Flowers
Planting sunflowers in Maryland after the last frost — typically by mid-April — ensures your 🌻 giants get the long, warm days they crave for towering growth.
Miss that window, though, and you risk stunted blooms or frost damage, especially in Zone 7a where late cold snaps linger. I’ve seen 10-foot stalks wilt overnight when planted too early, which is why timing matters more than most gardeners realize.
This guide breaks down the exact planting dates for Maryland’s zones, plus how to prep soil, choose the right varieties, and stretch your growing season with simple tricks. Whether you’re aiming for cut flowers or birdseed, we’ve got you covered.
You’ll walk away with a clear schedule, pro tips for avoiding common mistakes, and even a few surprise varieties that thrive in Maryland’s heat and humidity. Let’s get those seeds in the ground at the perfect moment!
Maryland sunflower planting dates by hardiness Zone (with frost-free deadlines)
Maryland’s USDA Zones 6b-7b offer a 165-day frost-free window, but sunflowers need precise timing to avoid frost damage or stunted growth. In Zone 6b (northern MD), last frost typically hits around April 15, while Zone 7b (southern MD) usually warms up by March 25.
Planting too early risks cold soil, while waiting too long may shorten your 90-120 day growing season.
For direct sowing, aim for mid-April to early June—this ensures soil temperatures reach at least 55°F, ideal for germination. Transplants can go in slightly earlier (late March in Zone 7b), but they’re less common for sunflowers.
Fall planting is not recommended due to Maryland’s early October frosts cutting the season short.
Soil warmth is critical: Giant varieties like ‘Russian Giant’ need 60+ days of warmth to mature, while dwarf varieties like ‘Teddy Bear’ tolerate cooler soils. Test your soil’s readiness by pressing a 1-inch deep seed—if it’s warm to the touch, it’s time to plant.
Use row covers to extend your planting window by 2-3 weeks in Zone 6b, protecting seedlings from late frosts. Remove covers once soil warms to 60°F to prevent overheating. For fall planting, try dwarf varieties in late July—these may mature before the first frost, but expect smaller blooms.
Maryland’s humidity and summer heat (July-August) demand well-draining soil to prevent root rot. Amend clay soil with compost or sand before planting. Giant varieties need 6 inches of spacing, while dwarf types can tolerate 3 inches apart—ideal for small gardens or containers.
Monitor your local frost-free dates using the National Weather Service or Maryland Department of Agriculture tools. In Zone 7b, you can push early plantings to March 20 if using black plastic mulch to warm the soil. For Zone 6b, wait until April 22 to avoid cold soil stunting.
Sunflowers in Maryland face deer and squirrel pressure, especially in rural areas. Use deer-resistant varieties like ‘Lemon Queen’ or protect young plants with chicken wire cages. Succession planting every 2 weeks ensures continuous blooms from July to October.
Harvest time varies by variety: Dwarf types mature in 50 days, while giant varieties take 100+ days. In Maryland, expect late August to early October harvests. Cut flowers when 2/3 of petals open—this extends vase life by 3-5 days.
Pro tip: Plant ‘Autumn Beauty’ in late May for fall color—its multi-colored blooms thrive in Maryland’s cooler autumn temperatures. Pair with coreopsis or coneflowers for a long-blooming pollinator garden.
Best sunflower varieties for Maryland gardens (and their ideal planting times)
Maryland’s climate rewards sunflower lovers with long growing seasons—if you pick the right varieties. I’ve tested 10 top-performing sunflowers that thrive in Maryland’s USDA Zones 6b-7b, from dwarf varieties for containers to 12-foot giants for cut flowers.
The key? Matching each variety’s days to maturity with your planting window (mid-April to early June) to avoid frost damage.
For example, ‘Moulin Rouge’ (a stunning red-petaled variety) matures in just 50 days, making it perfect for late spring plantings, while ‘Russian Giant’ needs 120 days and should be sown by mid-May to reach its full 12-foot height.
Below, I’ve broken down the best picks for cut flowers, birdseed, and culinary use, plus their ideal planting times.
🌻 Pro Tip: Maryland’s humid summers can encourage fungal diseases in giant varieties. Space them 3 feet apart and mulch to improve airflow. For drought-prone areas (like Western Maryland), prioritize ‘Autumn Beauty’ or ‘Teddy Bear’—both tolerate moderate drought once established.