San Marcos Hibiscus
Gossypium harknessii
A compact, very drought-tolerant shrub with yellow and red summer blooms that attract bees, birds, and butterflies.
Hardy in USDA zones 9-11 and frost-sensitive; foliage burns below the mid-20s, so plant in warm low-desert spots and avoid cold pockets.
AMWUA Notes
A very-low-water Baja native and relative of wild cotton; compact and heat-loving, it blooms all summer with minimal irrigation.
Care Guide
Very drought tolerant; water every 2 weeks in summer to keep it full and blooming, then reduce sharply in winter when it may drop leaves.
Prune to shape and thin in late winter; this large shrub can be limbed up into a small multi-trunk tree and blooms on new growth, so cutting back promotes flowers.
Little fertilizer needed in desert soil.
Watch for whiteflies in heat, a common issue in its cotton family; otherwise low-trouble.
Evergreen in mild winters, dropping leaves in cold; it carries cheery yellow hibiscus-like flowers with red centers from summer into fall on a large frame.
Soil, Feeding & Propagation
Well-drained rocky or sandy soils; tolerates caliche and alkaline pH 7.5-8.5.
Needs well-drained soil.
Low feeder.
From seed or semi-hardwood cuttings.
5 ft
Non-aggressive roots; safe near hardscape and pools.
Placement Tips
- •A compact mounding shrub to about 4 ft tall and 5 ft wide; space 4-5 ft apart in a border or foundation planting.
- •Its cheery yellow hibiscus-like flowers with red centers make a bright filler among boulders and larger shrubs.
- •Low litter and clean habit make it a good pool- and patio-side choice.
- •Plant in full sun; it flowers most heavily with reflected heat.
Features
Best Uses
Ecological Value
Attracts
Wildlife Value
Companion Plants
Quick Stats
Design Styles
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Use this care guide to maintain your San Marcos Hibiscus. Questions about your landscape? Reach out anytime.
Data from 2024 AMWUA “Landscape Plants for the Arizona Desert” guide.
San Marcos Hibiscus — common questions
Answers for low-desert Phoenix conditions, drawn from this plant’s growing data.
How much water does San Marcos Hibiscus need in Phoenix?
San Marcos Hibiscus is a very low-water shrub once established. Very drought tolerant; water every 2 weeks in summer to keep it full and blooming, then reduce sharply in winter when it may drop leaves. A very-low-water Baja native and relative of wild cotton; compact and heat-loving, it blooms all summer with minimal irrigation.
How big does San Marcos Hibiscus get?
Expect roughly 4 ft tall and 5 ft wide at maturity, with a moderate growth rate. Allow about 5 ft of spacing when planting. Non-aggressive roots; safe near hardscape and pools.
Can you plant San Marcos Hibiscus near a pool?
Yes. San Marcos Hibiscus is considered pool-friendly, meaning it stays clean enough around water features and hardscape. Litter is rated low.
Can San Marcos Hibiscus handle Arizona heat and winter frost?
San Marcos Hibiscus is hardy in USDA 9-11 and wants full sun. Hardy in USDA zones 9-11 and frost-sensitive; foliage burns below the mid-20s, so plant in warm low-desert spots and avoid cold pockets. Evergreen in mild winters, dropping leaves in cold; it carries cheery yellow hibiscus-like flowers with red centers from summer into fall on a large frame.
Does San Marcos Hibiscus have thorns?
No. San Marcos Hibiscus is thornless, so it is safe alongside walkways, patios and play areas.
Is San Marcos Hibiscus safe around pets?
San Marcos Hibiscus is listed as pet-friendly in this guide. If your dog is a determined chewer, check any new plant with your vet before planting.
When does San Marcos Hibiscus bloom in Arizona?
San Marcos Hibiscus blooms in summer-fall, with yellow/red flowers. The bloom draws bees, butterflies.
How much maintenance does San Marcos Hibiscus need?
San Marcos Hibiscus is low-maintenance. Leaf, flower and pod litter is rated low. Prune to shape and thin in late winter; this large shrub can be limbed up into a small multi-trunk tree and blooms on new growth, so cutting back promotes flowers.
What kind of soil does San Marcos Hibiscus need?
Well-drained rocky or sandy soils; tolerates caliche and alkaline pH 7.5-8.5. Nutrient needs are low. Little fertilizer needed in desert soil.
Is San Marcos Hibiscus native to Arizona?
No. San Marcos Hibiscus is not an Arizona native; it originates from the Baja California, but it is grown successfully in low-desert landscapes here.