perennial
Island alum root
Heuchera maxima
Preview: plant data is awaiting horticulturist review. A professional horticulturist hasn't reviewed our plant table yet. Lists still follow fixed rules for zone, sun, pets, deer and invasive status.
Island alum root is an evergreen perennial hardy in zones 8–10. It grows 1–2 ft tall and 1.5–2.5 ft wide, so plant it 2 ft apart. Give it part shade to shade and little water once established. It flowers white and pink in February to April. In a FloraVista list it usually plays the filler role: a flowering plant that fills the middle or front of the bed. It is native to California. Deer usually leave it alone, and it is not listed as toxic to dogs or cats. Our rules leave it out of lists in the Southeast, Florida and the Gulf and Texas and the South-Central states, where summer heat, humidity or mild winters hold it back even inside its zone range.
Facts from our plant table
- Botanical name
- Heuchera maxima
- Plant type
- Perennial, evergreen
- Hardiness zones
- 8 to 10
- Sun
- Part shade (2–4 hours); Shade (under 2 hours)
- Water
- Low
- Soil
- Well-drained soil; tolerates dry shade under oaks once established.
- Mature size
- 1–2 ft tall × 1.5–2.5 ft wide
- Spacing
- 2 ft apart (centre to centre)
- Growth rate
- Medium
- Bloom
- Feb–Apr · white and pink
- Roles in a bed
- Filler
- Styles
- natural, low water
- Deer resistance
- High: deer rarely eat it
- Pets
- Not listed as toxic to dogs or cats. ASPCA lists coral bells (Heuchera) as non-toxic to dogs and cats.
- Native to
- California
- Pot size and price
- 1-gallon pot, typically $12–$22 (specialist nurseries)
- Plant in
- Fall
- First-year watering
- Water every 7–10 days the first dry season; afterwards an occasional summer soak in shade is enough.
- Pruning
- Remove spent flower stalks and dead leaves in late spring.
Sources: ASPCA Toxic and Non-Toxic Plant List (from general knowledge; not re-checked unless verification is web-checked); Missouri Botanical Garden Plant Finder and grower tags; State extension service guidance and USDA PLANTS distribution maps; Rutgers NJAES Landscape Plants Rated by Deer Resistance; Invasive Plant Atlas of the United States and state noxious weed lists; Typical 2026 US garden-centre and big-box retail listings (estimate). Not yet reviewed by a horticulturist.
Good companions
The plants our list engine most often puts in the same bed as Island alum root, across the sun, zone, pet, deer and style combinations it fits.
- Hummingbird sageSalvia spathaceaperennial · zones 8–10
- Bamboo muhlyMuhlenbergia dumosaornamental grass · zones 9–11
- Mexican honeysuckleJusticia spicigeraperennial · zones 9–11
- FirebushHamelia patensshrub · zones 9–11
- ToyonHeteromeles arbutifoliashrub · zones 8–11
- Boston fernNephrolepis exaltatafern · zones 9–11
If you can't find it
Substitutes our engine offers for Island alum root: same role in the bed, passing the same rules. Some of them are flagged toxic to dogs or cats: check the pet note before you swap.
How this page was made
This page was generated from this plant's record in FloraVista's plant table by fixed rules. The companions and substitutes come from the lists our rules engine composes. No named expert has reviewed this page.
Data status: the plant table is awaiting review by a horticulturist. Check each plant with a local nursery or extension office before you buy.
Sources
- Missouri Botanical Garden Plant Finder, state extension services and the USDA PLANTS database (zones, size, sun, water, bloom, native range)
- ASPCA toxic and non-toxic plant lists (dog and cat toxicity)
- Rutgers NJAES and regional extension deer-resistance ratings
- State noxious-weed and invasive-plant lists and the Invasive Plant Atlas of the US
- Typical US garden-centre listings (pot size and price band)
Generated . How FloraVista chooses plants