Illustration
Ruby Giant
Crocus tommasinianus 'Ruby Giant'
Ruby Giant blooms from February through March.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Ruby Giant
Plant it in full sun. It prefers low water. It is hardy in USDA zones 3–8. Expect it to reach about 4 in tall and 3 in wide at maturity, in roughly 1 year (not yet checked).
What was checked
Mature height and spread, hardiness zones, sun and the trait tags were checked against named botanical sources for this plant. The bloom months and water need on this page were not, and each fact above says which. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.
When to plant Ruby Giant
Ruby Giant is a fall-planted bulb: get it in the ground 6 to 8 weeks before the ground freezes, typically September or October in zone 5, the middle of its hardy zones 3 to 8. It pays you back the following February to March.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 5, the middle of this plant's hardy range, start with zone 5 in September. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Ruby Giant get?
4 intall5 ft 7 inan adult3 inwideSee Ruby Giant in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.
Where these facts come from
Ruby Giant's height, spread, hardiness zones, sun and trait tags were checked against 11 published sources on July 29, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.
- easytogrowbulbs.comEasy to Grow Bulbsheight, spread, hardiness zones, sun and trait tags
- Missouri Botanical GardenPlant Finderheight, spread, hardiness zones and sun
- Breck'sheight, hardiness zones and sun
- Brent and Becky's Bulbsheight, hardiness zones and sun
- colorblends.comColorblends Wholesale Flowerbulbsheight, hardiness zones and sun
- John ScheepersBeauty from Bulbsheight, hardiness zones and sun
- RHSRoyal Horticultural Societyheight, spread and sun
- Van EngelenWholesale Flower Bulbsheight, hardiness zones and sun
- Chicago Botanic GardenPlant Finderhardiness zones and sun
- High Country Gardensheight and hardiness zones
- NC State Extensionspecies pagehardiness zones and sun
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Ruby Giant
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
Only mildly toxic: ingestion causes GI upset (drooling, vomiting, diarrhea) in dogs, cats and horses. Do not confuse it with deadly autumn crocus (Colchicum). per ASPCA
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Design a garden with this
Drop this plant onto a 3D plan, see how it fills in, and watch your whole garden bloom across the year.