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When to plant hyacinths in Missoula: 6 September – 12 November

In Missoula, hyacinth: plant from 6 September to about 12 November.

Bulbs are best planted early in the window: late-planted bulbs may flower later or less well. Late planting works only while the soil can be dug. Mulch after planting.

The date is about two weeks before the average daily temperature here falls below 0 °C (ten years of weather): an estimate, not the day the ground freezes, and a cold spell can freeze it earlier. Sources: Iowa State University Extension, Wisconsin Horticulture Extension, UNH Extension, RHS, how the ground freezes (NRC Canada, CBD-26).

Hyacinth in Missoula: soil, season and weather

Nights then average below 0 °C in November–April; the coldest, February, averages -8.7 °C.

Planting6 September – 12 November
First autumn frost6 October
Coldest nightsFebruary, -8.7 °C
Soil back at 1 °C in spring19 March
Daylight13:06 on 6 September
Daylight at the winter solstice8:32

The same dates in Missoula hold for Garlic, Tulip, Daffodil and Crocus.

Hyacinth in Missoula: depth, winter cold, pests and pets

Plant hyacinths 10 cm deep, at least 7.5 cm apart (RHS). In the ground hyacinths are fully hardy, but in containers they can be frost tender in cold winters (RHS); here winter nights average below 0 °C, so wrap the pots or move them to a sheltered spot.

In Missoula the average daily temperature stays at 10 °C or lower for about 31 weeks a year (our estimate from ten years of monthly weather). For this bulb Wisconsin Horticulture Extension gives a cold period of 12–15 weeks at about 2–10 °C. The winter here gives that in the ground, so the bulbs need no pre-chilling.

Flowers get smaller in the years after planting: for full spikes, replace the bulbs or add a few new ones each autumn (RHS).

If squirrels are a problem, protect the bulbs with wire mesh (RHS). Hyacinths are toxic to dogs, cats and horses: intense vomiting and diarrhoea (ASPCA).

Sources: RHS, Wisconsin Horticulture Extension, ASPCA.

Hyacinth in nearby cities

Around Missoula, Calgary is 5 days earlier and Boise 21 days later.

CityDistanceDateDifference
Helena155 km3 September – 5 November3 days earlier
Spokane271 km15 September – 23 November9 days later
Boise400 km27 September – end of December21 days later
Idaho Falls406 km14 September – 14 November8 days later
Billings441 km14 September – 23 November8 days later
Calgary465 km1 September – 26 October5 days earlier

Where to buy hyacinth for planting in Missoula

Planting stock goes into the ground from 6 September to about 12 November; buy it before that. Within 15 km of Missoula OpenStreetMap lists 3 garden centres, 1 farm-supply shop, 2 plant nurseries, 2 markets and 6 farm shops (collected 28 October 2026).

Places: © OpenStreetMap contributors, ODbL.

Questions

When to plant hyacinths in Missoula?

In Missoula, hyacinth: plant from 6 September to about 12 November. Bulbs are best planted early in the window: late-planted bulbs may flower later or less well. Late planting works only while the soil can be dug. Mulch after planting.

When is the last spring frost in Missoula?

Last spring frost around 18 May, first autumn frost around 6 October.

Other crops in Missoula, with their dates