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Planting zones · Houston, Texas

What Planting Zone Is Houston?

Houston is in USDA zone 9a–9b. Gulf Coast humid subtropical climate with about 52 in. of rain a year, so low-water landscaping here means drought-tolerant plants that also handle downpours and humidity. A 32°F freeze occurs in almost every winter at Bush Intercontinental (median last freeze February 13).

  • USDA zone (2023)9a–9b
  • Coldest night (avg.)25 to 30°FZIP 77002
  • Median last frostFeb 1332°F
  • Median first frostDec 932°F
  • Annual precipitation52 inches
  • Frost-free season300 days

Houston hardiness zone by ZIP code

On the 2023 USDA Plant Hardiness Zone Map, the ZIP codes we sampled in Houston fall in zones 9a to 9b; 77002 (zone 9b) has an average annual extreme minimum of 25 to 30°F. Choose perennials, shrubs, and trees rated at least to zone 9.

2023 USDA zone for sampled Houston ZIP codes
ZIPZoneAvg. coldest night
770029b25 to 30°F
770199b25 to 30°F
770849b25 to 30°F
773799b25 to 30°F
774949a20 to 25°F

Not listed? Look up any ZIP code.

Frost dates and when to plant

The median last spring frost (32°F) at Houston Bush Intercontinental Airport is Feb 13 and the median first fall frost is Dec 9, a typical frost-free season of about 300 days.

Plant container perennials and shrubs after the median last frost (Feb 13), or in early fall at least six weeks before the median first frost (Dec 9) so roots can settle in before the ground freezes.

Rainfall and heat in Houston

Average annual precipitation is 52 inches (Houston Bush Intercontinental Airport, 1991–2020), spread across the year with June the wettest month and February the driest.

The average high in August is about 95°F and the average low in January is about 44°F, measured at about 100 ft.

That is why a zone rating alone isn't enough for a xeriscape here: pick plants that are both cold-hardy to zone 9 and rated very low or low water once established.

Low-water plants for Houston

52 plants in our database are hardy to zone 9 and suited to zone 9. Here are 12, driest first, across plant types.

See all zone 9 plants

Frequently asked questions

What planting zone is Houston?

Houston, TX is in USDA hardiness zone 9a–9b on the 2023 USDA Plant Hardiness Zone Map, based on the ZIP codes we sampled (77002: 9b, 77019: 9b, 77084: 9b, 77379: 9b, 77494: 9a). In 77002, the average coldest night of the year is 25 to 30°F.

When is the last frost in Houston?

The median last spring frost (32°F) at Houston Bush Intercontinental Airport is Feb 13 and the median first fall frost is Dec 9, a typical frost-free season of about 300 days.

How much rain does Houston get?

Average annual precipitation is 52 inches (Houston Bush Intercontinental Airport, 1991–2020), spread across the year with June the wettest month and February the driest.

Sources

  1. NOAA NCEI U.S. Climate Normals 1991–2020, Houston Bush Intercontinental Airport (USW00012960). ncei.noaa.gov
  2. USDA ARS 2023 Plant Hardiness Zone Map, by ZIP. planthardiness.ars.usda.gov