Cold hardiness & minimum temperature

Is New York Aster 'Fellowship' (Symphyotrichum novi-belgii)cold hardy? Hardiness zone & min temp

Also called New York Aster, Michaelmas Daisy, Starwort.

More about new york aster 'fellowship'

About New York Aster 'Fellowship'

Symphyotrichum novi-belgii · also called New York Aster, Michaelmas Daisy · flowering

A tall, classic Michaelmas daisy bearing large, semi-double soft-pink flowers with golden centres in autumn. 'Fellowship' is one of the most popular tall cultivars, providing excellent late-season colour. Like most asters it requires staking in exposed sites and division every few years. Mildly toxic to dogs and cats.

Cold limit: USDA 4-8 · RHS H7 (-25-28°C)

What new york aster 'fellowship''s hardiness rating actually means

Yes — new york aster 'fellowship' is genuinely cold hardy. Rated RHS H7 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H7 means: Hardy in the severest European continental winters. On the US scale that maps to USDA 4-8 — 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 below about −20 °C. New York Aster 'Fellowship' is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for new york aster 'fellowship' as it gets too cold:

It tolerates winter lows to about −20 °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 new york aster 'fellowship' go outside or overwinter — and where?

Plant it out within USDA 4-8 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 new york aster 'fellowship' can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H7 figure above.

New York Aster 'Fellowship' hardiness — frequently asked questions

Is new york aster 'fellowship' cold hardy?

Yes — new york aster 'fellowship' is genuinely cold hardy. Rated RHS H7 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. New York Aster 'Fellowship' is hardy across USDA 4-8; 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 new york aster 'fellowship' can survive?

Minimum survivable temperature is roughly below about −20 °C. New York Aster 'Fellowship' is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is new york aster 'fellowship'?

New York Aster 'Fellowship' is rated USDA 4-8 and RHS H7 — Hardy in the severest European continental winters.

Can new york aster 'fellowship' survive winter outside?

Plant it out within USDA 4-8 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 new york aster 'fellowship' below its minimum temperature?

It tolerates winter lows to about −20 °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.