Illustration
Encore Autumn Amethyst
Rhododendron 'Encore Autumn Amethyst'
Encore Autumn Amethyst blooms from April through October.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Encore Autumn Amethyst
Plant it in part shade. It prefers moderate water. It is hardy in USDA zones 6–9. Expect it to reach about 4 ft tall and 4 ft wide at maturity, in roughly 4 years (a house reading).
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 Encore Autumn Amethyst
Plant Encore Autumn Amethyst 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 7, the middle of its hardy zones 6 to 9, spring means March to May and fall means September or October. Once settled, it blooms from April to October.
Month-by-month timing for your zone is on the planting calendar; if you garden near zone 7, the middle of this plant's hardy range, start with zone 7 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.
How big does Encore Autumn Amethyst get?
4 fttall5 ft 7 inan adult4 ftwideSee Encore Autumn Amethyst 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 Encore Autumn Amethyst
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Encore Autumn Amethyst about 4 ft apart, center to center, so each plant has room to reach its full width.
Add Encore Autumn Amethyst 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
Encore Autumn Amethyst's height, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases, pests and toxicity were checked against 17 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 ExtensionPlant Toolbox, Rhododendron Encore Groupheight, spread, hardiness zones, sun, water, bloom months and color, soil, diseases, pests and toxicity
- plants.buyallseasons.comAll Seasons Nursery, Lafayette LA (NetPS Plant Finder)height, spread, hardiness zones, sun, water, bloom months and color, years to mature size, trait tags, soil and pests
- US plant patent (Google Patents)breeder registration, full text via Google Patentsheight, spread, hardiness zones, sun, water, bloom months and color, years to mature size, trait tags, soil and pests
- Missouri Botanical GardenPlant Finder, Rhododendron 'Conlee' AUTUMN AMETHYSTheight, spread, hardiness zones, sun, water, bloom months and color, soil, diseases and pests
- The Tree Centerheight, spread, hardiness zones, sun, water, bloom months and color, years to mature size and soil
- University of Arkansas ExtensionUniversity of Arkansas Cooperative Extension Service, Plant of the Weekheight, spread, hardiness zones, sun, water, bloom months and color, trait tags and soil
- encoreazalea.comEncore Azalea (breeder / introducer, Plant Development Services)height, spread, hardiness zones, sun, water, bloom months and color and trait tags
- kiefernursery.comKiefer Landscaping & Nursery, Durham NCheight, spread, hardiness zones, sun, water, soil, diseases and pests
- Plant Addictsheight, spread, hardiness zones, sun, water, bloom months and color and trait tags
- Sooner Plant Farmheight, spread, hardiness zones, sun, years to mature size, trait tags and diseases
- NC State Extensiongenus pagesun, years to mature size, trait tags, soil, pests and toxicity
- stadlergardencenters.comStadler Nurseriesheight, spread, hardiness zones, sun and bloom months and color
- Pleasant Run NurseryAllentown NJheight, spread, hardiness zones and bloom months and color
- gardencentermarketing.comGarden Center Marketing plant libraryheight, spread and hardiness zones
- greenleafnursery.comGreenleaf Nursery Companyheight, spread and hardiness zones
- Missouri Botanical GardenGardening Help FAQsun, soil and diseases
- ASPCAAnimal Poison Control, Toxic and Non-Toxic Plantstoxicity
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Encore Autumn Amethyst
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note.
Safety
All parts contain grayanotoxins. Toxic to dogs, cats and horses: vomiting, diarrhea, weakness, and in serious cases cardiac failure. Pets and livestock are poisoned more readily than people. 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.