill, and many types actively need a cold winter to perform.

What is the minimum temperature yellow bladderwort can survive?

Minimum survivable temperature is roughly about −15 to −10 °C. Yellow Bladderwort is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is yellow bladderwort?

Yellow Bladderwort is rated USDA 4-9 (a hardy temperate species; overwinters as turions) and RHS H5 — Hardy in most of the UK and in cold winters.

Can yellow bladderwort survive winter outside?

Plant it out within USDA 4-9 (a hardy temperate species; overwinters as turions) and it overwinters with little or no help. It does not want to come indoors — a warm winter room actually weakens a hardy plant by denying it dormancy. The real risks in its range are waterlogging, wind-rock on young plants, and a late hard frost on new growth — not ordinary winter cold.

What happens to yellow bladderwort below its minimum temperature?

It tolerates winter lows to about −15 to −10 °C once established. Below its rated zone, the visible damage is browned or blackened top growth and, in the worst case, a killed crown or root. First-year, newly planted, or container-grown specimens are noticeably less hardy than established garden plants — the roots are exposed.