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When to Plant Gladiolus in Bexar County, TX

Bexar County, Texas Zone 9a June

June to-do list for Bexar County, Texas

Each item below is timed to Bexar County, Texas's frost dates and soil temperatures. Skip nothing, stress about nothing.

Avg. last frost March 11
Avg. first frost November 17
Soil temp (4") 74°F
Watering Low
Pest pressure High
Daylight 13.9 hrs
  1. Harvest gladiolus as they ripen

    If you can't use it all right away, check the food-preservation section of your planner.

July prep starts now
  • First harvests: gladiolus

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Gladiolus (Gladiolus spp.) produce tall, stately spikes of trumpet-shaped blooms in a rich array of colors, making them one of the most popular cut flowers in the world. Each spike carries 12–20 florets that open in succession from bottom to top over 7–10 days. By planting corms every two weeks from last frost through early summer, gardeners create a continuous succession of fresh blooms from midsummer through fall. Corms multiply each season — a single planting becomes a growing collection over the years. Ideal for back-of- border planting, cutting gardens, and mixed summer containers.

Bexar County, Texas is in USDA Zone 9a. The average last spring frost is March 11 and the first fall frost is November 17, giving you a growing season of approximately 251 days.

At an elevation of 3,197 feet, Bexar County receives approximately 52.1 inches of rainfall annually with predominantly loam soil. Summer highs average 93°F, providing good warmth for Gladiolus during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Gladiolus root diseases.

Bulb Blooms in Summer Pollinator-friendly Good for cutting
Bexar County, TX (Zone 9a) Long season
251 days
Last Spring Frost March 11
251 growing days
First Fall Frost November 17

Bexar County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.8

Drainage

Well Drained

Gladiolus Planting Risk Windows

Early Start (70% safe) ✓ Fits season (4 days to spare)
Transplant: Mar 1 🌸 Bloom: May 10 – Nov 8
Recommended (50%) ✗ May not fit
Transplant: Mar 11 🌸 Bloom: May 20 – Nov 18
Safe Start (90%) ✗ May not fit
Transplant: Apr 7 🌸 Bloom: Jun 16 – Dec 15

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Bexar County

How your county's soil matches Gladiolus's growing requirements.

Soil pH

Your soil pH (6.5–7.8) is more alkaline than Gladiolus prefers (6.0–6.5). Add sulfur or peat moss to lower pH.

Soil Texture

The loam soil in Bexar County is excellent for Gladiolus — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.2%). Annual compost additions will help Gladiolus.

How to Plant Gladiolus

5"
Planting Depth
5"
Between Plants
12"
Between Rows

Succession Planting Gladiolus

4
successive plantings in your 251-day season

Sow every 8 weeks. Last sowing by Aug 09 to harvest before frost.

Gladiolus Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 286 gal / 100 sq ft

Monthly Watering Guide for Gladiolus

Gladiolus needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Gladiolus Needs Rainfall You Supplement Action
Jan 1.4" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 4.3" 3.6" 0.7" 💧 Light watering
Apr 4.3" 5.6" 0" ✅ Rainfall sufficient
May 4.3" 7.5" 0" ✅ Rainfall sufficient
Jun 4.3" 8.2" 0" ✅ Rainfall sufficient
Jul 4.3" 6.3" 0" ✅ Rainfall sufficient
Aug 4.3" 6.3" 0" ✅ Rainfall sufficient
Sep 4.3" 4.9" 0" ✅ Rainfall sufficient
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 4.3" 1.9" 2.4" 🚿 Regular watering
Dec 1.3" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Bexar County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Gladiolus Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Gladiolus needs ~1,679 GDD — county provides 4,957 GDD Excellent fit

Gladiolus Planting Timeline — Bexar County, TX

Gladiolus Planting Calendar

Activity When Date Range
Transplant Outdoors March 11 Mar 11 – Mar 25
Direct Sow March 11 Mar 11 – Apr 1
Bloom May 20 May 20 – Nov 18

Plant 5" deep · 5" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March Transplant Outdoors Direct Sow
April Direct Sow
May Bloom
June Bloom
July Bloom
August Bloom
September Bloom
October Bloom
November Bloom
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

70–100 days

🧪 Soil pH

Needs 6–6.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

251 days in Bexar County

Growing Tips for Gladiolus in Bexar County

Direct sow Gladiolus outdoors after March 11 in Bexar County when soil has warmed and frost danger has passed.

General growing tips

Plant corms 4–6 inches deep, pointed end up, as soon as soil reaches 60°F after last frost. Space 4–6 inches apart; rows 12 inches apart. Stake or grow through a support grid — tall varieties reach 4–5 feet and tip in wind. Begin succession plantings every 2 weeks through early July for continuous bloom. Water deeply once a week; mulch to conserve moisture and suppress weeds. Cut spikes for vases when the lowest floret just begins to open. After first killing frost (in cold zones), dig corms, let dry for 3–4 weeks in a ventilated spot, remove cormels, and store in mesh bags at 35–50°F. In zones 7b–8a, corms sometimes survive mild winters in ground with heavy mulch; in zones 8b+, in-ground overwintering is reliable.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Gladiolus in Bexar County, TX?

Bexar County is in Zone 9a with an average last frost of March 11. Plan your Gladiolus planting based on this frost date — see the calendar above for exact timing.

What planting zone is Bexar County, TX?

Bexar County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 11 and first fall frost is November 17.

🌱

Your Bexar County Garden Planner — Free

A 22-page printable planner built for Bexar County (Zone 9a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Bexar County, TX. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.