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When to Plant Sweet Alyssum in Trinity County, TX

Trinity County, Texas Zone 9a June

This month in Trinity County, Texas

June rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Trinity County, Texas.

Avg. last frost March 2
Avg. first frost November 23
Soil temp (4") 84°F
Watering Low
Pest pressure High
Daylight 14 hrs
  1. Collect sweet alyssum at their peak

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

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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.

Trinity County, Texas is in USDA Zone 9a. The average last spring frost is March 2 and the first fall frost is November 23, giving you a growing season of approximately 266 days.

At an elevation of 311 feet, Trinity County receives approximately 63.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 97°F, so Sweet Alyssum may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Sweet Alyssum will need more frequent watering and organic matter to retain nutrients. 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
Trinity County, TX (Zone 9a) Long season
266 days
Last Spring Frost March 2
266 growing days
First Fall Frost November 23

Trinity County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.7-6.7

Drainage

Well Drained

Sweet Alyssum Planting Risk Windows

Early Start (70% safe) ✓ Fits season (158 days to spare)
Transplant: Jan 20 🌸 Bloom: Feb 24 – Jun 9
Recommended (50%) ✓ Fits season (154 days to spare)
Transplant: Feb 2 🌸 Bloom: Mar 9 – Jun 22
Safe Start (90%) ✓ Fits season (148 days to spare)
Transplant: Feb 26 🌸 Bloom: Apr 2 – Jul 16

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 Trinity County

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

Soil pH

Your soil pH (5.7–6.7) overlaps with Sweet Alyssum's range (6.0–7.5), though not a perfect match.

Soil Texture

Sandy soil in Trinity County warms quickly in spring but drains fast. Sweet Alyssum will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Sweet Alyssum.

Organic Matter

Organic matter is low (1.9%). Add 2-3 inches of compost before planting 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 266-day season

Sow every 5.1 weeks. Last sowing by Sep 24 to harvest before frost.

For a dedicated fall crop, sow by Sep 14.

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 1.8" 0" ❄️ Dormant
Feb 2.4" 0" ❄️ Dormant
Mar 2.2" 3.4" 0" ✅ Rainfall sufficient
Apr 2.2" 5.9" 0" ✅ Rainfall sufficient
May 2.2" 10.1" 0" ✅ Rainfall sufficient
Jun 2.2" 10.8" 0" ✅ Rainfall sufficient
Jul 2.2" 6.8" 0" ✅ Rainfall sufficient
Aug 2.2" 8.4" 0" ✅ Rainfall sufficient
Sep 2.2" 5.6" 0" ✅ Rainfall sufficient
Oct 2.2" 4.4" 0" ✅ Rainfall sufficient
Nov 2.2" 2.2" 0" ✅ Rainfall sufficient
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (Mar–Nov in Trinity 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 ~1,194 GDD — county provides 6,051 GDD Excellent fit

Sweet Alyssum Planting Timeline — Trinity County, TX

Sweet Alyssum Planting Calendar

Activity When Date Range
Transplant Outdoors February 2 Feb 2 – Feb 16
Direct Sow January 5 Jan 5 – Jan 26
Bloom March 9 Mar 9 – Jun 22
Fall Sowing September 14 Sep 14 – Sep 28

· 6" apart · Rows 8" apart

Month-by-Month Timeline

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

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: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

266 days in Trinity County

Growing Tips for Sweet Alyssum in Trinity County

Direct sow Sweet Alyssum outdoors after March 02 in Trinity County when soil has warmed and frost danger has passed.

Sandy soil in Trinity County dries quickly — mulch Sweet Alyssum with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 97°F in Trinity County, provide afternoon shade for Sweet Alyssum and water deeply in the morning.

Your generous 266.0-day season in Trinity 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 Trinity County, TX?

Trinity County is in Zone 9a with an average last frost of March 2. Plan your Sweet Alyssum planting based on this frost date — see the calendar above for exact timing.

What planting zone is Trinity County, TX?

Trinity County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 2 and first fall frost is November 23.

🌱

Your Trinity County Garden Planner — Free

A 22-page printable planner built for Trinity 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 Trinity 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.