The Althea Tree in Texas

August in Texas.  It’s so hot roses won’t bloom, the don’t when it’s 100 degrees every day.  Perennials are going to seed.  We are all exhausted with the hot weather but the Althea steps up to the plate and shines.  I call the Althea tree my miracle bloomer!  And it’s not a puny bloomer!  It’s prolific.

Altheas have been around for a long time in Texas.  You see them at old homesteads at least a 100 years old.  Of course, those are the single petal purple, which are beautiful to me.  There are certainly fancier ones now.  A colors are splendid.

I believe Altheas are not used more is because they do not draw attention until August and by then everyone knows that is the worst time to plant anything.

Growth Habit and Bloom Time

• Growth Habit: Altheas are upright, deciduous shrubs or small trees, typically reaching 8–12 feet in height with a spread of 4–10 feet. They can be pruned into tree forms or maintained as dense shrubs.

• Bloom Time: These plants bloom profusely from late spring through fall, often continuing into the hottest months when other plants wane. ​

Flower Forms and Colors

• Single Blooms: Feature a classic hibiscus-like appearance with a prominent central stamen.​

• Double Blooms: Exhibit ruffled, carnation-like petals, offering a fuller look. Varieties like ‘Jimmy’s Double Pink’ are known for their abundant, double pink flowers. ​

• Color Range: Altheas come in a spectrum of colors, including white, pink, red, purple, blue, and lavender, depending on the cultivar.

Notable Cultivars and Awards

• Blue Angel and White Angel: These cultivars have been designated as Texas Superstars by Texas A&M AgriLife for their exceptional performance in Texas landscapes. ‘Blue Angel’ boasts vibrant blue, trumpet-shaped flowers, while ‘White Angel’ offers crisp white blooms. Both are known for their extended blooming seasons and adaptability. ​

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Althea at the Dallas Arboretum

The Dallas Arboretum showcases Althea varieties in several of its gardens, notably:​

• Poetry Garden: Features ‘Fireworks’ Double Altheas lining the pathways, providing a stunning display of magenta blooms from June through autumn. ​

These plantings highlight Althea’s ornamental value and its suitability for formal garden settings.

Fireworks is a Double Althea that comes in white, purple and magenta.

Altheas as Trees

Growing Tips for Texas Gardeners

• Sunlight: Plant in full sun to ensure maximum blooming potential.​

• Soil: Prefers well-drained soil; moderately drought-tolerant once established.​

• Pruning: Prune in late winter or early spring to promote vigorous new growth and abundant flowering, as Altheas bloom on new wood.

• Maintenance: Generally low-maintenance; however, ensure good air circulation to prevent fungal issues.

Q: Is Althea (Rose of Sharon) a good plant for Texas gardens?
A: Yes. Althea is heat-tolerant, drought-resistant once established, and thrives in the Texas climate. It performs especially well in full sun and tolerates urban soils.

Q: When does Althea bloom in Texas?
A: Althea typically blooms from late spring through early fall. It is one of the few large-flowering shrubs that continues blooming during the hottest months.

Q: What colors and flower types are available?
A: Althea comes in a wide range of colors—white, lavender, purple, pink, red, and blue—and flower forms include single and double blooms. Cultivars like ‘Blue Angel’ and ‘White Angel’ are known for their vibrant color and performance.

Q: Can Althea be grown as a standard (tree form)?
A: Yes. Althea can be pruned and shaped into a single-trunk standard or multi-stemmed small tree. This makes it useful for formal gardens or tight spaces where upright growth is needed.

Q: Are there any award-winning varieties for Texas?
A: Yes. ‘Blue Angel’ and ‘White Angel’ are Texas Superstar selections—recognized by Texas A&M AgriLife for their resilience, extended bloom time, and ornamental value.