flower · Asteraceae
Updated Apr 2026

Zinnia

Zinnia elegans

The cutting-garden annual that will keep producing as long as you keep cutting.

Zinnia

Zinnias are one of the most productive plants you can put in a garden for the effort they ask. A dozen well-spaced plants can produce cut flowers every few days from midsummer until a hard frost kills them. The mechanism is simple: the plant's job is to set seed, and when you cut the flower before it goes to seed, the plant responds by sending up more stems. Cut early, cut often, and it will not stop.

Start seeds indoors about 4 weeks before your , or them about 1 week after it. Zinnias do not like root disturbance, so if you start them in cells, move them promptly when they're about 2 inches tall — before they become . Soil temperature matters more than air temperature: stalls below 70°F and is fastest near 80°F. Space them 12 inches apart. Crowded zinnias still bloom, but the stems stay short and the plants are more prone to powdery mildew.

The most important maintenance move with zinnias is pinching. When a or seedling has three sets of leaves, pinch out the growing tip. This pushes the plant to branch from lower nodes, and a branched plant produces dramatically more cut stems than a single-stemmed one. It feels counterintuitive to cut the plant back when it's just getting started, but the payoff shows up in August.

Powdery mildew is the main thing that can go wrong, and it will almost certainly show up by late August regardless. The white, dusty coating on leaves does not kill the plant but it weakens it and accelerates decline. Good air circulation delays the onset — that means proper spacing, not over-watering, and avoiding wetting the foliage. If you're in a humid climate, Zahara series varieties carry meaningful resistance and tend to stay cleaner late in the season. Oklahoma series also holds up well.

For cutting, harvest zinnias at what's called the 'wiggle test' stage: hold the stem near the base and give it a gentle shake. If the flower head flops, it's not ready — the stem is still soft. If the stem holds the head rigid, cut it at the length you want and put it straight into water. Stems cut at the floppy stage tend to wilt and won't recover well. A sharp knife or scissors makes a cleaner cut than tearing.

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Varieties worth knowing

Benary's Giant
The workhorse of the cut-flower zinnia world. Large blooms on strong, long stems. Available in individual colors or a wide mix.
Queen Lime
Unusual lime-green flowers that hold their color unusually well when cut. A favorite for mixed arrangements with other cool-toned flowers.
Oklahoma
Smaller blooms than Benary's Giant but on extremely long, strong stems. Good disease tolerance. Bred specifically for cutting.
State Fair
Old-fashioned, large-flowered mix. Tall plants, bold colors. A reliable choice if you want that classic zinnia look.
Zahara
Compact series bred for powdery mildew and leaf spot resistance. Stays cleaner late in the season than most varieties.
Disease resistance
PMLS
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What can go wrong

Powdery mildew
White, dusty coating on leaves, starting on the older lower leaves and moving up. Caused by humid, still air — common in late summer. Space plants well and avoid overhead watering. Zahara and Oklahoma series show meaningful resistance.
Short, weak stems on cut flowers
Usually the result of skipping the pinch at transplanting. Plants that aren't pinched tend to produce a single stem with a big first bloom, then many short side shoots. Pinch once early to build a well-branched plant.
Flowers flopping in vase
Harvest too early, before the stem has hardened. Use the wiggle test — if the stem doesn't hold the flower rigid, wait a few more days.
Seedlings damping off
Young stems pinch off at soil level and the seedlings collapse. Caused by overwatering and cool, wet soil. Ensure good drainage and don't water until the surface is dry.
Leafhoppers spreading aster yellows
Infected plants produce misshapen, greenish flowers and stunted growth. There is no cure. Pull and discard the plant. Aster yellows is sporadic but real in zinnia plantings.
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Companions

Plant with
tomatopeppercucumberbasil
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How to propagate

Zinnia is a fast-growing annual that is best direct sown after all frost danger has passed. It is one of the easiest and most rewarding flowers to grow from seed.

From seed
easy90%+ success rate
Direct sow outdoors after all danger of frost has passed and soil has warmed to at least 70F. Can start indoors 4-6 weeks before last frost, but direct sowing is preferred.
Sow seeds 1/4 inch deep, spacing 4-6 inches apart for small varieties, 8-12 inches for large types. Seeds germinate quickly in warm soil, typically in 5-7 days. Thin to final spacing once seedlings have two sets of true leaves. Zinnias dislike transplanting and cold soil, so patience in waiting for warm weather pays off. For continuous cut flowers, make successive sowings every 2-3 weeks through early summer.

Harvest & keep

Expected yield
Per plant
20–40 blooms per plant over the season
Peak window
10 weeks

Cut-and-come-again — the more you cut, the more it blooms. Pinch the first bud at 12 inches for branching.

Keep the harvest
Refrigerator
7–10 days cut (exceptional vase life for an annual)
Freeze
not applicable
Can
not applicable
Dry
dry poorly — petals shrivel, colors fade

Wiggle test: grasp the stem 8 inches below the bloom — if it bends, it's not ready; if stiff, cut.

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How it grows where you live

Pacific Northwest
Zinnias tend to thrive in the PNW's dry summers but can struggle to get started in cool, wet springs. Wait until the soil is reliably above 65°F before direct-sowing, which may be a week or two later than your last frost date. Powdery mildew can appear earlier than in drier regions — choose Oklahoma or Zahara if it's been a wet year.
Mountain West
Short growing seasons and cool nights can slow zinnia development at elevation. Start indoors 4–6 weeks before last frost and transplant after all frost risk has passed. Full sun and the dry air at altitude can reduce powdery mildew pressure, which is one advantage. Water at the base to keep foliage dry.
Southwest
Zinnias thrive in desert heat but may need more frequent watering than in other regions. Mulch around the base to retain soil moisture. In Phoenix or Tucson, plant in spring and again in late summer to avoid peak summer temperatures above 105°F, which can cause blossom drop.
Midwest
Reliable producers in the Midwest's warm summers. Direct sow after last frost when soil has warmed, or start indoors 4 weeks before. Heat and sun are rarely limiting factors. Thunderstorms can flatten tall varieties — stake them loosely or choose Oklahoma series, which has stiffer stems.
Northeast
A good climate for zinnias once summer heat arrives. Start seeds indoors 4 weeks before last frost to get a jump on the season, since outdoor soil may not warm enough for direct sowing until well into late spring. In humid summers, allow 14–18 inches between plants to help with air circulation.
Southeast
Zinnias love the heat and tend to bloom heavily through June and July. The real challenge is the humid late summer, which accelerates powdery mildew. Zahara series holds up better than most under southern conditions. In Florida and along the Gulf Coast, a second planting in late summer can extend the season into fall.
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Sources

Native range: Mexico
A general reference — results depend on your soil, weather, and season.