You've picked up a promising plant at the nursery and the tag is covered in symbols, zones, and small print. What does it all mean? Nursery plant tags follow a fairly consistent system once you know the code. Here's a complete walkthrough.
Sun Symbols: Full Sun, Part Sun, Part Shade, Full Shade
The sun icon is usually the first symbol on a tag. A fully filled circle or bright yellow sun means Full Sun — 6 or more hours of direct sunlight per day. A half-filled circle indicates Part Sun or Part Shade — typically 3–6 hours. Some tags split this further: Part Sun means the plant prefers more sun in that range, Part Shade prefers less. A crescent or very dim circle means Full Shade — under 3 hours of direct light. For most vegetables and fruiting plants, you want full sun. Visit our beginner gardening guides to learn which crops can get by with less.
Watering Icons
Watering symbols vary more by brand than sun icons, but most use a raindrop or water drop with modifiers. A single drop usually means low water needs (drought-tolerant once established). Two drops indicate average moisture — water when the top inch of soil is dry. Three drops or a drop with waves means consistently moist soil. Some tags use descriptive words instead: "drought tolerant," "moderate water," "keep moist." When in doubt, a tag that says "average water" is telling you not to let the plant dry out or sit in water — both are stressful.
USDA Hardiness Zones
The zone number tells you where this plant can survive winter. Zone maps divide North America into bands based on average annual minimum temperature. A perennial labeled "Zones 5–9" survives winters down to -20°F (Zone 5) and up to winter lows around 25°F (Zone 9). If you're in Zone 6, any perennial rated 6 or lower is reliably hardy for you. Annuals and vegetables don't have zone ratings — they live one season regardless. Check our growing by zone guide to find your zone and what it means for your garden.
Mature Size: Height x Width
Tags list mature size as height x width, often in inches or feet. "18–24 inches tall, 12–18 inches wide" tells you the territory this plant will eventually claim. Beginners frequently underestimate mature size and plant things too close together. A shrub that looks small at the nursery in a 1-gallon pot may be 4 feet wide in three years. Follow the spacing guidance on the tag. For containers, choose plants whose mature size fits the pot with room to spare.
Bloom Time and Color
Tags on flowering plants typically list bloom time by season (Spring, Summer, Fall) and flower color. Perennial tags may also note whether a plant is a re-bloomer — meaning it flowers more than once per season. For planning a continuous-color garden, stagger plants with different bloom times. For edible gardens, flowering herbs like basil attract pollinators when allowed to bloom, though the leaves become more bitter.
Annual, Perennial, and Biennial
Annual means the plant completes its full life cycle in one growing season — you replant each year. Perennial means it returns from the roots year after year. Biennial grows foliage the first year and flowers/seeds the second before dying. Most vegetables are annuals. Asparagus, rhubarb, and many herbs are perennials. Understanding which you're buying affects both your budget and how you plan bed space long-term.
Frequently Asked Questions
- What does "heat tolerant" mean on a plant tag?
- It means the plant performs well above 90°F without wilting, bolting, or dropping flowers. This is different from drought tolerance — a heat-tolerant plant may still need regular water, it just handles hot air temperatures well.
- What if I can't find my zone on the tag?
- Look up your USDA hardiness zone at the USDA Plant Hardiness Zone Map website using your zip code. Most of the continental US falls between zones 4 and 10. Once you know your zone, you can evaluate any plant tag instantly.
- Do deer-resistant plants really work?
- Deer-resistant means deer generally avoid the plant, not that they'll never eat it. Hungry deer will eat almost anything. Plants labeled deer-resistant are a smart choice in deer-pressure areas, but no plant is guaranteed safe in a hard winter when food is scarce.
- What does "self-seeding" mean on a tag?
- A self-seeding plant drops seeds that germinate on their own the following season. This can be a benefit (free plants) or a nuisance (plants appearing where you didn't plan). Know before you plant whether you want the plant spreading on its own.
- Is a plant rated "Zone 7" safe in Zone 6?
- Not reliably. Zone 7 minimum temperatures are around 0–10°F. Zone 6 dips to -10–0°F. A Zone 7 plant in Zone 6 may survive mild winters but will likely die in a cold snap. Treat it as a tender perennial you may need to replace, or overwinter it in a protected location.