Illustration
Red Calla
Zantedeschia 'Garnet Glow'
Red Calla blooms from June through August.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Red Calla
Plant it in part sun. It prefers high water. It is hardy in USDA zones 8–10. Expect it to reach about 24 in tall and 12 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 Red Calla
Red Calla is tender: plant it out after the last frost, once the soil has warmed. In zone 9, the middle of its hardy zones 8 to 10, that means February or March; where spring comes later, it goes out later. Expect flowers from June to August.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 9, the middle of this plant's hardy range, start with zone 9 in February. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Red Calla get?
24 intall5 ft 7 inan adult12 inwideSee Red Calla 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
Red Calla'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.
- devroomen.comDe Vroomen Garden Productsheight, spread, hardiness zones, sun and trait tags
- easytogrowbulbs.comEasy to Grow Bulbsheight, spread, hardiness zones, sun and trait tags
- plants.rogersgardens.comRoger's Gardens (NetPS Plant Finder)height, spread, hardiness zones, sun and trait tags
- Holland Bulb Farmsheight, hardiness zones, sun and trait tags
- Longfield Gardensheight, hardiness zones, sun and trait tags
- costafarms.comCosta Farmsheight, spread and hardiness zones
- dutchbulbs.comDutch Bulbs (Van Bourgondien)height, sun and trait tags
- NC State Extensiongenus Zantedeschiahardiness zones, sun and trait tags
- RHSRoyal Horticultural Societyheight, spread and sun
- greenleafnursery.comGreenleaf Nurseryheight and spread
- kingsgardencenter.comKings Garden Centerheight and sun
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Red Calla
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
Every part is toxic to dogs, cats, horses and people. The calcium oxalate crystals cause intense mouth and throat burning, drooling, swelling and vomiting. per ASPCA and NC State
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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.