Cold hardiness & minimum temperature

Is Illinois Tick Trefoil (Desmodium illinoense)cold hardy? Hardiness zone & min temp

Also called Illinois tick trefoil, Illinois tick clover, Prairie tick trefoil.

More about illinois tick trefoil

About Illinois Tick Trefoil

Desmodium illinoense · also called Illinois tick trefoil, Illinois tick clover · flowering

Desmodium illinoense is a native perennial forb of dry to mesic tallgrass prairies and open woodlands in the central United States, ranging from Ohio west to Nebraska and south to Texas. It bears loosely branched racemes of small pink to lavender pea-like flowers in mid-summer, forming a valuable wildlife plant — the foliage is a larval host for several hairstreak butterfly species and the flowers are visited by native bees. It is better adapted to drier, sandier soils than Desmodium canadense and is more tolerant of drought. It is not listed as toxic to cats or dogs by the ASPCA.

Cold limit: USDA 4-8 · RHS H6 (-30°C to 40°C)

What illinois tick trefoil's hardiness rating actually means

Yes — illinois tick trefoil is genuinely cold hardy. Rated RHS H6 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. Its RHS rating of H6 means: Hardy throughout the UK and northern Europe. 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 about −20 to −15 °C. Illinois Tick Trefoil is built for winter — once established it takes hard frost and snow in its stride.

Concretely, for illinois tick trefoil as it gets too cold:

It tolerates winter lows to about −20 to −15 °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 illinois tick trefoil 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 illinois tick trefoil can be outside. US growers can check USDA zones; UK growers should use the RHS hardiness ratings, which match the H6 figure above.

Illinois Tick Trefoil hardiness — frequently asked questions

Is illinois tick trefoil cold hardy?

Yes — illinois tick trefoil is genuinely cold hardy. Rated RHS H6 and USDA 4-8, it lives outdoors all year and needs winter cold rather than protection from it. An outdoor plant. Illinois Tick Trefoil 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 illinois tick trefoil can survive?

Minimum survivable temperature is roughly about −20 to −15 °C. Illinois Tick Trefoil is built for winter — once established it takes hard frost and snow in its stride.

What hardiness zone is illinois tick trefoil?

Illinois Tick Trefoil is rated USDA 4-8 and RHS H6 — Hardy throughout the UK and northern Europe.

Can illinois tick trefoil 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 illinois tick trefoil below its minimum temperature?

It tolerates winter lows to about −20 to −15 °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.