When to Plant Zinnias in Maryland
The cut-and-come-again champion. The more you cut zinnias, the more they bloom. A cottage garden essential.
The Short Answer
Maryland Frost Dates
Your planting dates depend on which part of Maryland you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Western Maryland | 5b, 6a | May 1 - May 15 | Sep 25 - Oct 10 |
| Central Maryland | 6b, 7a | Apr 10 - Apr 25 | Oct 10 - Oct 25 |
| Eastern Shore | 7a, 7b, 8a | Apr 1 - Apr 15 | Oct 20 - Nov 5 |
Zinnias Planting Schedule for Maryland
Western Maryland (Zones 5b, 6a)
Average last frost: May 1 - May 15 · Average first frost: Sep 25 - Oct 10
Central Maryland (Zones 6b, 7a)
Average last frost: Apr 10 - Apr 25 · Average first frost: Oct 10 - Oct 25
Eastern Shore (Zones 7a, 7b, 8a)
Average last frost: Apr 1 - Apr 15 · Average first frost: Oct 20 - Nov 5
Growing Zinnias in Maryland
Zinnias in Maryland's Climate
Your warm, humid summers grow zinnias prolifically. Direct sow from mid-May. Powdery mildew is the main issue in humid conditions — water at the base, never overhead, and choose mildew-resistant varieties. Cut or deadhead regularly for continuous bloom through frost.
Soil Considerations for Maryland
Clay soils in Piedmont. Sandy loam on Eastern Shore. Acidic in most areas. Rich alluvial soils along river valleys. Make sure soil has warmed to at least 60°F before planting zinnias outside.
Maryland Climate & Growing Season
Moderate climate with four seasons. Hot, humid summers. Good growing season. Diverse growing conditions across the state. Zinnias cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.
Growing season length varies across Maryland: Western Maryland (5b, 6a) has a last frost around May 1 - May 15, while Eastern Shore (7a, 7b, 8a) sees frost end around Apr 1 - Apr 15. This difference matters for zinnias — transplant timing shifts by several weeks across the state.
Growing Tips
Water at the base to prevent powdery mildew. Cut flowers just above a leaf node to encourage more branching and blooms.
Companion Planting
Plant zinnias alongside these companions for better growth:
The Bottom Line
Last reviewed: March 29, 2026