When to Plant Sweet Alyssum in Comal County, TX
Comal County, Texas gardeners: here's your June plan
We've pulled the most time-sensitive tasks for Comal County, Texas this June and put them front and centre. Tackle them in order.
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.
Comal County, Texas is in USDA Zone 9a. The average last spring frost is March 6 and the first fall frost is November 22, giving you a growing season of approximately 261 days.
At an elevation of 1,346 feet, Comal County receives approximately 58.6 inches of rainfall annually with predominantly clay soil. Summer highs average 91°F, providing good warmth for Sweet Alyssum during the growing season. Clay soil retains moisture well for Sweet Alyssum, but amend with compost to improve drainage and prevent root rot. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Sweet Alyssum root diseases.
Comal County Soil Profile
Soil Type
Clay
Soil pH
6.7-7.7
Drainage
Well Drained
Sweet Alyssum Planting Risk Windows
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 Comal County
How your county's soil matches Sweet Alyssum's growing requirements.
Soil pH
Your soil pH (6.7–7.7) overlaps with Sweet Alyssum's range (6.0–7.5), though not a perfect match.
Soil Texture
Heavy clay soil (47% clay) in Comal County compacts easily and drains slowly. Amend with compost and avoid working soil when wet.
Drainage
Sweet Alyssum prefers dry conditions but your soil drains poorly. Use raised beds or mounded rows to prevent root rot.
Organic Matter
Organic matter is moderate (3.3%). Annual compost additions will help Sweet Alyssum.
How to Plant Sweet Alyssum
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Sweet Alyssum
Sow every 5.1 weeks. Last sowing by Sep 23 to harvest before frost.
For a dedicated fall crop, sow by Sep 13.
Sweet Alyssum Water Budget
Water stress score is 6/10 — consider drought-tolerant varieties and mulching
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 | — | 1.2" | 0" | ❄️ Dormant |
| Feb | — | 2.1" | 0" | ❄️ Dormant |
| Mar | 2.2" | 3.8" | 0" | ✅ Rainfall sufficient |
| Apr | 2.2" | 6.6" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 9.4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 9.9" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 6.6" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 6.4" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 4.9" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 3.9" | 0" | ✅ Rainfall sufficient |
| Nov | 2.2" | 2" | 0.2" | 💧 Light watering |
| Dec | — | 1.6" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Mar–Nov in Comal 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 Planting Timeline — Comal County, TX
Sweet Alyssum Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Transplant Outdoors | February 6 | Feb 6 – Feb 20 |
| Direct Sow | January 9 | Jan 9 – Jan 30 |
| Bloom | March 13 | Mar 13 – Jun 26 |
| Fall Sowing | September 13 | Sep 13 – Sep 27 |
· 6" apart · Rows 8" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| 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
261 days in Comal County
Growing Tips for Sweet Alyssum in Comal County
Direct sow Sweet Alyssum outdoors after March 06 in Comal County when soil has warmed and frost danger has passed.
With Comal County's clay soil (47% clay), work in 3-4 inches of compost before planting Sweet Alyssum. Avoid tilling when soil is wet to prevent compaction.
Your generous 261.0-day season in Comal 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 →
Sweet Alyssum in Other Locations
Frequently Asked Questions
When should I plant Sweet Alyssum in Comal County, TX?
Comal County is in Zone 9a with an average last frost of March 6. Plan your Sweet Alyssum planting based on this frost date — see the calendar above for exact timing.
What planting zone is Comal County, TX?
Comal County, Texas is in USDA Hardiness Zone 9a. The average last spring frost is March 6 and first fall frost is November 22.
Your Comal County Garden Planner — Free
A 22-page printable planner built for Comal 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.