Illustration
Mountain Frost Ruby
Dianthus 'Mountain Frost Ruby Snow'
Mountain Frost Ruby blooms from May through August.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Mountain Frost Ruby
Plant it in full sun. It prefers low water. It is hardy in USDA zones 3–9. Expect it to reach about 10 in tall and 12 in wide at maturity, in roughly 2 years (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 Mountain Frost Ruby
Plant Mountain Frost Ruby in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 6, the middle of its hardy zones 3 to 9, spring means March to May and fall means August or September. Once settled, it blooms from May to August.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 6, the middle of this plant's hardy range, start with zone 6 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Mountain Frost Ruby get?
10 intall5 ft 7 inan adult12 inwideSee Mountain Frost Ruby in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.
How far apart to plant Mountain Frost Ruby
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Mountain Frost Ruby about 12 in apart, center to center, so each plant has room to reach its full width.
Add Mountain Frost Ruby to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.
Where these facts come from
Mountain Frost Ruby's height, spread, hardiness zones, sun and trait tags were checked against 17 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.
- bloomables.comBloomables (Star Roses and Plants consumer brand)height, spread, hardiness zones, sun and trait tags
- blueskynursery.caBlue Sky Nursery (Lincoln, Ontario)height, spread, hardiness zones, sun and trait tags
- darwinperennials.comDarwin Perennials (Ball Horticultural, North American introducer)height, spread, hardiness zones, sun and trait tags
- info.ballseed.comBall Seed Plant Informationheight, spread, hardiness zones, sun and trait tags
- laddsgardencenter.comLadd's Garden Center (South Windham, Connecticut)height, spread, hardiness zones, sun and trait tags
- bachmanswholesale.comBachman's Wholesale Nurseryheight, spread, hardiness zones and trait tags
- loghouseplants.comLog House Plants (Cottage Grove, Oregon)height, spread, sun and trait tags
- servescape.comServeScape (Atlanta, Georgia)spread, hardiness zones, sun and trait tags
- gardencentermarketing.comGarden Center Marketing plant databaseheight, spread and hardiness zones
- proctorsnursery.co.ukProctors Nursery (Wiltshire, England)height, spread and sun
- siteone.comSiteOne Landscape Supplyheight, spread and hardiness zones
- succulentspot.comThe Succulent Spotspread, hardiness zones and sun
- agsci.psu.eduPenn State Flower Trials (2021)height and spread
- agsci.psu.eduPenn State Flower Trials (2020)height and spread
- app.lsuagcenter.comLSU AgCenter Hammond Research Station trialssun and trait tags
- goodegreenhouses.comGoode Greenhouses (Des Moines, Iowa)height and sun
- blogs.extension.msstate.eduMississippi State University Extension, Truck Crops Trial Garden (2021)sun
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Mountain Frost Ruby
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
Mildly toxic to dogs and cats: an unknown irritant causes mild stomach upset, and the leaves' saponins can cause mild skin dermatitis in sensitive people. 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.