Illustration
Anise Hyssop
Agastache
Also called giant hyssop
Anise Hyssop blooms from July through September.
Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.
Growing Anise Hyssop
Plant it in full sun. It prefers low water. It is hardy in USDA zones 5–9. Expect it to reach about 3 ft tall and 1.5 ft wide at maturity, in roughly 2 years (a house reading).
No toxicity note is on file for Anise Hyssop. 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 Anise Hyssop
Plant Anise Hyssop 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 5 to 9, spring means March to May and fall means September or October. Once settled, it blooms from July to September.
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 Anise Hyssop get?
3 fttall5 ft 7 inan adult1.5 ftwideSee Anise Hyssop 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 Anise Hyssop
Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.
Space Anise Hyssop about 1.5 ft apart, center to center, so each plant has room to reach its full width.
Add Anise Hyssop 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
Anise Hyssop's height, spread, hardiness zones, sun, water, bloom months and color, trait tags, soil, diseases, pests and toxicity were checked against 18 published sources on August 21, 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.
- University of Wisconsin HorticultureWisconsin Horticulture, Division of Extension (Anise hyssop, Agastache...height, spread, hardiness zones, sun, water, bloom months and color, years to mature size, trait tags, diseases, pests and toxicity
- Missouri Botanical GardenPlant Finderheight, spread, hardiness zones, sun, water, bloom months and color, soil, diseases, pests and toxicity
- NC State ExtensionAgastacheheight, hardiness zones, sun, water, years to mature size, trait tags, soil, pests and toxicity
- NC State ExtensionAgastache foeniculumheight, spread, hardiness zones, sun, years to mature size, trait tags and toxicity
- University of Illinois ExtensionIllinois Extension, Prairies to Perennials (Agastache, hummingbird mint)height, spread, sun, bloom months and color, trait tags and pests
- Missouri Botanical GardenAgastache nepetoidesheight, spread, hardiness zones, sun, years to mature size and trait tags
- Chicago Botanic GardenAgastache foeniculumheight, spread, hardiness zones, sun and trait tags
- Clemson Home and Garden Information CenterAnise Hyssopheight, spread, hardiness zones, sun and trait tags
- illinoispollinators.orgIllinois Pollinators, University of Illinois Extensionspread, water, bloom months and color and diseases
- Missouri Botanical GardenAgastache foeniculumheight, spread, hardiness zones, sun and trait tags
- Missouri Botanical GardenAgastache canaheight, spread, hardiness zones, sun and trait tags
- Missouri Botanical GardenAgastache rupestrisheight, spread, hardiness zones, sun and trait tags
- Missouri Botanical GardenAgastache rugosa 'Golden Jubilee'height, spread, hardiness zones, sun and trait tags
- Prairie Moon NurseryAgastache foeniculum, Anise Hyssopheight, hardiness zones, sun, years to mature size and trait tags
- High Country Gardenssun, water, soil and diseases
- Lady Bird Johnson Wildflower CenterAgastache foeniculumheight, sun and trait tags
- RHSRoyal Horticultural Society (Agastache)sun and trait tags
- Fine GardeningIssue 228, by Richard Hawke, Chicago Botanic Gardenhardiness zones
How the checking works, and what each standard covers, is on the verified plants page.
Good to know about Anise Hyssop
Curated from university extensions, botanic gardens and other primary sources, with the source named on every note. A note reports what its source says; where that differs from a fact above, the fact above is this entry's stored value, and its mark says whether it has been checked.
Worth knowing
Sharp drainage fixes two problems at once: the same wet, low-oxygen soil that rots the crown is also what kills the plant over winter. per NC State and Wisconsin
Cold-hardiness depends on type
The prairie species is hardy to about zone 3 or 4; hybrids and hummingbird mints center on zones 5 to 9 or 10. Identify yours first. per NC State
Rabbit resistance is disputed
NC State lists it as rabbit-resistant, but Wisconsin says rabbits will eat it. Deer always leave it alone; protect young plants where rabbit pressure is high. per NC State and Wisconsin
Top pollinator plant
A magnet for bees, butterflies and hummingbirds, and a historic honey plant. The straight species and sterile 'Blue Fortune' feed pollinators well; 'Golden Jubilee' is ignored by bees. per NC State and Xerces
Self-sows but stays put
The straight species self-sows freely but spreads only slowly by short rhizomes, so it never runs like true mint. Sterile 'Blue Fortune' barely self-seeds at all. per NC State
Scent that repels deer
The anise-scented oils in the leaves do double duty: they flavor teas, jellies and seasonings, and they make the foliage unpalatable to browsing deer. per NC State and Clemson
Powdery mildew in shade
In humid, shady or crowded spots it gets powdery mildew, leaf spot and rust, usually cosmetic. Full sun and generous spacing for air flow prevent most of it. per NC State and Clemson
What pairs well with Anise Hyssop
Good companions share its growing conditions and add something it lacks: an earlier or later bloom, a lower carpet in front, or structure through winter.
False Indigo
Shares full sun and low water; blooms in late spring, before this one opens; both are strong pollinator plants, and they feed in different months; its seed heads stand through winter, for structure and the birds.
Sea Thrift
Shares full sun and low water; blooms in mid spring, before this one opens; both offer pollinator forage, in different months; evergreen, so the bed keeps its shape through winter.
Rock Cress
Shares full sun and low water; blooms in mid spring, before this one opens; both offer pollinator forage, in different months; evergreen, so the bed keeps its shape through winter.
Sage
Shares full sun and low water; blooms in late spring, before this one opens; both are strong pollinator plants, and they feed in different months; echoes the purple.
Ninebark
Shares full sun and low to moderate water; blooms in late spring, before this one opens; both are strong pollinator plants, and they feed in different months; taller at 6.5 ft, for the layer behind it.
Chives
Shares full sun and low to moderate water; blooms in late spring, before this one opens; both are strong pollinator plants, and they feed in different months; both are North American natives.
Lavender
Shares full sun and low water; opens in early summer and overlaps into this one's season; both are strong pollinator plants; evergreen, so the bed keeps its shape through winter.
Weigela
Shares full sun and low to moderate water; blooms in late spring, before this one opens; both are strong pollinator plants, and they feed in different months; taller at 5 ft, for the layer behind it.
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