perennial flower
Black Adder agastache
Needs sharp drainage and full sun, especially in winter-wet climates.
Growing Profile
- Hardiness
- Zones 6a-9a
- Sun
- Full
- Soil
- LoamSandy
- Water
- Low
- Planting depth
- Set the crown at the same level it grew in the nursery pot.
- Container min
- 2+ gal (good)
- Goals
- Pollinators & wildlifeCurb appeal & color
Harvest & Use
- Window
- blue-purple flower spikes in summer
- Output
- 3-8 weeks of bloom/display/year
- First output
- 1-2 yrs
- Best for
- Pollinators & wildlifeCurb appeal & color
Timing: blue-purple flower spikes in summer. This profile tracks 3-8 weeks of bloom/display/year with a harvest or display window of 3-8 weeks where defensible.
Plant photos
What it looks like in the garden
Use these photos to compare the plant's leaves, stems, flowers, fruit, and overall habit before you buy or plant.
Photos show a representative plant in the garden. Fruit color, size, and growth habit can vary by cultivar, season, nursery stock, and site.
Photo sources: Chris Light / Wikimedia Commons (CC BY-SA 4.0)
Quantitative Profile
- Full output
- 2-3 yrs
- Mature size
- 1-4 ft H x 1-3 ft W
- Spacing
- 1-3 ft apart
- Planting depth
- Set the crown at the same level it grew in the nursery pot.
- Container min
- 2+ gal (good)
- Productive life
- 3-10 yrs
- Difficulty
- 2/5
- Reliability
- 4/5
- Data quality
- Medium profile, No pound-yield source
Pound return is the stock-style yield metric. These are planning ranges for comparing plants, not guarantees. Cultivar, rootstock, climate, soil, pruning, pest pressure, and wildlife can move actual results.
Planting Checklist
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Right-size container with drainage
Containers / Before plantingUse a container large enough for mature roots, with open drainage holes to prevent root rot.
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Expanding container potting mix
Containers / Before plantingUse a lighter container medium instead of dense garden soil in pots and grow bags.
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Organic mulch
Soil / After plantingHold soil moisture, suppress weeds, moderate soil temperature, and protect shallow roots.
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Hand trowel
Tools / Planting dayPlant starts, herbs, flowers, bulbs, and smaller container plants at the right depth.
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Finished compost
Soil / Bed prepImprove bed structure and organic matter before planting annuals, perennials, shrubs, and trees.
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Watering wand or can
Watering / Planting dayWater new transplants gently without washing soil away from the crown or roots.
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Rabbit or deer protection
Protection / After plantingGuard young edible, native, and ornamental plants until they can tolerate browsing.
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Bypass pruners
Maintenance / First seasonMake clean cuts for harvesting, deadheading, shaping, and light pruning.
Planting Strategy
- Planting depth: Set the crown at the same level it grew in the nursery pot.
- Container minimum: 2+ gal (good). Use 2+ gal per plant, or wider mixed containers with similar water needs.
- Start with one plant when testing fit in a new bed or container.
Risk Factors
- Match the site first: full light, loam, sandy soil, and low water.
- Use 1-3 ft apart as the first spacing model; adjust for hedges, trellises, containers, or local guidance.
- Plan around mature size: 1-4 ft H x 1-3 ft W.
- Local drainage, pests, chill hours, wildlife pressure, and microclimates can change the result.
Related Planning Guides
Comparable Plants
Sources & Methodology
This guide combines hardiness range, light, soil, water, harvest timing, traits, source listings, plant relationships, and quantitative planning metrics. Pairings are screened for practical garden fit.
Quantitative values use extension and botanical-reference ranges where available. For less-studied cultivars, similar crops fill gaps conservatively. Ranges are intentionally broad so the profile stays useful without pretending to be exact.
Quantitative sources: NC State Extension Gardener Plant ToolboxMissouri Botanical Garden Plant FinderK-State Extension Master Gardener Handbook - Herbaceous PlantsUniversity of Maryland Extension - Types of Containers for Growing VegetablesIllinois Extension - Growing Vegetables in Containers
Source listing: Amazon. Search links are not paid placements unless explicitly marked; affiliate listings may earn a commission. Last reviewed: 2026-05-24.