Cold hardiness & minimum temperature

Is Silver Shamrock (Oxalis adenophylla)cold hardy? Hardiness zone & min temp

Also called Silver Shamrock, Chilean Oxalis, Pink Oxalis.

More about silver shamrock

About Silver Shamrock

Oxalis adenophylla · also called Silver Shamrock, Chilean Oxalis · flowering

Oxalis adenophylla is a compact, bulbous perennial native to the rocky screes and grasslands of the Chilean and Argentinian Andes, where it experiences cold winters and dry summers. It forms attractive clumps of silvery-grey, fan-shaped leaves made up of up to 22 small leaflets, and bears cup-shaped lilac-pink flowers in late spring. The most important care fact is excellent drainage: the whiskery corms will rot quickly in heavy, waterlogged soil, especially over winter. This plant is toxic to cats and dogs.

Cold limit: USDA 4-9 · RHS H5 (-15 to 20°C)

Watch for — Corm rot: The most common problem; caused by overly wet or poorly drained soil, especially in winter dormancy. Lift and store corms in dry sand if growing in a wet climate.

What silver shamrock's hardiness rating actually means

Yes — silver shamrock is genuinely cold hardy. Rated RHS H5 and USDA 4-9, 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 — 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. Silver Shamrock is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for silver shamrock 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 silver shamrock go outside or overwinter — and where?

Plant it out within USDA 4-9 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 silver shamrock can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H5 figure above.

Silver Shamrock hardiness — frequently asked questions

Is silver shamrock cold hardy?

Yes — silver shamrock is genuinely cold hardy. Rated RHS H5 and USDA 4-9, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Silver Shamrock is hardy across USDA 4-9; 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 silver shamrock can survive?

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

What hardiness zone is silver shamrock?

Silver Shamrock is rated USDA 4-9 and RHS H5 — Hardy in most of the UK and in cold winters.

Can silver shamrock survive winter outside?

Plant it out within USDA 4-9 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 silver shamrock 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.