Sweet Alyssum Snow Princess
Lobularia maritima 'Snow Princess'
This award-winning sweet alyssum produces clouds of tiny white flowers with an intoxicating honey-like fragrance that attracts beneficial insects. Exceptionally heat tolerant and long-blooming, it forms a dense carpet perfect for edging, rock gardens, or spilling from containers. Unlike older varieties, Snow Princess continues blooming through summer heat without the need for cutting back.
Sun
Full sun to partial shade
Zones
5–9
USDA hardiness
Height
3-10 inches
Planting Timeline
Showing dates for Sweet Alyssum Snow Princess in USDA Zone 7
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Sweet Alyssum Snow Princess · Zones 5–9
Growing Details
Zone-by-Zone Planting Calendar
| Zone | Indoor Start | Transplant | Direct Sow | Harvest |
|---|---|---|---|---|
| Zone 3 | April – May | June – July | June – August | — |
| Zone 4 | March – April | June – June | June – July | — |
| Zone 5 | March – April | May – June | May – July | — |
| Zone 6 | March – April | May – June | May – July | — |
| Zone 7 | February – March | April – May | April – June | — |
| Zone 8 | February – March | April – May | April – June | — |
| Zone 9 | January – February | March – April | March – May | — |
| Zone 10 | January – January | February – March | February – April | — |
| Zone 1 | May – June | July – August | July – September | — |
| Zone 2 | April – May | June – July | June – August | — |
| Zone 11 | January – January | January – February | January – March | — |
| Zone 12 | January – January | January – February | January – March | — |
| Zone 13 | January – January | January – February | January – March | — |
Succession Planting
Snow Princess blooms continuously rather than producing one harvestable crop, but it's a cool-season annual that can go thin and patchy when summer heat peaks — so staggered plantings are worth doing. In zone 7, start seeds indoors in February–March and transplant out in April. Then direct sow a second round in late August or early September for fall color; soil temperatures above 85°F will drop germination rates sharply, so watch your forecast and time that second sowing to catch cooler soil.
The plant handles heat better than most Lobularia maritima varieties, but once daytime highs are consistently above 90°F it may stop flowering almost entirely. Shearing it back by about one-third at that point — rather than pulling it — often triggers a new flush of bloom when temperatures fall back into the low 70s in September.
Complete Growing Guide
Light: Full sun (6 or more hours of direct sunlight a day), Partial Shade (Direct sunlight only part of the day, 2-6 hours). Soil: Clay, Loam (Silt), Sand. Soil pH: Acid (<6.0), Alkaline (>8.0), Neutral (6.0-8.0). Drainage: Good Drainage, Moist, Occasionally Dry. Height: 0 ft. 3 in. - 0 ft. 10 in.. Spread: 0 ft. 6 in. - 1 ft. 0 in.. Spacing: 12 inches-3 feet. Growth rate: Medium. Maintenance: Medium. Propagation: Seed. Regions: Coastal, Mountains, Piedmont.
Harvesting
Cream-colored oval seed pods with 1 yellowish seed each. The fruits are numerous, rather hairy, oval to rounded.
Color: Cream/Tan, Gold/Yellow. Type: Capsule.
Storage & Preservation
Fresh Sweet Alyssum Snow Princess flowers are best used immediately after harvest for maximum flavor and fragrance. For short-term storage, place cut stems in cool water and refrigerate for up to 3 days, though fragrance diminishes quickly.
To preserve the flowers, dry them using the air-drying method: hang small bundles upside down in a dark, well-ventilated area for 7-10 days. Dried flowers retain much of their honey fragrance and work well in potpourri or herbal tea blends.
For culinary preservation, freeze individual flowers in ice cube trays with water to create decorative ice cubes for beverages. The flowers can also be pressed between parchment paper and stored in airtight containers for crafting projects. Alternatively, infuse fresh flowers in honey or simple syrup within 24 hours of harvest to capture their distinctive sweet flavor for later culinary use.
History & Origin
Origin: Southern Europe, west and central Mediterranean.
Advantages
- +Attracts: Butterflies, Moths, Pollinators, Predatory Insects, Songbirds
Companion Plants
Marigolds are the most practical companion here — they draw in hoverflies and parasitic wasps that keep aphid pressure down, and the orange-and-white color contrast is reason enough for most people to plant them together anyway. Nasturtiums pull double duty as a trap crop, drawing aphids (Myzus persicae especially) away from the Alyssum and toward stems you can cut and discard. Lobelia is worth putting next to Snow Princess because it shares the same cool-season window and nearly identical water needs — no one plant is going to out-compete the other for moisture in the top 6 inches of soil.
Black walnut trees are a hard stop: juglone leaches through the root zone and into surrounding soil, and Lobularia maritima is sensitive enough that planting within 50 feet of a walnut is likely to cost you the whole planting. Eucalyptus causes the same kind of allelopathic soil interference through leaf litter and root exudates. In our zone 7 Georgia gardens, sunflowers are tempting as a late-season backdrop, but a low-growing annual like Snow Princess will lose badly to their water draw and shade — keep at least 12 inches of separation, or just skip the combination.
Plant Together
Marigolds
Repel aphids and other pests while attracting beneficial insects
Petunias
Both attract pollinators and create attractive color combinations
Lobelia
Similar growing conditions and complementary blue flowers create beautiful contrast
Nasturtiums
Act as trap crops for aphids and add vibrant color contrast
Impatiens
Thrive in similar partial shade conditions and provide height variation
Begonias
Compatible growing requirements and complementary flowering periods
Salvia
Attracts beneficial insects and provides structural contrast to low-growing alyssum
Pansies
Cool-season compatibility and similar soil moisture preferences
Keep Apart
Black Walnut Trees
Release juglone toxin that inhibits growth of many flowering plants
Sunflowers
Allelopathic compounds can inhibit germination and growth of smaller plants
Eucalyptus
Produces allelopathic chemicals that suppress growth of nearby plants
Pests & Disease Resistance
Resistance
Good disease resistance, improved heat tolerance
Common Pests
Flea beetles, aphids, cabbage worms
Diseases
Downy mildew, white rust, damping off
Troubleshooting Sweet Alyssum Snow Princess
What you'll see, why it happens, and what to do about it.
Tiny, irregular holes punched through leaves on young transplants or seedlings
Likely Causes
- Flea beetles (Phyllotreta species) — small, jumping beetles that feed aggressively on cool-season plants
- Young transplants are most vulnerable; damage slows once plants mature and fill in
What to Do
- 1.Cover new transplants with row cover for the first 2–3 weeks after planting
- 2.Apply diatomaceous earth around the base of plants and reapply after rain
- 3.Once plants reach 6–8 inches and are actively spreading, flea beetle pressure usually becomes a non-issue
Clustered, soft-bodied insects on new growth and flower buds, sometimes with sticky residue on leaves below
Likely Causes
- Aphids (commonly green peach aphid, Myzus persicae) — they target tender new growth first
- Ant activity nearby, which farms aphid colonies and drives off predators
What to Do
- 1.Blast colonies off with a firm stream of water from the hose — do this in the morning so foliage dries before evening
- 2.Spray with insecticidal soap (follow label dilution, usually 2–3 tbsp per gallon) directly on the insects
- 3.Check for and disrupt ant trails; removing ants often lets ladybugs and parasitic wasps finish the job
Gray, fuzzy coating on the undersides of leaves, with pale yellow patches visible on the upper surface
Likely Causes
- Downy mildew (Peronospora parasitica) — a water mold that thrives in cool, humid conditions with poor airflow
- Planting too densely, closer than 6 inches, traps moisture around foliage
What to Do
- 1.Remove and bag affected leaves — don't compost them
- 2.Water at the base of the plant, not overhead, and water in the morning
- 3.Space plants to the full 6–8 inches and improve airflow; if downy mildew shows up every spring, a copper-based fungicide applied preventively on a 7–10 day schedule can slow spread
Seedlings collapse at the soil line, often with a pinched or water-soaked stem at the base
Likely Causes
- Damping off — caused by soil-borne fungi including Pythium and Rhizoctonia solani
- Overwatering or poor drainage in seed-starting trays
- Starting seeds in old, unsterilized potting mix reused from a previous season
What to Do
- 1.Use a fresh, sterile seed-starting mix — not garden soil or reused potting mix
- 2.Water from the bottom by setting trays in a shallow dish, and let the surface dry slightly between waterings
- 3.Run a small fan over the trays to improve airflow; once seedlings damp off, that batch is gone — sow fresh seed in a clean tray and start over