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When to Plant Sweet Alyssum in Refugio County, TX

Refugio County, Texas Zone 9b June

Your June planting checklist for Refugio County, Texas

Your garden in Refugio County, Texas is working on a schedule, even when you're not. Here's where you should be this June.

Avg. last frost February 16
Avg. first frost December 6
Soil temp (4") 87°F
Watering Low
Pest pressure High
Daylight 13.8 hrs

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Sweet Alyssum (Lobularia maritima) is a low-growing cool-season annual prized for its honey-scented clusters of tiny white, pink, or purple flowers. A workhorse border plant, it tolerates light frost, self-seeds readily, and attracts beneficial insects throughout its bloom season. In warm climates it often re-blooms in fall after summer heat fades.

Refugio County, Texas is in USDA Zone 9b. The average last spring frost is February 16 and the first fall frost is December 6, giving you a growing season of approximately 293 days.

At an elevation of 1,000 feet, Refugio County receives approximately 68.4 inches of rainfall annually with predominantly loam soil. Summer highs average 103°F, so Sweet Alyssum may need afternoon shade and extra watering during peak heat. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sweet Alyssum root diseases.

Annual Blooms in Spring Pollinator-friendly Deer-resistant Fragrant
Refugio County, TX (Zone 9b) Year-round
293 days
Last Spring Frost February 16
293 growing days
First Fall Frost December 6

Refugio County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.2

Drainage

Well Drained

Sweet Alyssum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (209 days to spare)
Transplant: Dec 29 🌸 Bloom: Feb 2 – May 4
Recommended (50%) ✓ Fits season (202 days to spare)
Transplant: Jan 12 🌸 Bloom: Feb 16 – May 18
Safe Start (90%) ✓ Fits season (194 days to spare)
Transplant: Feb 5 🌸 Bloom: Mar 12 – Jun 11

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 Refugio County

How your county's soil matches Sweet Alyssum's growing requirements.

Soil pH

Your soil pH (6.7–7.2) is within Sweet Alyssum's preferred range (6.0–7.5).

Soil Texture

The loam soil in Refugio County is excellent for Sweet Alyssum — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (2.0%). Annual compost additions will help Sweet Alyssum.

How to Plant Sweet Alyssum

6"
Between Plants
8"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Succession Planting Sweet Alyssum

7
successive plantings in your 293-day season

Sow every 5.1 weeks. Last sowing by Oct 07 to harvest before frost.

For a dedicated fall crop, sow by Sep 27.

Sweet Alyssum Water Budget

Plant needs
0.5″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Sweet Alyssum

Sweet Alyssum needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Sweet Alyssum Needs Rainfall You Supplement Action
Jan 2" 0" ❄️ Dormant
Feb 2.2" 2.1" 0.1" 💧 Light watering
Mar 2.2" 3.9" 0" ✅ Rainfall sufficient
Apr 2.2" 8.3" 0" ✅ Rainfall sufficient
May 2.2" 9.2" 0" ✅ Rainfall sufficient
Jun 2.2" 11.3" 0" ✅ Rainfall sufficient
Jul 2.2" 9.3" 0" ✅ Rainfall sufficient
Aug 2.2" 8" 0" ✅ Rainfall sufficient
Sep 2.2" 5.7" 0" ✅ Rainfall sufficient
Oct 2.2" 4.5" 0" ✅ Rainfall sufficient
Nov 2.2" 2.4" 0" ✅ Rainfall sufficient
Dec 2.2" 1.8" 0.4" 💧 Light watering

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

Sweet Alyssum 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.

Sweet Alyssum needs ~1,431 GDD — county provides 8,011 GDD Excellent fit

Sweet Alyssum Planting Timeline — Refugio County, TX

Sweet Alyssum Planting Calendar

Activity When Date Range
Transplant Outdoors January 12 Jan 12 – Jan 26
Direct Sow December 15 Dec 15 – Jan 5
Bloom February 16 Feb 16 – May 18
Fall Sowing September 27 Sep 27 – Oct 11

· 6" apart · Rows 8" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

45–60 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

293 days in Refugio County

Growing Tips for Sweet Alyssum in Refugio County

Direct sow Sweet Alyssum outdoors after February 16 in Refugio County when soil has warmed and frost danger has passed.

With summer highs reaching 103°F in Refugio County, provide afternoon shade for Sweet Alyssum and water deeply in the morning.

Your generous 294.0-day season in Refugio County allows multiple plantings of Sweet Alyssum. Sow every 22.0 days for continuous harvest.

Common pests for Sweet Alyssum in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Surface-sow seeds — they need light to germinate. Direct-sow as soon as soil can be worked in spring; in zones 7+ also sow in fall. Thin to 6 inches apart. Shear back hard in midsummer when heat causes dormancy — plants recover and re-bloom when cool weather returns. Self-seeds prolifically; allow a few plants to set seed for a perpetual colony.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Alyssum in Refugio County, TX?

Refugio County is in Zone 9b with an average last frost of February 16. Plan your Sweet Alyssum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Refugio County, TX?

Refugio County, Texas is in USDA Hardiness Zone 9b. The average last spring frost is February 16 and first fall frost is December 6.

🌱

Your Refugio County Garden Planner — Free

A 22-page printable planner built for Refugio County (Zone 9b). 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 Refugio 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.