Illustration
October Skies
Symphyotrichum oblongifolium 'October Skies'
October Skies blooms from September through October.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing October Skies
Plant it in full sun. It prefers low water. It is hardy in USDA zones 3–8. Expect it to reach about 1.5 ft tall and 2.5 ft wide at maturity, in roughly 2 years (a house reading).
No toxicity note is on file for October Skies. That is not a clearance: check its safety for people and pets before planting.
What was checked
Mature height and spread, hardiness zones, sun, water, bloom months and color and the trait tags were checked against named botanical sources for this plant, with what the sources could not settle written down; years to mature size rests on a recorded house rule where no publisher states one, and is marked so; its common name and alternate names have not been checked yet. Each fact above carries its own mark. 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 October Skies
Plant October Skies 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 5, the middle of its hardy zones 3 to 8, spring means April to June and fall means August or September. Once settled, it blooms from September to October.
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 April. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does October Skies get?
1.5 fttall5 ft 7 inan adult2.5 ftwideSee October Skies 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 October Skies
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space October Skies about 2.5 ft apart, center to center, so each plant has room to reach its full width.
Add October Skies 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
October Skies' height, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases, pests and toxicity were checked against 19 published sources on August 24, 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.
- NC State ExtensionSymphyotrichum oblongifoliumheight, spread, hardiness zones, sun, water, bloom months and color, years to mature size, trait tags, soil, diseases and pests
- Missouri Botanical GardenSymphyotrichum oblongifolium 'October Skies'height, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil and diseases
- Mt. Cuba CenterOctober Skies Aromatic Asterheight, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil and pests
- New Moon NurseryAster oblongifolius 'October Skies'height, spread, hardiness zones, sun, water, bloom months and color, years to mature size, trait tags and pests
- usperennials.comUS Perennials (Aster oblongifolius 'October Skies')height, spread, hardiness zones, sun, water, bloom months and color, trait tags, pests and toxicity
- Chicago Botanic GardenSymphyotrichum oblongifolium 'October Skies'height, hardiness zones, sun, bloom months and color, trait tags, diseases and pests
- Prairie Moon NurserySymphyotrichum oblongifolium, Aromatic Asterheight, hardiness zones, sun, water, bloom months and color, trait tags and soil
- RHSRoyal Horticultural Societyheight, spread, sun, water, bloom months and color, trait tags and soil
- Fine Gardeningheight, hardiness zones, sun, bloom months and color, soil and diseases
- luriegarden.orgLurie Garden, Millennium Park, Chicagoheight, spread, hardiness zones, sun and bloom months and color
- kb.jniplants.comJohnson's Nursery Knowledge Basehardiness zones, water, soil, pests and toxicity
- Lady Bird Johnson Wildflower Centersun, water, bloom months and color and soil
- Missouri Botanical GardenSymphyotrichum oblongifoliumheight, spread, hardiness zones, sun and trait tags
- Missouri Department of ConservationField Guideheight, bloom months and color, pests and toxicity
- Missouri Botanical GardenPlant Finderhardiness zones and diseases
- arboretum.wisc.eduUniversity of Wisconsin-Madison Arboretumheight
- Chicago Botanic GardenSmart Gardenerheight
- Mt. Cuba CenterTrial Gardensoil
- NC State ExtensionPlant Toolboxtoxicity
How the checking works, and what each standard covers, is on the verified plants page.
Featured in these guides
Explore similar plants
You might also like
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.